Project: Apollo (Provisioning / Automation & Configuration)
File: java-sdk-user-guide.md

Note: This document is intended for users of Apollo systems. If you are a developer/maintainer of Apollo systems in your company, it is recommended to refer to first. Java: 1.8+ To run in Java 1.7 runtime environment, please use 1.x version of apollo client, such as 1.9.1 Guava: 20.0+ The Apollo client will reference Guava 29 by default. If your project references other versions, make sure the version number is greater than or equal to 20.0 Note: For Apollo client, you can make a few code changes to downgrade to Java 1.6 if needed, see for details Apollo client depends on `AppId`, `Apollo Meta Server` and other environment information to work, so please make sure to read the following instructions and do the correct configuration. AppId is the identity of the application and is an important piece of information to get the configuration from the server. There are several ways to set it, from highest to lowest priority, as follows. System Property Apollo 0.7.0+ supports passing in app.id information via System Property, such as ```bash -Dapp.id=YOUR-APP-ID ``` System Environment of the operating system Apollo 1.4.0+ supports passing app.id information via the operating system's System Environment `APP_ID`, as in ```bash APP_ID=YOUR-APP-ID ``` Spring Boot application.properties Apollo 1.0.0+ supports configuration via Spring Boot's application.properties file, such as ```properties app.id=YOUR-APP-ID ``` This configuration does not work with multiple war packages deployed in the same tomcat app.properties Make sure that the classpath:/META-INF/app.properties file exists and that its contents look like. app.id=YOUR-APP-ID The file location reference is as follows. Note: app.id is a unique id used to identify the application identity in the format string. Apollo supports applications with different configurations in different environments, so you need to provide the information of the current environment to Apollo clients at runtime. By default, the meta server and config service are deployed in the same JVM process, so the address of the meta server is the address of the config service. To achieve high availability of meta server, it is recommended to do dynamic load balancing by SLB (Software Load Balancer). meta server address can also be filled with IP, such as `http://1.1.1.1:8080,http://2.2.2.2:8080`, but it is still recommended for production environment Use the domain name (go SLB), because machine expansion, shrinkage, etc. may lead to changes in the IP list. The following ways to configure apollo meta server information are supported since version 1.0.0, in descending order of priority Via the Java System Property `apollo.meta` Can be specified via the Java System Property `apollo.meta` Can be specified in the Java program startup script with `-Dapollo.meta=http://config-service-url` If you are running a jar file, you need to note that the format is `java -Dapollo.meta=http://config-service-url -jar xxx.jar` You can also specify it programmatically, e.g. `System.setProperty("apollo.meta", "http://config-service-url");` Through the Spring Boot configuration file You can specify `apollo.meta=http://config-service-url` in `application.properties` or `bootstrap.properties` of Spring Boot This configuration does not work with multiple war packages deployed in the same tomcat Through the operating system's System Environment `APOLLO_META` Can be specified by System Environment `APOLLO_META` of the operating system Note that the key is all-caps and separated by `_`. Via `server.properties` configuration file You can specify `apollo.meta=http://config-service-url` in the `server.properties` configuration file For Mac/Linux, the default file location is `/sopt/settings/server.properties`. For Windows, the default file location is `C:\opt\settings\server.properties` Via the `app.properties` configuration file You can specify `apollo.meta=http://config-service-url` in

Via Java system property `${env}_meta` If the current is `dev`, then the user can configure `-Ddev_meta=http://config-service-url` Using this configuration method, then the Environment must be configured correctly, see for details Via the OS System Environment `${ENV}_META` (supported since version 1.2.0) If the current is `dev`, then the user can configure the OS System Environment `DEV_META=http://config-service-url` Note that the key is all-caps Using this configuration method, then the Environment must be configured correctly, see for details Via the `apollo-env.properties` file The user can also create an `apollo-env.properties` and put it under the classpath of the application or under the config directory of the spring boot application If you use this configuration, then you must configure the Environment correctly, see The contents of the file look like this. ```properties dev.meta=http://1.1.1.1:8080 fat.meta=http://apollo.fat.xxx.com uat.meta=http://apollo.uat.xxx.com pro.meta=http://apollo.xxx.com ``` If the Meta Server address cannot be obtained by any of the above means, Apollo will eventually fallback to `http://apollo.meta` as the Meta Server address In version 1.0.0, Apollo provides the , which allows users to inject their own MetaServerProvider to customize the Meta Server address location logic. Since we use the typical , it is still relatively simple to implement. One thing to note is that apollo will iterate through all MetaServerProviders in order at runtime until a MetaServerProvider provides a non-empty Meta Server address, so users need to pay extra attention to the Order of the custom MetaServerProvider. The rule is that smaller Order has higher priority, so MetaServerProvider with Order=0 will be ranked ahead of MetaServerProvider with Order=1. If your company has many applications that need to access Apollo, it is recommended to package a jar package and then provide a custom Apollo Meta Server positioning logic so that the applications that access Apollo can be used with zero configuration. For example, write your own `xx-company-apollo-client`, the jar package depends on `apollo-client`, define a custom MetaServerProvider implementation in the jar package by spi, and then the application directly depends on `xx-company-apollo-client`. The implementation of MetaServerProvider can be found in and . For apollo-client version 0.11.0 and above In general, it is recommended to use Apollo's Meta Server mechanism to implement service discovery for Config Service, so that high availability of Config Service can be achieved. However, apollo-client also supports skipping Meta Server service discovery, which is mainly used in the following scenarios: 1. Config Service is deployed on the public cloud, and the address registered to Meta Server is an intranet address, so the local development environment cannot connect directly If the Config Service is exposed through the public SLB, remember to set the IP whitelist to avoid data leakage. Config Service is deployed in docker environment, and the address registered to Meta Server is docker intranet address, so local development environment cannot connect to it directly. Config Service is deployed in kubernetes, and you want to use kubernetes' own service discovery capability (Service). For the above scenarios, you can skip Meta Server service discovery by directly specifying the Config Service address, in descending order of priority, as follows Via Java System Property `apollo.config-service` (1.9.0+) or `apollo.configService` (before 1.9.0) Can be specified via Java's System Property `apollo.config-service` (1.9.0+) or `apollo.configService` (before 1.9.0) In the Java program startup script, you can specify `-Dapollo.config-service=http://config-service-url:port` If you are running a jar file, you need to note that the format is `java -Dapollo.configService=http://config-service-url:port -jar xxx.jar` It can also be specified programmatically, such as `System.setProperty("apollo.config-service", "http://config-service-url:port");` Through the operating system's System Environment `APOLLOCONFIGSERVICE` (1.9.0+) or `APOLLO_CONFIGSERVICE` (before 1.9.0) Can be specified by System Environment `APOLLOCONFIGSERVICE`(1.9.0+) or `APOLLO_CONFIGSERVICE`(before

of the operating system Note that the key is all-caps and separated by `_`. Via `server.properties` configuration file You can specify `apollo.config-service=http://config-service-url:port`(1.9.0+) or `apollo.configService=http://config-service-url:port` in the `server.properties` configuration file (before 1.9.0) For Mac/Linux, the default file location is `/opt/settings/server.properties` For Windows, the default file location is `C:\opt\settings\server.properties` The Apollo client will cache a copy of the configuration obtained from the server in the local file system, so that if the service is unavailable or the network is down, the configuration can still be restored locally without affecting the normal operation of the application. The local cache path is located in the following path by default, so please make sure `/opt/data` or `C:\opt\data\` directory exists and the application has read/write permission. Mac/Linux*: /opt/data/{appId}/config-cache Windows*: C:\opt\data\\\{appId}\config-cache The local configuration file will be placed under the local cache path in the following filename format. _{appId}+{cluster}+{namespace}.properties_ AppId is the application's own appId, e.g. 100004458 Cluster is the cluster used by the application, generally in local mode without configuration, it is default Namespace is the configuration `namespace` used by the application, usually `application` The content of the file is stored in properties format, for example, if there are two keys, one is request.timeout, and the other is batch, then the content of the file is in the following format. ```properties request.timeout=2000 batch=2000 ``` The following custom cache paths are supported since version 1.0.0, in descending order of priority Via the Java System Property `apollo.cache-dir` (1.9.0+) or `apollo.cacheDir` (before 1.9.0) Can be specified by Java's System Property `apollo.cache-dir`(1.9.0+) or `apollo.cacheDir`(before 1.9.0) In the Java program startup script, you can specify `-Dapollo.cache-dir=/opt/data/some-cache-dir`(1.9.0+) or `apollo.cacheDir=/opt/data/some-cache-dir`(before 1.9.0) If you are running a jar file, note that the format is `java -Dapollo.cache-dir=/opt/data/some-cache-dir -jar xxx.jar` (1.9.0+) or `java -Dapollo.cacheDir=/opt/data/some-cache-dir -jar xxx.jar`(before 1.9.0) Can also be specified programmatically, e.g. `System.setProperty("apollo.cache-dir", "/opt/data/some-cache-dir");`(1.9.0+) or `System.setProperty("apollo.cacheDir", "/opt/data/some-cache-dir");`(before 1.9.0) Via the Spring Boot configuration file You can specify `apollo.cache-dir=/opt/data/some-cache-dir` (1.9.0+) or `apollo. cacheDir=/opt/data/some-cache-dir`(before 1.9.0) Via OS System Environment `APOLLOCACHEDIR` (1.9.0+) or `APOLLO_CACHEDIR` (before 1.9.0) Can be specified by the OS System Environment `APOLLOCACHEDIR`(1.9.0+) or `APOLLO_CACHEDIR`(before 1.9.0) Note that the key is all-caps and separated by `_`. Via `server.properties` configuration file You can specify `apollo.cache-dir=/opt/data/some-cache-dir`(1.9.0+) or `apollo.cacheDir=/opt/data/some-cache-dir`(before 1.9. 0) in the `server.properties` configuration file. 0 or earlier) For Mac/Linux, the default file location is `/opt/settings/server.properties` For Windows, the default file location is `C:\opt\settings\server.properties` Note: The local cache path can also be used for the disaster recovery directory. If the application needs to be expanded when all the config services are down, then the configuration can also be copied from the cache path on the existing machine to the same cache path on the new machine first The Environment can be configured in any of the following 3 ways. Via Java System Property Environment can be specified through Java's System Property `env`. In the Java program startup script, you can specify `-Denv=YOUR-ENVIRONMENT` If you are running a jar file, note that the format is `java -Denv=YOUR-ENVIRONMENT -jar xxx.jar` Note that the key is all lowercase Through the operating system's System Environment You can also specify the System Environment `ENV` of the operating system Note that the key is all uppercase Through the configuration file The last recommended way is to specify `env=YOUR-ENVIRONMENT` through the configuration file For Mac/Linux, the default file location is `/opt/settings/server.properties`. For Windows, the default file location is `C:\opt\settings\server.properties`. The contents of the file look like : ```properties env=DEV ``` Currently, `env` supports the following values

DEV Development environment FAT Feature Acceptance Test environment UAT User Acceptance Test environment PRO Production environment For more environment definitions, you can refer to Apollo supports configuration by cluster, which means that for an appId and an environment, there can be different configurations for different clusters. The following ways of clustering are supported since version 1.0.0, in descending order of priority. Via Java System Property `apollo.cluster` can be specified via Java's System Property `apollo.cluster` Can be specified in the Java program startup script with `-Dapollo.cluster=SomeCluster` If you are running a jar file, you need to note that the format is `java -Dapollo.cluster=SomeCluster -jar xxx.jar` You can also specify it programmatically, e.g. `System.setProperty("apollo.cluster", "SomeCluster");` Through the Spring Boot configuration file You can specify `apollo.cluster=SomeCluster` in `application.properties` or `bootstrap.properties` of Spring Boot Via Java System Property You can specify the environment via Java's System Property `idc`. In the Java program startup script, you can specify `-Didc=xxx` If you are running a jar file, you should note that the format is `java -Didc=xxx -jar xxx.jar` Note that the key is all lowercase Through the operating system's System Environment Can also be specified by the operating system's System Environment `IDC Note that the key is all uppercase Through the `server.properties` configuration file You can specify `idc=xxx` in the `server.properties` configuration file For Mac/Linux, the default file location is `/opt/settings/server.properties`. For Windows, the default file location is `C:\opt\settings\server.properties` Cluster Precedence (cluster order) If `apollo.cluster` and `idc` are both specified. It will first try to load the configuration from the cluster specified by `apollo.cluster` If nothing is found, we try to load the configuration from the cluster specified by `idc`. If nothing is found, we will load from the default cluster (`default`) If only `apollo.cluster` is specified. We will first try to load the configuration from the cluster specified by `apollo.cluster` If not found, it will be loaded from the default cluster (`default`) If only `idc` is specified. We will first try to load the configuration from the cluster specified by `idc` If not found, it will be loaded from the default cluster (`default`) If neither `apollo.cluster` nor `idc` is specified. It will load the configuration from the default cluster (`default`) For versions 1.6.0 and above By default, the in-memory configuration of the apollo client is stored in Properties (Hashtable underneath) and is not intentionally kept in the same order as seen on the page, which has no effect on most scenarios. However, some scenarios will strongly rely on the order of configuration items (such as the routing rules of spring cloud zuul), for this case, you can turn on the OrderedProperties feature to make the in-memory configuration order consistent with what you see on the page. The configuration methods, in descending order of priority, are Via the Java System Property `apollo.properties.order.enable Can be specified via Java's System Property `apollo.property.order.enable` You can specify `-Dapollo.property.order.enable=true` in the Java program startup script If you are running a jar file, you need to note that the format is `java -Dapollo.property.order.enable=true -jar xxx.jar` You can also specify it programmatically, such as `System.setProperty("apollo.property.order.enable", "true");` Via the Spring Boot configuration file You can specify `apollo.properties.order.enable=true` in Spring Boot's `application.properties` or `bootstrap.properties` Via the `app.properties` configuration file You can specify `apollo.properties.order.enable=true` in `classpath:/META-INF/app.properties` For versions 1.6.0 and above Apollo has added an access key mechanism since version 1.6.0 so that only authenticated clients can access sensitive configurations. If the application has access keys enabled, the client needs to configure the keys, otherwise the configuration cannot be

The configuration methods are as follows, in descending order of priority Via Java System Property `apollo.access-key.secret` (1.9.0+) or `apollo.accessskey.secret` (before 1.9.0) Can be specified via Java's System Property `apollo.access-key.secret` (1.9.0+) or `apollo.accessskey.secret` (before 1.9.0) In the Java application startup script, you can specify `-Dapollo.access-key.secret=1cf998c4e2ad4704b45a98a509d15719` (1.9.0+) or `-Dapollo.accesskey.secret=1cf998c4e2ad4704b45a98a509d15719`(before 1.9.0) If running a jar file, note that the format is `java -Dapollo.access-key.secret=1cf998c4e2ad4704b45a98a509d15719 -jar xxx.jar` (1.9.0+) or `java -Dapollo.accesskey.secret=1cf998c4e2ad4704b45a98a509d15719 -jar xxx.jar`(before 1.9.0) Can also be specified programmatically, such as `System.setProperty("apollo.access-key.secret", "1cf998c4e2ad4704b45a98a509d15719");`(1.9.0+) or `System.setProperty("apollo.accesskey.secret", "1cf998c4e2ad4704b45a98a509d15719");` (before 1.9.0) Via the Spring Boot configuration file You can specify `apollo.access-key.secret=1cf998c4e2ad4704b45a98a509d15719` in `application.properties` or `bootstrap.properties` of Spring Boot (1.9.0 +) or `apollo.accesskey.secret=1cf998c4e2ad4704b45a98a509d15719` (before 1.9.0) Through the operating system's System Environment Can also be specified through the OS System Environment `APOLLOACCESSKEYSECRET`(1.9.0+) or `APOLLOACCESSKEY_SECRET`(before 1.9.0) Note that the key is all-caps Via `app.properties` configuration file You can specify `apollo.access-key.secret=1cf998c4e2ad4704b45a98a509d15719`(1.9.0+) or `apollo.accessskey.secret=1cf998c4e2ad4704b45a98a509d15719`(before 1.9.0) for version 1.8.0 and above The following ways to customize the server.properties path are supported since version 1.8.0, in descending order of priority Via the Java System Property `apollo.path.server.properties` Can be specified via the Java System Property `apollo.path.server.properties` You can specify `-Dapollo.path.server.properties=/some-dir/some-file.properties` in the Java program startup script If you are running a jar file, you need to note that the format is `java -Dapollo.path.server.properties=/some-dir/some-file.properties -jar xxx.jar` Can also be specified programmatically, e.g. `System.setProperty("apollo.path.server.properties", "/some-dir/some-file.properties");` Via the operating system's System Environment `APOLLOPATHSERVER_PROPERTIES` can be specified by System Environment `APOLLOPATHSERVER_PROPERTIES` of the operating system Note that the key is all-caps and separated by `_`. For version 1.9.0 and above In scenarios where `@ConfigurationProperties` is used and there are a large number of configuration items, the Spring container can be slow to start. This configuration can be turned on to significantly improve startup speed, and the cache will be automatically cleared when the configuration changes, default is `false`. See: The configuration methods, in descending order of priority, are via Java System Property `apollo.property.names.cache.enable` can be specified via the Java System Property `apollo.property.names.cache.enable` You can specify `-Dapollo.property.names.cache.enable=true` in the Java program startup script If you are running a jar file, note that the format is `java -Dapollo.property.names.cache.enable=true -jar xxx.jar` You can also specify it programmatically, such as `System.setProperty("apollo.property.names.cache.enable", "true");` via system environment variables Configure the environment variable `APOLLOPROPERTYNAMESCACHEENABLE=true` before starting the program to specify Note that the key is all-caps and separated by `_`. via the Spring Boot configuration file You can specify `apollo.properties.names.cache.enable=true` in Spring Boot's `application.properties` or `bootstrap.properties`. via the `app.properties` configuration file You can specify `apollo.property.names.cache.enable=true` in `classpath:/META-INF/app.properties` ApolloLabel is the label information of the application, an important piece of information to get the configuration from the server side for the grayscale rules. There are several ways to set it, from highest to lowest priority, as follows. System Property Apollo 2.0.0+ supports passing in apollo.label information via System Property, such as ```bash -Dapollo.label=YOUR-APOLLO-LABEL ``` System Environment of the operating system Apollo 2.0.0+ supports passing apollo.label information through the operating system's System Environment ``APP_LABEL``, as in ```bash APOLLO_LABEL=YOUR-APOLLO-LABEL ``` Spring boot `application.properties` Apollo 2.0.0+ supports configuration via Spring Boot's application.properties file, such as ```properties apollo.label=YOUR-APOLLO-LABEL ``` This configuration is not suitable for multiple war packages deployed in the same tomcat scenario `app.properties` Make sure that the `classpath:/META-INF/app.properties` file exists and that its contents are shaped like. apollo.label=YOUR-APOLLO-LABEL The file location reference is as follows. Note: apollo.label is a label used to identify the application identity in the format string. For version 2.1.0 and above Flag to indicate that Apollo's remote properties should override system properties. Default

The configuration methods, in descending order of priority, are Via the Java System Property `apollo.override-system-properties` Can be specified via Java's System Property `apollo.override-system-properties` You can specify `-Dapollo.override-system-properties=true` in the Java program startup script If you are running a jar file, you need to note that the format is `java -Dapollo.override-system-properties=true -jar xxx.jar` You can also specify it programmatically, such as `System.setProperty("apollo.override-system-properties", "true");` Via the Spring Boot configuration file You can specify `apollo.override-system-properties=true` in Spring Boot's `application.properties` or `bootstrap.properties` Via the `app.properties` configuration file You can specify `apollo.override-system-properties=true` in `classpath:/META-INF/app.properties` Apollo's client jar package has been uploaded to the central repository, the application only needs to be introduced in the following way when it is actually used. ```xml <dependency> <groupId>com.ctrip.framework.apollo</groupId> <artifactId>apollo-client</artifactId> <version>1.7.0</version> </dependency> ``` Apollo supports API approach and Spring integration approach, how to choose which one to use? The API approach is flexible, fully functional, configuration values are updated in real time (hot release), and supports all Java environments. Spring approach is easy to access and has N cool ways to play with Spring, such as Placeholder way. Direct use in the code, such as: `@Value("${someKeyFromApollo:someDefaultValue}")` Replace the placeholder in the configuration file, e.g.: `spring.datasource.url: ${someKeyFromApollo:someDefaultValue}` Directly hosting spring's configuration, such as directly configuring `spring.datasource.url=jdbc:mysql://localhost:3306/somedb?characterEncoding=utf8` in apollo Spring boot's method Versions from v0.10.0 onwards support automatic update of placeholder at runtime, see for details. (Versions prior to v0.10.0 do not re-inject after configuration changes and require a restart to update. If you need real-time updates of configuration values, you can refer to the subsequent description in The Spring approach can also be used in combination with the API approach, such as injecting Apollo's Config object, you can get the configuration as usual through the API approach: ```java @ApolloConfig private Config config; //inject config for namespace application ``` For more interesting practical usage scenarios and sample code, please refer to The API approach is the easiest and most efficient way to use Apollo configuration without relying on the Spring Framework to use it. ```java Config config = ConfigService.getAppConfig(); //config instance is singleton for each namespace and is never null String someKey = "someKeyFromDefaultNamespace"; String someDefaultValue = "someDefaultValueForTheKey"; String value = config.getProperty(someKey, someDefaultValue); ``` With the above config.getProperty you can get the real-time latest configuration value corresponding to someKey. In addition, the configuration values are fetched from memory, so there is no need for the application to do its own caching. Listening for configuration change events is only used when the application really cares about configuration changes and needs to be notified when the configuration changes, e.g. when the database connection string changes and the connection needs to be rebuilt, etc. If you just want to fetch the latest configuration every time, just follow the example above and call config.getProperty. ```java Config config = ConfigService.getAppConfig(); //config instance is singleton for each namespace and is never null config.addChangeListener(new ConfigChangeListener() { @Override public void onChange(ConfigChangeEvent changeEvent) { System.out.println("Changes for namespace " + changeEvent.getNamespace()); for (String key : changeEvent.changedKeys()) { ConfigChange change = changeEvent.getChange(key); System.out.println(String.format("Found change - key: %s, oldValue: %s, newValue: %s, changeType: %s", change.getPropertyName(), change. getOldValue(), change.getNewValue(), change.getChangeType())); } } }); ``` ``` java String somePublicNamespace = "CAT"; Config config = ConfigService.getConfig(somePublicNamespace); //config instance is singleton for each namespace and is never null String someKey = "someKeyFromPublicNamespace"; String someDefaultValue = "someDefaultValueForTheKey"; String value = config.getProperty(someKey, someDefaultValue); ``` Apollo-Client version 1.3.0 starts to make better support for `yaml/yml`, which is used in the same way as properties format. ```java Config config =

String someKey = "someKeyFromYmlNamespace"; String someDefaultValue = "someDefaultValueForTheKey"; String value = config.getProperty(someKey, someDefaultValue); ``` To get it, you need to use the `ConfigService.getConfigFile` interface and specify the Format, such as `ConfigFileFormat.XML`. ```java String someNamespace = "test"; ConfigFile configFile = ConfigService.getConfigFile("test", ConfigFileFormat.XML); String content = configFile.getContent(); ``` Apollo also supports integration with Spring (Spring 3.1.1+), and only requires some simple configuration. Apollo currently supports both the more traditional `XML-based` configuration and the currently more popular `Java-based (recommended)` configuration. In case of Spring Boot environments, it is recommended to refer to for configuration. Note that if you have previously used `org.springframework.beans.factory.config.PropertyPlaceholderConfigurer`, please replace it with `org.springframework.context.support.PropertySourcesPlaceholderConfigurer`. It is not recommended to use PropertyPlaceholderConfigurer after Spring 3.1, use PropertySourcesPlaceholderConfigurer instead. If you have used `<context:property-placeholder>` before, please note that the `spring-context.xsd` version introduced in the xml needs to be 3.1 or higher (usually it will be upgraded automatically as long as no version is specified), and it is recommended to introduce it without the version number, e.g.: `http://www.springframework.org/schema/context/spring-context.xsd` Note 1: namespace in yaml/yml format supports integration with Spring since version 1.3.0, when injecting you need to fill in the full name with a suffix, such as application.yml Note 2: Non-properties, non-yaml/yml formatted namespace (e.g. xml, json, etc.) do not support integration with Spring at this time. Note: You need to add apollo related xml namespace to the configuration file header, otherwise it will report xml syntax errors. Inject the default namespace configuration into Spring ```xml <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:apollo="http://www.ctrip.com/schema/apollo" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.ctrip.com/schema/apollo http://www.ctrip.com/schema/apollo.xsd"> <! -- This is the simplest form of configuration, which is generally sufficient for applications, and is used to instruct Apollo to inject the configuration of the application namespace into the Spring environment --> <apollo:config/> <bean class="com.ctrip.framework.apollo.spring.TestXmlBean"> <property name="timeout" value="${timeout:100}"/> <property name="batch" value="${batch:200}"/> </bean> </beans> ``` Inject multiple namespace configuration into Spring ```xml <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:apollo="http://www.ctrip.com/schema/apollo" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.ctrip.com/schema/apollo http://www.ctrip.com/schema/apollo.xsd"> <! -- This is the simplest form of configuration, which is generally sufficient for applications, and is used to instruct Apollo to inject the configuration of the application namespace into the Spring environment --> <apollo:config/> <! -- This is a slightly more complex form of configuration that instructs Apollo to inject the configuration of FX.apollo and application.yml namespace into the Spring environment --> <apollo:config namespaces="FX.apollo,application.yml"/> <bean class="com.ctrip.framework.apollo.spring.TestXmlBean"> <property name="timeout" value="${timeout:100}"/> <property name="batch" value="${batch:200}"/> </bean> </beans> ``` Inject multiple namespaces and specify the order If multiple property sources have the same key, then the configuration with the highest order will take effect. If <apollo:config> does not specify an order, then the default is the lowest priority. ```xml <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:apollo="http://www.ctrip.com/schema/apollo" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.ctrip.com/schema/apollo http://www.ctrip.com/schema/apollo.xsd"> <apollo:config order="2"/> <! -- This is the most complex form of configuration, instructing Apollo to inject the configuration of FX.apollo and application.yml namespace into the Spring environment, and in order before application --> <apollo:config namespaces="FX.apollo,application.yml" order="1"/> <bean class="com.ctrip.framework.apollo.spring.TestXmlBean"> <property name="timeout" value="${timeout:100}"/> <property name="batch" value="${batch:200}"/> </bean> </beans> ``` Java-based configuration is currently the more popular approach as opposed to XML-based configuration. Note that `@EnableApolloConfig` should be used together with `@Configuration`, otherwise it will not take

Inject the default namespace configuration into Spring ```java // This is the simplest form of configuration and is generally used by applications to instruct Apollo to inject the configuration of application namespace into the Spring environment @Configuration @EnableApolloConfig public class AppConfig { @Bean public TestJavaConfigBean javaConfigBean() { return new TestJavaConfigBean(); } } ``` Inject multiple namespace configuration into Spring ```java @Configuration @EnableApolloConfig public class SomeAppConfig { @Bean public TestJavaConfigBean javaConfigBean() { return new TestJavaConfigBean(); } } // This is a slightly more complex form of configuration, instructing Apollo to inject the configuration of FX.apollo and application.yml namespace into the Spring environment @Configuration @EnableApolloConfig({"FX.apollo", "application.yml"}) public class AnotherAppConfig {} ``` Inject multiple namespaces and specify the order ```java // This is the most complex form of configuration, instructing Apollo to inject the configuration of FX.apollo and application.yml namespace into the Spring environment, and in the order before application @Configuration @EnableApolloConfig(order = 2) public class SomeAppConfig { @Bean public TestJavaConfigBean javaConfigBean() { return new TestJavaConfigBean(); } } @Configuration @EnableApolloConfig(value = {"FX.apollo", "application.yml"}, order = 1) public class AnotherAppConfig {} ``` Spring Boot supports the above two integration methods in addition to configuration via application.properties/bootstrap.properties, which enables configuration to be injected at an earlier stage, such as scenarios that use `@ConditionalOnProperty` or have some spring-boot-starter needs to read the configuration to do something in the startup phase (e.g. ). So for Spring Boot environment it is recommended to access Apollo (requires version 0.10.0 and above) by the following way. It is very simple to use, you just need to configure it in application.properties/bootstrap.properties according to the following sample. Example configuration with default ``application`` namespace injected ```properties apollo.bootstrap.enabled = true ``` Example configuration for injecting non-default ``application`` namespace or multiple namespaces ```properties apollo.bootstrap.enabled = true apollo.bootstrap.namespaces = application,FX.apollo,application.yml ``` Load Apollo configuration before initializing the logging system (1.2.0+) Starting with version 1.2.0, if you wish to put logging-related configuration (such as `logging.level.root=info` or parameters in `logback-spring.xml`) in Apollo management as well, then you can additionally configure `apollo.bootstrap.eagerLoad. enabled=true` to put Apollo loading order before logging system loading, for more information you can refer to . The reference configuration example is as follows. ```properties apollo.bootstrap.enabled = true apollo.bootstrap.eagerLoad.enabled = true ``` For Spring Boot 2.4+ versions there is also support for loading configurations via Config Data Loader mode `apollo-client-config-data` already depends on `apollo-client`, so you only need to add this one dependency, not the apollo-client dependency ```xml <dependencies> <dependency> <groupId>com.ctrip.framework.apollo</groupId> <artifactId>apollo-client-config-data</artifactId> <version>1.9.0</version> </dependency </dependencies> ``` Use the default namespace `application` ```properties spring.config.import=apollo:// ``` or ```properties spring.config.import=apollo://application ``` Use custom namespace ```properties spring.config.import=apollo://your-namespace ``` Using multiple namespaces Note: `spring.config.import` loads the configuration from back to front, while `apollo.bootstrap.namespaces` loads it from back to front, just the opposite. To ensure consistency with the original logic, reverse the order of namespaces ```properties spring.config.import=apollo://namespace3, apollo://namespace2, apollo://namespace1 ``` For Spring Boot version 2.4 and above, it also supports loading configuration through Config Data Loader mode Apollo's Config Data Loader also provides a webClient-based http client to replace the original http client, so as to easily extend the http client WebClient can be based on multiple implementations (reactor netty httpclient, jetty reactive httpclient, apache httpclient5), the dependencies to be added are as follows ```xml <dependencies> <dependency> <groupId>com.ctrip.framework.apollo</groupId> <artifactId>apollo-client-config-data</artifactId> <version>1.9.0</version> </dependency> <!-- webclient --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webflux</artifactId> </dependency> <!-- reactor netty httpclient --> <dependency> <groupId>io.projectreactor.netty</groupId> <artifactId>reactor-netty-http</artifactId> </dependency> </dependencies> ``` ```xml <dependencies> <dependency> <groupId>com.ctrip.framework.apollo</groupId> <artifactId>apollo-client-config-data</artifactId> <version>1.9.0</version> </dependency> <!-- webclient --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webflux</artifactId> </dependency> <!-- jetty reactive httpclient --> <dependency> <groupId>org.eclipse.jetty</groupId> <artifactId>jetty-reactive-httpclient</artifactId> </dependency> </dependencies> ``` Spring boot does not specify the version of apache httpclient5, so you need to manually specify the version here ```xml <dependencies> <dependency> <groupId>com.ctrip.framework.apollo</groupId> <artifactId>apollo-client-config-data</artifactId> <version>1.9.0</version> </dependency> <!-- webclient --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webflux</artifactId> </dependency> <!-- apache httpclient5 --> <dependency> <groupId>org.apache.httpcomponents.client5</groupId> <artifactId>httpclient5</artifactId> <version>5.1</version> </dependency> <dependency> <groupId>org.apache.httpcomponents.core5</groupId> <artifactId>httpcore5-reactive</artifactId> <version>5.1</version> </dependency> </dependencies> ``` The default namespace is used here as an

Please refer to 3.2.1.4.3 for the configuration of namespace. ```properties spring.config.import=apollo://application apollo.client.extension.enabled=true ``` Provides a spi implementation of interface `com.ctrip.framework.apollo.config.data.extension.webclient.customizer.spi.ApolloClientWebClientCustomizerFactory` After configuring `apollo.client.extension.enabled=true`, Apollo's Config Data Loader will try to load the spi's implementation class to customize the webClient Spring applications usually use Placeholder to inject configuration in the form of ${someKey:someDefaultValue}, such as ${timeout:100}. The key before the colon is the key, and the default value after the colon. It is recommended to give the default value as much as possible in actual use, so as to avoid runtime errors due to the undefined key. Versions starting from v0.10.0 support automatic update of placeholders at runtime, see . If you need to turn off the automatic update function of placeholder at runtime, you can turn it off in the following two ways: By setting the System Property `apollo.autoUpdateInjectedSpringProperties`, such as passing in `-Dapollo.autoUpdateInjectedSpringProperties=false` at startup By setting the `apollo.autoUpdateInjectedSpringProperties` property in META-INF/app.properties, such as ```properties app.id=SampleApp apollo.autoUpdateInjectedSpringProperties=false ``` Suppose I have a TestXmlBean with two configuration items that need to be injected: ```java public class TestXmlBean { private int timeout; private int batch; public void setTimeout(int timeout) { this.timeout = timeout; } public void setBatch(int batch) { this.batch = batch; } public int getTimeout() { return timeout; } public int getBatch() { return batch; } } ``` Then, I will use the following way to define in XML (assuming that the default application namespace of the application has timeout and batch configuration items): ```xml <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:apollo="http://www.ctrip.com/schema/apollo" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.ctrip.com/schema/apollo http://www.ctrip.com/schema/apollo.xsd"> <apollo:config/> <bean class="com.ctrip.framework.apollo.spring.TestXmlBean"> <property name="timeout" value="${timeout:100}"/> <property name="batch" value="${batch:200}"/> </bean> </beans> ``` Suppose I have a TestJavaConfigBean, which can also be injected using @Value through Java Config: ```java public class TestJavaConfigBean { @Value("${timeout:100}") private int timeout; private int batch; @Value("${batch:200}") public void setBatch(int batch) { this.batch = batch; } public int getTimeout() { return timeout; } public int getBatch() { return batch; } } ``` In the Configuration class, use it in the following way (assuming the default application namespace of the application has `timeout` and `batch` configuration items): ```java @Configuration @EnableApolloConfig public class AppConfig { @Bean public TestJavaConfigBean javaConfigBean() { return new TestJavaConfigBean(); } } ``` Spring Boot provides to inject configuration into bean objects . Apollo also supports this method. The following example will inject `redis.cache.expireSeconds` and `redis.cache.commandTimeout` into the `expireSeconds` and `commandTimeout` fields of SampleRedisConfig respectively. ```java @ConfigurationProperties(prefix = "redis.cache") public class SampleRedisConfig { private int expireSeconds; private int commandTimeout; public void setExpireSeconds(int expireSeconds) { this.expireSeconds = expireSeconds; } public void setCommandTimeout(int commandTimeout) { this.commandTimeout = commandTimeout; } } ``` In the Configuration class, use it in the following way (assuming the default application namespace of the application has `redis.cache.expireSeconds` and `redis.cache.commandTimeout` configuration items): ```java @Configuration @EnableApolloConfig public class AppConfig { @Bean public SampleRedisConfig sampleRedisConfig() { return new SampleRedisConfig(); } } ``` It should be noted that if `@ConfigurationProperties` needs to automatically update the injected value when the Apollo configuration changes, you need to use or . For related code implementation, please refer to and and Apollo also adds several new Annotations to simplify usage in the Spring environment. @ApolloConfig Used to automatically inject the Config object @ApolloConfigChangeListener Used to automatically register ConfigChangeListener @ApolloJsonValue Used to automatically inject the configured json string as an object Example of usage is as follows: ```java public class TestApolloAnnotationBean { @ApolloConfig private Config config; //inject config for namespace application @ApolloConfig("application") private Config anotherConfig; //inject config for namespace application

private Config yetAnotherConfig; //inject config for namespace FX.apollo @ApolloConfig("application.yml") private Config ymlConfig; //inject config for namespace application.yml / ApolloJsonValue annotated on fields example, the default value is specified as empty list - [] <br /> jsonBeanProperty=[{"someString":"hello","someInt":100},{"someString":"world!","someInt":200}] */ @ApolloJsonValue("${jsonBeanProperty:[]}") private List<JsonBean> anotherJsonBeans; @Value("${batch:100}") private int batch; //config change listener for namespace application @ApolloConfigChangeListener private void someOnChange(ConfigChangeEvent changeEvent) { //update injected value of batch if it is changed in Apollo if (changeEvent.isChanged("batch")) { batch = config.getIntProperty("batch", 100); } } //config change listener for namespace application @ApolloConfigChangeListener("application") private void anotherOnChange(ConfigChangeEvent changeEvent) { //do something } //config change listener for namespaces application, FX.apollo and application.yml @ApolloConfigChangeListener({"application", "FX.apollo", "application.yml"}) private void yetAnotherOnChange(ConfigChangeEvent changeEvent) { //do something } //example of getting config from Apollo directly //this will always return the latest value of timeout public int getTimeout() { return config.getIntProperty("timeout", 200); } //example of getting config from injected value //the program needs to update the injected value when batch is changed in Apollo using @ApolloConfigChangeListener shown above public int getBatch() { return this.batch; } private static class JsonBean{ private String someString; private int someInt; } } ``` Use it in the Configuration class as follows: ```java @Configuration @EnableApolloConfig public class AppConfig { @Bean public TestApolloAnnotationBean testApolloAnnotationBean() { return new TestApolloAnnotationBean(); } } ``` In many cases, the application may already have a lot of configuration, such as Spring Boot application, there will be configurations such as bootstrap.properties/yml, application.properties/yml, etc. After the application is connected to Apollo, these configurations can be easily migrated to Apollo. The specific steps are as follows: Create a new project for the application in Apollo Configure `META-INF/app.properties` in the application It is recommended to convert the original configuration to the properties format, and then paste it into the application namespace of the application through the text editing mode provided by Apollo, and publish the configuration If the original format is yml, you can use into properties format If the original is yml and you want to continue to use yml to edit the configuration, you can create a private application.yml namespace, paste all the original configuration into it, and publish the configuration Requires `apollo-client` to be version `1.3.0` and above Delete the original configuration files such as bootstrap.properties/yml, application.properties/yml from the project If you need to keep the local configuration file, it should be noted that some configurations such as `server.port` must ensure that the configuration item has been deleted from the local file Such as: ```properties spring.application.name=reservation-service server.port = 8080 logging.level = ERROR eureka.client.serviceUrl.defaultZone = http://127.0.0.1:8761/eureka/ eureka.client.healthcheck.enabled=true eureka.client.registerWithEureka = true eureka.client.fetchRegistry = true eureka.client.eurekaServiceUrlPollIntervalSeconds = 60 eureka.instance.preferIpAddress = true ``` There is a sample client project in the project: `apollo-demo`, for details, please refer to in section. For more use case demos, please refer to . The above diagram briefly describes the principle of Apollo client implementation. The client and the server maintain a long connection so that it can get the first push of configuration updates. (achieved through Http Long Polling) . The client also regularly pulls the latest configuration of the application from the Apollo Configuration Center server. This is a fallback mechanism to prevent the configuration from being updated due to the failure of the push mechanism. The client will report the local version of the timed pull, so in general, for the timed pull operation, the server will return 304 - Not Modified. Timing frequency defaults to pulling every 5 minutes. Clients can also override this by specifying System Property: `apollo.refreshInterval` at runtime, in

After the client gets the latest configuration of the application from the Apollo Configuration Center server, it will be saved in memory. The client will cache a copy of the configuration obtained from the server in the local file system. In case of service unavailability or network failure, the configuration can still be restored locally. The application can get the latest configuration from the Apollo client, subscribe to configuration update notifications. Apollo client also supports local development mode, which is mainly used when the development environment cannot connect to Apollo server, such as doing related function development on cruise ships or airplanes. In local development mode, Apollo will only read configuration information from local files, not from Apollo server. You can enable Apollo local development mode by following the steps below. Modify the `/opt/settings/server.properties` (Mac/Linux) or `C:\opt\settings\server.properties` (Windows) file to set the env to Local: ```properties env=Local ``` For more ways to configure the environment, please refer to In local development mode, Apollo client will read the files from local, so we need to prepare the configuration file beforehand. The local configuration directory is located at. Mac/Linux*: /opt/data/{appId}/config-cache Windows*: C:\opt\data\\\{appId}\config-cache The appId is the appId of the application, e.g. 100004458. Please make sure the directory exists and the application has read access to it. [Tip] The recommended way is to use Apollo in normal mode first, so that Apollo will automatically create the directory and generate the configuration file under it. Local configuration files need to be placed in the local configuration directory according to a certain file name format, which is as follows. _{appId}+{cluster}+{namespace}.properties_ AppId is the application's own appId, such as 100004458 Cluster is the cluster used by the application, generally in local mode without configuration, it is default Namespace is the configuration `namespace` used by the `application`, usually `application` The content of the file is stored in properties format, for example, if there are two keys, one is request.timeout and the other is batch, then the content of the file is in the following format. ```properties request.timeout=2000 batch=2000 ``` In local development mode, Apollo does not monitor the file content for changes in real time, so if you modify the configuration, you need to restart the application to take effect. The `apollo-mockserver` has been added since version 1.1.0, so that it can well support scenarios where mock configuration is required for unit testing, using the following methods. ```xml <dependency> <groupId>com.ctrip.framework.apollo</groupId> <artifactId>apollo-mockserver</artifactId> <version>1.7.0</version> </dependency> ``` The file name convention is `mockdata-{namespace}.properties` For more usage demos, see and . ```java @RunWith(SpringJUnit4ClassRunner.class) @SpringApplicationConfiguration(classes = TestConfiguration.class) public class SpringIntegrationTest { // startup apollo's mockserver @ClassRule public static EmbeddedApollo embeddedApollo = new EmbeddedApollo(); @Test @DirtiesContext // This annotation is necessary because configuration injection can mess up the application context public void testPropertyInject(){ assertEquals("value1", testBean.key1); assertEquals("value2", testBean.key2); } @Test @DirtiesContext public void testListenerTriggeredByAdd() throws InterruptedException, ExecutionException, TimeoutException { String otherNamespace = "othernamespace"; embeddedApollo.addOrModifyPropery(otherNamespace,"someKey","someValue"); ConfigChangeEvent changeEvent = testBean.futureData.get(5000, TimeUnit.MILLISECONDS); assertEquals(otherNamespace, changeEvent.getNamespace()); assertEquals("someValue", changeEvent.getChange("someKey").getNewValue()); } @EnableApolloConfig("application") @Configuration static class TestConfiguration{ @Bean public TestBean testBean(){ return new TestBean(); } } static class TestBean{ @Value("${key1:default}") String key1; @Value("${key2:default}") String key2; SettableFuture<ConfigChangeEvent> futureData = SettableFuture.create(); @ApolloConfigChangeListener("othernamespace") private void onChange(ConfigChangeEvent changeEvent) { futureData.set(changeEvent); } } } ``` from version 2.1.0 To satisfy users' different demands on ConfigService load balancing algorithm when using apollo-client, we provide spi since version 2.1.0 The interface is `com.ctrip.framework.apollo.spi.ConfigServiceLoadBalancerClient`. The Input is multiple ConfigServices returned by meta server, and the output is a ConfigService selected. The default service provider is `com.ctrip.framework.apollo.spi.RandomConfigServiceLoadBalancerClient`, which chooses one ConfigService from multiple ConfigServices using random strategy .