Chapter 99. Exec Component Available as of Camel version 2.3 The exec component can be used to execute system commands. 99.1. Dependencies Maven users need to add the following dependency to their pom.xml <dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-exec</artifactId> <version>USD{camel-version}</version> </dependency> where USD{camel-version } must be replaced by the actual version of Camel (2.3.0 or higher). 99.2. URI format exec://executable[?options] where executable is the name, or file path, of the system command that will be executed. If executable name is used (e.g. exec:java ), the executable must in the system path. 99.3. URI options The Exec component has no options. The Exec endpoint is configured using URI syntax: with the following path and query parameters: 99.3.1. Path Parameters (1 parameters): Name Description Default Type executable Required Sets the executable to be executed. The executable must not be empty or null. String 99.3.2. Query Parameters (8 parameters): Name Description Default Type args (producer) The arguments may be one or many whitespace-separated tokens. String binding (producer) A reference to a org.apache.commons.exec.ExecBinding in the Registry. ExecBinding commandExecutor (producer) A reference to a org.apache.commons.exec.ExecCommandExecutor in the Registry that customizes the command execution. The default command executor utilizes the commons-exec library, which adds a shutdown hook for every executed command. ExecCommandExecutor outFile (producer) The name of a file, created by the executable, that should be considered as its output. If no outFile is set, the standard output (stdout) of the executable will be used instead. String timeout (producer) The timeout, in milliseconds, after which the executable should be terminated. If execution has not completed within the timeout, the component will send a termination request. long useStderrOnEmptyStdout (producer) A boolean indicating that when stdout is empty, this component will populate the Camel Message Body with stderr. This behavior is disabled (false) by default. false boolean workingDir (producer) The directory in which the command should be executed. If null, the working directory of the current process will be used. String synchronous (advanced) Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported). false boolean 99.4. Spring Boot Auto-Configuration The component supports 2 options, which are listed below. Name Description Default Type camel.component.exec.enabled Enable exec component true Boolean camel.component.exec.resolve-property-placeholders Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders. true Boolean 99.5. Message headers The supported headers are defined in org.apache.camel.component.exec.ExecBinding . Name Type Message Description ExecBinding.EXEC_COMMAND_EXECUTABLE String in The name of the system command that will be executed. Overrides executable in the URI. ExecBinding.EXEC_COMMAND_ARGS java.util.List<String> in Command-line arguments to pass to the executed process. The arguments are used literally - no quoting is applied. Overrides any existing args in the URI. ExecBinding.EXEC_COMMAND_ARGS String in Camel 2.5: The arguments of the executable as a Single string where each argument is whitespace separated (see args in URI option). The arguments are used literally, no quoting is applied. Overrides any existing args in the URI. ExecBinding.EXEC_COMMAND_OUT_FILE String in The name of a file, created by the executable, that should be considered as its output. Overrides any existing outFile in the URI. ExecBinding.EXEC_COMMAND_TIMEOUT long in The timeout, in milliseconds, after which the executable should be terminated. Overrides any existing timeout in the URI. ExecBinding.EXEC_COMMAND_WORKING_DIR String in The directory in which the command should be executed. Overrides any existing workingDir in the URI. ExecBinding.EXEC_EXIT_VALUE int out The value of this header is the exit value of the executable. Non-zero exit values typically indicate abnormal termination. Note that the exit value is OS-dependent. ExecBinding.EXEC_STDERR java.io.InputStream out The value of this header points to the standard error stream (stderr) of the executable. If no stderr is written, the value is null . ExecBinding.EXEC_USE_STDERR_ON_EMPTY_STDOUT boolean in Indicates that when stdout is empty, this component will populate the Camel Message Body with stderr . This behavior is disabled ( false ) by default. 99.6. Message body If the Exec component receives an in message body that is convertible to java.io.InputStream , it is used to feed input to the executable via its stdin. After execution, the message body is the result of the execution,- that is, an org.apache.camel.components.exec.ExecResult instance containing the stdout, stderr, exit value, and out file. This component supports the following ExecResult type converters for convenience: From To ExecResult java.io.InputStream ExecResult String ExecResult byte [] ExecResult org.w3c.dom.Document If an out file is specified (in the endpoint via outFile or the message headers via ExecBinding.EXEC_COMMAND_OUT_FILE ), converters will return the content of the out file. If no out file is used, then this component will convert the stdout of the process to the target type. For more details, please refer to the usage examples below. 99.7. Usage examples 99.7.1. Executing word count (Linux) The example below executes wc (word count, Linux) to count the words in file /usr/share/dict/words . The word count (output) is written to the standard output stream of wc . from("direct:exec") .to("exec:wc?args=--words /usr/share/dict/words") .process(new Processor() { public void process(Exchange exchange) throws Exception { // By default, the body is ExecResult instance assertIsInstanceOf(ExecResult.class, exchange.getIn().getBody()); // Use the Camel Exec String type converter to convert the ExecResult to String // In this case, the stdout is considered as output String wordCountOutput = exchange.getIn().getBody(String.class); // do something with the word count } }); 99.7.2. Executing java The example below executes java with 2 arguments: -server and -version , provided that java is in the system path. from("direct:exec") .to("exec:java?args=-server -version") The example below executes java in c:\temp with 3 arguments: -server , -version and the sytem property user.name . from("direct:exec") .to("exec:c:/program files/jdk/bin/java?args=-server -version -Duser.name=Camel&workingDir=c:/temp") 99.7.3. Executing Ant scripts The following example executes Apache Ant (Windows only) with the build file CamelExecBuildFile.xml , provided that ant.bat is in the system path, and that CamelExecBuildFile.xml is in the current directory. from("direct:exec") .to("exec:ant.bat?args=-f CamelExecBuildFile.xml") In the example, the ant.bat command redirects its output to CamelExecOutFile.txt with -l . The file CamelExecOutFile.txt is used as the out file with outFile=CamelExecOutFile.txt . The example assumes that ant.bat is in the system path, and that CamelExecBuildFile.xml is in the current directory. from("direct:exec") .to("exec:ant.bat?args=-f CamelExecBuildFile.xml -l CamelExecOutFile.txt&outFile=CamelExecOutFile.txt") .process(new Processor() { public void process(Exchange exchange) throws Exception { InputStream outFile = exchange.getIn().getBody(InputStream.class); assertIsInstanceOf(InputStream.class, outFile); // do something with the out file here } }); 99.7.4. Executing echo (Windows) Commands such as echo and dir can be executed only with the command interpreter of the operating system. This example shows how to execute such a command - echo - in Windows. from("direct:exec").to("exec:cmd?args=/C echo echoString") 99.8. See Also Configuring Camel Component Endpoint Getting Started

Commands:
<dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-exec</artifactId> <version>USD{camel-version}</version> </dependency>
exec://executable[?options]
exec:executable
from("direct:exec") .to("exec:wc?args=--words /usr/share/dict/words") .process(new Processor() { public void process(Exchange exchange) throws Exception { // By default, the body is ExecResult instance assertIsInstanceOf(ExecResult.class, exchange.getIn().getBody()); // Use the Camel Exec String type converter to convert the ExecResult to String // In this case, the stdout is considered as output String wordCountOutput = exchange.getIn().getBody(String.class); // do something with the word count } });
from("direct:exec") .to("exec:java?args=-server -version")
from("direct:exec") .to("exec:c:/program files/jdk/bin/java?args=-server -version -Duser.name=Camel&workingDir=c:/temp")
from("direct:exec") .to("exec:ant.bat?args=-f CamelExecBuildFile.xml")
from("direct:exec") .to("exec:ant.bat?args=-f CamelExecBuildFile.xml -l CamelExecOutFile.txt&outFile=CamelExecOutFile.txt") .process(new Processor() { public void process(Exchange exchange) throws Exception { InputStream outFile = exchange.getIn().getBody(InputStream.class); assertIsInstanceOf(InputStream.class, outFile); // do something with the out file here } });
from("direct:exec").to("exec:cmd?args=/C echo echoString")