Package: kubragen
KubraGen: programmatic Kubernetes YAML generatorOverviewKubraGen is a Kubernetes YAML generator library that makes it possible to generate
configurations using the full power of the Python programming language.Using plugins (called Builders), it is possible to include libraries that know how to configure
specific services, like Prometheus, RabbitMQ, Traefik, etc.Thejsonpatchextlibrary (an extension ofjsonpatch) is used to make it possible to check and modify the output
objects in any way without accessing the returned dicts directly, including merging dicts with thedeepmergelibrary.See source code for examplesWebsite:https://github.com/RangelReale/kubragenRepository:https://github.com/RangelReale/kubragen.gitDocumentation:https://kubragen.readthedocs.org/PyPI:https://pypi.python.org/pypi/kubragenSamplesReal-world samples:kubragen_samplesBuildersRabbitMQ:kg_rabbitmqTraefik 2:kg_traefik2Keycloak:kg_keycloakIngress NGINX:kg_ingressnginxPrometheus:kg_prometheusGrafana:kg_grafanaNode Exporter:kg_nodeexporterKube State Metrics:kg_kubestatemetricsLoki:kg_lokiPromtail:kg_promtailKube Resource Report:kg_kuberesourcereportRabbitMQ (Online YAML download):kg_rabbitmqonlinePrometheus Stack (Prometheus, Grafana, Node Exporter, Kube State Metrics):kg_prometheusstackEFK Stack (Elasticsearch, Fluentd, Kibana):kg_efkLoki Stack (Loki, Promtail, Grafana):kg_lokistackProvidersCore (Amazon EKS, Google GKE, DigitalOcean Kubernetes, K3D, KIND):kgpr_corePluginsConfig Renderer - TOML:kgp_configrendertomlExampleThis example is purposeful convoluted to illustrate the many features of the library.fromkubragenimportKubraGenfromkubragen.constsimportPROVIDER_GOOGLE,PROVIDERSVC_GOOGLE_GKEfromkubragen.dataimportValueDatafromkubragen.helperimportQuotedStrfromkubragen.jsonpatchimportFilterJSONPatches_Apply,FilterJSONPatch,ObjectFilterfromkubragen.kdataimportKData_Secretfromkubragen.objectimportObjectfromkubragen.optionimportOptionRootfromkubragen.optionsimportOptionsfromkubragen.outputimportOutputProject,OD_FileTemplate,OutputFile_ShellScript,OutputFile_Kubernetes,\OutputDriver_Printfromkubragen.providerimportProviderfromkg_rabbitmqimportRabbitMQBuilder,RabbitMQOptionskg=KubraGen(provider=Provider(PROVIDER_GOOGLE,PROVIDERSVC_GOOGLE_GKE),options=Options({'namespaces':{'default':'app-default','monitoring':'app-monitoring',},}))out=OutputProject(kg)shell_script=OutputFile_ShellScript('create_gke.sh')out.append(shell_script)shell_script.append('set -e')## OUTPUTFILE: app-namespace.yaml#file=OutputFile_Kubernetes('app-namespace.yaml')out.append(file)file.append(FilterJSONPatches_Apply([Object({'apiVersion':'v1','kind':'Namespace','metadata':{'name':'app-default','annotations':{'will-not-output':ValueData(value='anything',enabled=False),}},},name='ns-default',source='app'),Object({'apiVersion':'v1','kind':'Namespace','metadata':{'name':'app-monitoring',},},name='ns-monitoring',source='app'),],jsonpatches=[FilterJSONPatch(filters=ObjectFilter(names=['ns-monitoring']),patches=[{'op':'add','path':'/metadata/annotations','value':{'kubragen.github.io/patches':QuotedStr('true'),}},])]))shell_script.append(OD_FileTemplate(f'kubectl apply -f ${{FILE_{file.fileid}}}'))shell_script.append(f'kubectl config set-context --current --namespace=app-default')## SETUP: rabbitmq#rabbitmq_config=RabbitMQBuilder(kubragen=kg,options=RabbitMQOptions({'namespace':OptionRoot('namespaces.monitoring'),'basename':'myrabbit','config':{'erlang_cookie':KData_Secret(secretName='app-global-secrets',secretData='erlang_cookie'),'enable_prometheus':True,'prometheus_annotation':True,'authorization':{'serviceaccount_create':True,'roles_create':True,'roles_bind':True,},},'kubernetes':{'volumes':{'data':{'persistentVolumeClaim':{'claimName':'rabbitmq-storage-claim'}}},'resources':{'statefulset':{'requests':{'cpu':'150m','memory':'300Mi'},'limits':{'cpu':'300m','memory':'450Mi'},},},}})).jsonpatches([FilterJSONPatch(filters={'names':[RabbitMQBuilder.BUILDITEM_SERVICE]},patches=[{'op':'check','path':'/spec/ports/0/name','cmp':'equals','value':'http'},{'op':'replace','path':'/spec/type','value':'LoadBalancer'},]),])rabbitmq_config.ensure_build_names(rabbitmq_config.BUILD_ACCESSCONTROL,rabbitmq_config.BUILD_CONFIG,rabbitmq_config.BUILD_SERVICE)## OUTPUTFILE: rabbitmq-config.yaml#file=OutputFile_Kubernetes('rabbitmq-config.yaml')out.append(file)file.append(rabbitmq_config.build(rabbitmq_config.BUILD_ACCESSCONTROL,rabbitmq_config.BUILD_CONFIG))shell_script.append(OD_FileTemplate(f'kubectl apply -f ${{FILE_{file.fileid}}}'))## OUTPUTFILE: rabbitmq.yaml#file=OutputFile_Kubernetes('rabbitmq.yaml')out.append(file)file.append(rabbitmq_config.build(rabbitmq_config.BUILD_SERVICE))shell_script.append(OD_FileTemplate(f'kubectl apply -f ${{FILE_{file.fileid}}}'))## OUTPUT#out.output(OutputDriver_Print())# out.output(OutputDriver_Directory('/tmp/app-gke'))Output:****** BEGIN FILE: 001-app-namespace.yaml ********
apiVersion: v1
kind: Namespace
metadata:
  name: app-default
  annotations: {}
---
apiVersion: v1
kind: Namespace
metadata:
  name: app-monitoring
  annotations:
    kubragen.github.io/patches: 'true'

****** END FILE: 001-app-namespace.yaml ********
****** BEGIN FILE: 002-rabbitmq-config.yaml ********
apiVersion: v1
kind: ServiceAccount
metadata:
  name: myrabbit
  namespace: app-monitoring
---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1beta1
<...more...>
****** END FILE: 002-rabbitmq-config.yaml ********
****** BEGIN FILE: 003-rabbitmq.yaml ********
apiVersion: v1
kind: Service
metadata:
  name: myrabbit-headless
  namespace: app-monitoring
spec:
  clusterIP: None
<...more...>
****** END FILE: 003-rabbitmq.yaml ********
****** BEGIN FILE: create_gke.sh ********
#!/bin/bash

set -e
kubectl apply -f 001-app-namespace.yaml
kubectl config set-context --current --namespace=app-default
kubectl apply -f 002-rabbitmq-config.yaml
kubectl apply -f 003-rabbitmq.yaml

****** END FILE: create_gke.sh ********Design PhilosophyAs the generated Kubernetes files can have critical consequences, the library is designed to fail on the minimal
possibility of error, and also gives tools to users of the library to check any generated value for critical
options, using thejsonpatchextlibrary to check the data output by the builders.To minimize the use of dict concatenation, a special typekubragen.data.Datacan be used anywhere in the object,
and it has ais_enabled()method that removes the value (and its key if it is contained in a dict/list)
if it returns False.Only YAML is supported by the library, it is not possible to generate JSON directly at the moment.AuthorRangel Reale (rangelreale@gmail.com)