早前，GitHub 发布 GitHub Actions 项目，开发者可通过 GitHub Actions 存储和搜索代码，部分代码可直接运行。本文尝试使用 AWS Lambda 和 API Gateway 作为基本 API，编写应用程序原型并用名为 gourmet 的容器运行函数，虽然这可能不会让代码易于管理，但至少不需要写 API 或者 Web 应用程序。
正如 Lambda 函数在 AWS 中运行一样，Github Actions 是一种强大的管理方式，可直接扩展应用。使用 AWS Lambda，可将代码挂接到几乎任何事件上，比如 EC2 创建、终止、DNS 记录更改等，不需要运行服务器，只需加载代码就能正常工作。
本文作者针对此做了一些尝试，但需要 CI 服务器。为了拥有可测试的 kubernetes 集群，作者自建私有存储库，目前因内部有些混乱暂不准备开源。
无论如何，以下是项目文件夹:
├── .github│ ├── actions│ │ ├── deploy│ │ │ ├── deploy│ │ │ └── Dockerfile│ │ └── dryrun│ │ ├── Dockerfile│ │ └── dryrun│ └── main.workflow└── kubernetes ├── digitalocean.yaml ├── external-dns.yaml ├── micro.yaml ├── namespaces.yaml ├── nginx.yaml └── openvpn.yaml
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kubernetes 目录包含集群安装的所有东西。对于此存储库的每次新推送，需要检查是否可用命令 kubectl apply -f./kubernetes --dryrun 将其应用于 kubernetes 集群，并且当合并 PR 时，应用更改。
因此，作者在.github/main.workflow 中创办了工作流：
## Workflow defines what we want to call a set of actions.## For every new push check if the changes can be applied to kubernetes ## using the action called: kubectl dryrunworkflow "after a push check if they apply to kubernetes" { on = "push" resolves = ["kubectl dryrun"]}## When a PR is merged trigger the action: kubectl deploy. To apply the new code to master.workflow "on merge to master deploy on kubernetes" { on = "pull_request" resolves = ["kubectl deploy"]}## This is the action that checks if the push can be applied to kubernetesaction "kubectl dryrun" { uses = "./.github/actions/dryrun" secrets = ["KUBECONFIG"]}## This is the action that applies the change to kubernetesaction "kubectl deploy" { uses = "./.github/actions/deploy" secrets = ["KUBECONFIG"]}
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secrets 是一组环境变量，可从外部设置值。如果帐户启用 GitHub Action，则每个存储库的 Setting 都会有一个名为 secrets 的新标签。
本例，作者将 KUBECONFIG 设置为 kubeconfig 文件的 base64，允许 GitHub Action 授权给 Kubernetes 集群。
两个操作类似，第一个操作位于 .github/actions/dryrun 目录：
├── .github ├── actions └── dryrun ├── Dockerfile └── dryrun
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包含一个 Dockerfile
FROM alpine:latest
## The action name displayed by GitHubLABEL "com.github.actions.name"="kubectl dryrun"## The description for the actionLABEL "com.github.actions.description"="Check the kubernetes change to apply."## https://developer.github.com/actions/creating-github-actions/creating-a-docker-container/#supported-feather-iconsLABEL "com.github.actions.icon"="check"## The color of the action iconLABEL "com.github.actions.color"="blue"
RUN apk add --no-cache \ bash \ ca-certificates \ curl \ git \ jq
RUN curl -L -o /usr/bin/kubectl https://storage.googleapis.com/kubernetes-release/release/v1.13.0/bin/linux/amd64/kubectl && \ chmod +x /usr/bin/kubectl && \ kubectl version --client
COPY dryrun /usr/bin/dryrunCMD ["dryrun"]
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如上所示，只需要一个 Dockerfile，工作原理和 docker 类似。Cmd dryrun 在这里是复制的 bash 脚本:
#!/bin/bash
main(){ echo ">>>> Action started" # Decode the secret passed by the action and paste the config in a file. echo $KUBECONFIG | base64 -d > ./kubeconfig.yaml echo ">>>> kubeconfig created" # Check if the kubernetes directory has change diff=$(git diff --exit-code HEAD~1 HEAD ./kubernetes) if [ $? -eq 1 ]; then echo ">>>> Detected a change inside the kubernetes directory" # Apply the changes with --dryrun just to validate them kubectl apply --kubeconfig ./kubeconfig.yaml --dry-run -f ./kubernetes else echo ">>>> No changed detected inside the ./kubernetes folder. Nothing to do." fi}
main "$@"
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第二个操作和此几乎一样，Dockerfile 是相同的，但 CMD 看起来是这样的:
#!/bin/bash
main(){ # Decode the secret passed by the action and paste the config in a file. echo $KUBECONFIG | base64 -d > ./kubeconfig.yaml # Check if it is an event generated by the PR is a merge merged=$(jq --raw-output .pull_request.merged "$GITHUB_EVENT_PATH") # Retrieve the base branch for the PR because I would like to apply only PR merged to master baseRef=$(jq --raw-output .pull_request.base.ref "$GITHUB_EVENT_PATH")
if [[ "$merged" == "true" ]] && [[ "$baseRef" == "master" ]]; then echo ">>>> PR merged into master. Shipping to k8s!" kubectl apply --kubeconfig ./kubeconfig.yaml -f ./kubernetes else echo ">>>> Nothing to do here!" fi}
main "$@"
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除此之外，工作流文件还有一个生成器，似乎效果不错。secrets 允许开箱即用，并与第三方服务集成，也可用 bash 做任何想做的事情！
参考链接：https://gianarb.it/blog/kubernetes-github-action
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