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tfnotify

tfnotify parses Terraform commands' execution result and applies it to an arbitrary template and then notifies it to GitHub comments etc.

Motivation

There are commands such as plan and apply on Terraform command, but many developers think they would like to check if the execution of those commands succeeded. Terraform commands are often executed via CI like Circle CI, but in that case you need to go to the CI page to check it. This is very troublesome. It is very efficient if you can check it with GitHub comments or Slack etc. You can do this by using this command.

Installation

Grab the binary from GitHub Releases (Recommended)

$ go get -u github.com/mercari/tfnotify

What tfnotify does

Parse the execution result of Terraform
Bind parsed results to Go templates
Notify it to any platform (e.g. GitHub) as you like

Detailed specifications such as templates and notification destinations can be customized from the configuration files (described later).

Usage

Basic

tfnotify is just CLI command. So you can run it from your local after grabbing the binary.

Basically tfnotify waits for the input from Stdin. So tfnotify needs to pipe the output of Terraform command like the following:

$ terraform plan | tfnotify plan

For plan command, you also need to specify plan as the argument of tfnotify. In the case of apply, you need to do apply. Currently supported commands can be checked with tfnotify --help.

Configurations

When running tfnotify, you can specify the configuration path via --config option (if it's omitted, it defaults to {.,}tfnotify.y{,a}ml).

The example settings of GitHub and GitHub Enterprise, Slack, Typetalk are as follows. Incidentally, there is no need to replace TOKEN string such as $GITHUB_TOKEN with the actual token. Instead, it must be defined as environment variables in CI settings.

template of Go can be used for template. The templates can be used in tfnotify.yaml are as follows:

Placeholder	Usage
`{{ .Title }}`	Like `## Plan result`
`{{ .Message }}`	A string that can be set from CLI with `--message` option
`{{ .Result }}`	Matched result by parsing like `Plan: 1 to add` or `No changes`
`{{ .Body }}`	The entire of Terraform execution result
`{{ .Link }}`	The link of the build page on CI

On GitHub, tfnotify can also put a warning message if the plan result contains resource deletion (optional).

Template Examples

<details> <summary>For GitHub</summary>

---
ci: circleci
notifier:
  github:
    token: $GITHUB_TOKEN
    repository:
      owner: "mercari"
      name: "tfnotify"
terraform:
  fmt:
    template: |
      {{ .Title }}

      {{ .Message }}

      {{ .Result }}

      {{ .Body }}
  plan:
    template: |
      {{ .Title }} <sup>[CI link]( {{ .Link }} )</sup>
      {{ .Message }}
      {{if .Result}}
      <pre><code>{{ .Result }}
      </pre></code>
      {{end}}
      <details><summary>Details (Click me)</summary>

      <pre><code>{{ .Body }}
      </pre></code></details>
  apply:
    template: |
      {{ .Title }}
      {{ .Message }}
      {{if .Result}}
      <pre><code>{{ .Result }}
      </pre></code>
      {{end}}
      <details><summary>Details (Click me)</summary>

      <pre><code>{{ .Body }}
      </pre></code></details>

If you would like to let tfnotify warn the resource deletion, add when_destroy configuration as below.

---
# ...
terraform:
  # ...
  plan:
    template: |
      {{ .Title }} <sup>[CI link]( {{ .Link }} )</sup>
      {{ .Message }}
      {{if .Result}}
      <pre><code>{{ .Result }}
      </pre></code>
      {{end}}
      <details><summary>Details (Click me)</summary>

      <pre><code>{{ .Body }}
      </pre></code></details>
    when_destroy:
      template: |
        ## :warning: WARNING: Resource Deletion will happen :warning:

        This plan contains **resource deletion**. Please check the plan result very carefully!
  # ...

You can also let tfnotify add a label to PRs depending on the terraform plan output result. Currently, this feature is for Github labels only.

---
# ...
terraform:
  # ...
  plan:
    template: |
      {{ .Title }} <sup>[CI link]( {{ .Link }} )</sup>
      {{ .Message }}
      {{if .Result}}
      <pre><code>{{ .Result }}
      </pre></code>
      {{end}}
      <details><summary>Details (Click me)</summary>

      <pre><code>{{ .Body }}
      </pre></code></details>
    when_add_or_update_only:
      label: "add-or-update"
    when_destroy:
      label: "destroy"
    when_no_changes:
      label: "no-changes"
    when_plan_error:
      label: "error"
  # ...

Sometimes you may want not to HTML-escape Terraform command outputs. For example, when you use code block to print command output, it's better to use raw characters instead of character references (e.g. -/+ -> -/+, " -> ").

You can disable HTML escape by adding use_raw_output: true configuration. With this configuration, Terraform doesn't HTML-escape any Terraform output.

---
# ...
terraform:
  use_raw_output: true
  # ...
  plan:
    template: |
      {{ .Title }} <sup>[CI link]( {{ .Link }} )</sup>
      {{ .Message }}
      {{if .Result}}
      ```
      {{ .Result }}
      ```
      {{end}}
      <details><summary>Details (Click me)</summary>

      ```
      {{ .Body }}
      ```
  # ...

</details> <details> <summary>For GitHub Enterprise</summary>

---
ci: circleci
notifier:
  github:
    token: $GITHUB_TOKEN
    base_url: $GITHUB_BASE_URL # Example: https://github.example.com/api/v3
    repository:
      owner: "mercari"
      name: "tfnotify"
terraform:
  fmt:
    template: |
      {{ .Title }}

      {{ .Message }}

      {{ .Result }}

      {{ .Body }}
  plan:
    template: |
      {{ .Title }} <sup>[CI link]( {{ .Link }} )</sup>
      {{ .Message }}
      {{if .Result}}
      <pre><code>{{ .Result }}
      </pre></code>
      {{end}}
      <details><summary>Details (Click me)</summary>

      <pre><code>{{ .Body }}
      </pre></code></details>
  apply:
    template: |
      {{ .Title }}
      {{ .Message }}
      {{if .Result}}
      <pre><code>{{ .Result }}
      </pre></code>
      {{end}}
      <details><summary>Details (Click me)</summary>

      <pre><code>{{ .Body }}
      </pre></code></details>

</details> <details> <summary>For GitLab</summary>

---
ci: gitlabci
notifier:
  gitlab:
    token: $GITLAB_TOKEN
    base_url: $GITLAB_BASE_URL
    repository:
      owner: "mercari"
      name: "tfnotify"
terraform:
  fmt:
    template: |
      {{ .Title }}

      {{ .Message }}

      {{ .Result }}

      {{ .Body }}
  plan:
    template: |
      {{ .Title }} <sup>[CI link]( {{ .Link }} )</sup>
      {{ .Message }}
      {{if .Result}}
      <pre><code> {{ .Result }}
      </pre></code>
      {{end}}
      <details><summary>Details (Click me)</summary>
      <pre><code> {{ .Body }}
      </pre></code></details>
  apply:
    template: |
      {{ .Title }}
      {{ .Message }}
      {{if .Result}}
      <pre><code> {{ .Result }}
      </pre></code>
      {{end}}
      <details><summary>Details (Click me)</summary>
      <pre><code> {{ .Body }}
      </pre></code></details>

</details> <details> <summary>For Slack</summary>

---
ci: circleci
notifier:
  slack:
    token: $SLACK_TOKEN
    channel: $SLACK_CHANNEL_ID
    bot: $SLACK_BOT_NAME
terraform:
  plan:
    template: |
      {{ .Message }}
      {{if .Result}}
      ```
      {{ .Result }}
      ```
      {{end}}
      ```
      {{ .Body }}
      ```

You can disable HTML escape by adding use_raw_output: true configuration. With this configuration, Terraform doesn't HTML-escape any Terraform output.

---
# ...
terraform:
  use_raw_output: true
  # ...
  plan:
  # ...

</details> <details> <summary>For Typetalk</summary>

---
ci: circleci
notifier:
  typetalk:
    token: $TYPETALK_TOKEN
    topic_id: $TYPETALK_TOPIC_ID
terraform:
  plan:
    template: |
      {{ .Message }}
      {{if .Result}}
      ```
      {{ .Result }}
      ```
      {{end}}
      ```
      {{ .Body }}
      ```

</details>

Supported CI

Currently, supported CI are here:

Circle CI
Travis CI
AWS CodeBuild
TeamCity
Drone
Jenkins
GitLab CI
GitHub Actions
Google Cloud Build

Private Repository Considerations

GitHub private repositories require the repo and write:discussion permissions.

Jenkins Considerations

Plugin
- Git Plugin
Environment Variable
- PULL_REQUEST_NUMBER or PULL_REQUEST_URL are required to set by user for Pull Request Usage

Google Cloud Build Considerations

These environment variables are needed to be set using substitutions
- COMMIT_SHA
- BUILD_ID
- PROJECT_ID
- _PR_NUMBER
- _REGION
Recommended trigger events
- terraform plan: Pull request
- terraform apply: Push to branch

Committers

Masaki ISHIYAMA (@b4b4r07)

Contribution

Please read the CLA below carefully before submitting your contribution.

https://www.mercari.com/cla/

License

Licensed under the MIT License.