github-comment

README

github-comment

CLI to create a GitHub comment with GitHub REST API

$ github-comment post -template test

$ github-comment exec -- go test ./...

Note

• Currently, github-comment doesn't support GitHub Enterprise

Install

Please download a binary from the release page.

$ github-comment --version
$ github-comment --help

Getting Started

Please prepare a GitHub access token. https://github.com/settings/tokens

github-comment provides three subcommands.

• init: generate a configuration file template
• post: create a comment
• exec: execute a shell command and create a comment according to the command result

post

Let's create a simple comment. Please change the parameter properly.

$ github-comment post -token <your GitHub personal access token> -org suzuki-shunsuke -repo github-comment -pr 1 -template test

https://github.com/suzuki-shunsuke/github-comment/pull/1#issuecomment-601501451

You can pass the API token from the environment variable GITHUB_TOKEN or GITHUB_ACCESS_TOKEN too. Then we sent a comment test to the pull request https://github.com/suzuki-shunsuke/github-comment/pull/1 . Instead of pull request, we can send a comment to a commit

$ github-comment post -org suzuki-shunsuke -repo github-comment -sha1 36b1ade9740768f3645c240d487b53bee9e42702 -template test

https://github.com/suzuki-shunsuke/github-comment/commit/36b1ade9740768f3645c240d487b53bee9e42702#commitcomment-37933181

The template is rendered with Go's text/template.

You can write the template in the configuration file.

.github-comment.yml

post:
  default:
    template: |
      {{.Org}}/{{.Repo}} test
  hello:
    template: |
      hello world

If the argument -template is given, the configuration file is ignored. We can define multiple templates in the configuration file and specify the template by the argument -template-key (-k).

$ github-comment post -k hello

If -template and -template-key aren't set, the template default is used.

exec

Let's add the following configuration in the configuration file.

exec:
  hello:
    - when: true
      template: |
        exit code: {{.ExitCode}}

        ```
        $ {{.Command}}
        ```

        Stdout:

        ```
        {{.Stdout}}
        ```

        Stderr:

        ```
        {{.Stderr}}
        ```

        CombinedOutput:

        ```
        {{.CombinedOutput}}
        ```

Then run a command and send the result as a comment.

$ github-comment exec -org suzuki-shunsuke -repo github-comment -pr 1 -k hello -- bash -c "echo foo; echo bar >&2; echo zoo"
bar
foo
zoo

https://github.com/suzuki-shunsuke/github-comment/pull/1#issuecomment-601503124

Let's send the comment only if the command is failed. Update the above configuration.

exec:
  hello:
    - when: ExitCode != 0
      template: |
        ...

Run the above command again, then the command wouldn't be created.

If the command is failed, then the comment is created.

$ github-comment exec -org suzuki-shunsuke -repo github-comment -pr 1 -k hello -- curl -f https://github.com/suzuki-shunsuke/not_found
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
curl: (22) The requested URL returned error: 404 Not Found
exit status 22

https://github.com/suzuki-shunsuke/github-comment/pull/1#issuecomment-601505610

You can change the template by the command result.

exec:
  hello:
    - when: ExitCode != 0
      template: |
        command is failed
    - when: ExitCode == 0
      template: |
        command is succeeded

By dont_comment, you can define the condition which the message isn't created.

exec:
  hello:
    - when: ExitCode != 0
      dont_comment: true
    - when: true
      template: |
        Hello, world

Usage

$ github-comment help
NAME:
   github-comment - post a comment to GitHub

USAGE:
   github-comment [global options] command [command options] [arguments...]

VERSION:
   1.9.0

COMMANDS:
   post     post a comment
   exec     execute a command and post the result as a comment
   init     scaffold a configuration file if it doesn't exist
   help, h  Shows a list of commands or help for one command

GLOBAL OPTIONS:
   --help, -h     show help (default: false)
   --version, -v  print the version (default: false)

$ github-comment help post
NAME:
   github-comment post - post a comment

USAGE:
   github-comment post [command options] [arguments...]

OPTIONS:
   --org value                     GitHub organization name
   --repo value                    GitHub repository name
   --token value                   GitHub API token [$GITHUB_TOKEN, $GITHUB_ACCESS_TOKEN]
   --sha1 value                    commit sha1
   --template value                comment template
   --template-key value, -k value  comment template key (default: "default")
   --config value                  configuration file path
   --pr value                      GitHub pull request number (default: 0)
   --var value                     template variable
   --dry-run                       output a comment to standard error output instead of posting to GitHub (default: false)
   --skip-no-token, -n             works like dry-run if the GitHub Access Token isn't set (default: false) [$GITHUB_COMMENT_SKIP_NO_TOKEN]
   --silent, -s                    suppress the output of dry-run and skip-no-token (default: false)
   --help, -h                      show help (default: false)

$ github-comment help exec
NAME:
   github-comment exec - execute a command and post the result as a comment

USAGE:
   github-comment exec [command options] [arguments...]

OPTIONS:
   --org value                     GitHub organization name
   --repo value                    GitHub repository name
   --token value                   GitHub API token [$GITHUB_TOKEN, $GITHUB_ACCESS_TOKEN]
   --sha1 value                    commit sha1
   --template value                comment template
   --template-key value, -k value  comment template key (default: "default")
   --config value                  configuration file path
   --pr value                      GitHub pull request number (default: 0)
   --var value                     template variable
   --dry-run                       output a comment to standard error output instead of posting to GitHub (default: false)
   --skip-no-token, -n             works like dry-run if the GitHub Access Token isn't set (default: false) [$GITHUB_COMMENT_SKIP_NO_TOKEN]
   --silent, -s                    suppress the output of dry-run and skip-no-token (default: false)
   --help, -h                      show help (default: false)

Configuration

post: variables which can be used in template

• Org
• Repo
• PRNumber
• SHA1
• TemplateKey
• Vars
• Env: the function to get the environment variable https://golang.org/pkg/os/#Getenv
• AvoidHTMLEscape: the function to post a comment without HTML escape by Go's html/template
• Sprig Function: http://masterminds.github.io/sprig/

exec

The configuration of exec is little more difficult than post, but the template key and template is same as post. The each template is list which element has the attribute when and template, and dont_comment. The attribute when is evaluated by the evaluation engine https://github.com/antonmedv/expr , and the result should be boolean. About expr, please see https://github.com/antonmedv/expr/blob/master/docs/Language-Definition.md too. When the evaluation result is false the element is ignored, and the first matching element is used. If dont_comment is true, the comment isn't created. If no element matches, the comment isn't created without error.

In addition to the variables of post command, the following variables can be used in when and template

• Stdout: the command standard output
• Stderr: the command standard error output
• CombinedOutput: Stdout + Stderr
• Command: https://golang.org/pkg/os/exec/#Cmd.String
• JoinCommand: the string which the command and arguments are joined with the space character
• ExitCode: the command exit code

Define reusable template components

templates:
  <template name>: <template content>
post:
  default:
    template: |
      {{template "<template name>" .}} ...

Define variables

vars:
  <variable name>: <variable value>
post:
  default:
    template: |
      {{.Vars.<variable name>}} ...

The variable can be passed with the option -var <variable name>:<variable value> too.

ex.

$ github-comment post -var name:foo

post command supports standard input to pass a template

Instead of -template, we can pass a template from a standard input.

$ echo hello | github-comment post

post a substitute comment when it is failed to post a too long comment

When the comment is too long, it is failed to post a comment due to GitHub API's validation.

{
  "message": "Validation Failed",
  "errors": [
    {
      "resource": "IssueComment",
      "code": "unprocessable",
      "field": "data",
      "message": "Body is too long (maximum is 65536 characters)"
    }
  ],
  "documentation_url": "https://docs.github.com/rest/reference/issues#create-an-issue-comment"
}

If a comment includes the long command standard output, you may encounter the error.

github-comment supports to post a substitute comment in that case.

When it is failed to post a comment of template, github-comment posts a comment of template_for_too_long instead of template.

ex.

post:
  hello:
    template: too long comment
    template_for_too_long: comment is too long
exec:
  hello:
    - when: ExitCode != 0
      template: |
        exit code: {{.ExitCode}}
        combined output: {{.CombinedOutput}}
      template_for_too_long: |
        comment is too long so the command output is omitted
        exit code: {{.ExitCode}}

skip-no-token

https://github.com/suzuki-shunsuke/github-comment/issues/115

In some situation, the GitHub Access Token isn't exposed to the environment variable for the security.

For example, on Drone Secrets are not exposed to pull requests by default.

https://docs.drone.io/secret/repository/

Secrets are not exposed to pull requests by default. This prevents a bad actor from sending a pull request and attempting to expose your secrets.

github-comment requires the GitHub Access Token, so it fails to run github-comment post and github-comment exec.

We can avoid the error by the command line option --skip-no-token or the configuration skip_no_token: true. If the GitHub Access Token is set, this option is ignored. If the GitHub Access Token isn't set, this option works like --dry-run.

Skip to send a comment with Environment variable

https://github.com/suzuki-shunsuke/github-comment/issues/143

When we try to run shell scripts for CI on local for testing, in many case we don't want to send a comment. So github-comment supports to skip to send a comment with an environment variable.

Set the environment variable GITHUB_COMMENT_SKIP to true.

$ export GITHUB_COMMENT_SKIP=true
$ github-comment post -template test # Do nothing
$ github-comment exec -- echo hello # a command is run but a comment isn't sent
hello

Complement options with Platform's built-in Environment variables

The following platforms are supported.

• CircleCI
• GitHub Actions
• Drone
• AWS CodeBuild

To complement, suzuki-shunske/go-ci-env is used.

Builtin Templates

Some default templates are provided. They are overwritten if the same name templates are defined in the configuration file.

• templates.status
• templates.join_command
• templates.hidden_combined_output
• templates.link
• exec.default

templates.status

:{{if eq .ExitCode 0}}white_check_mark{{else}}x{{end}}:

templates.join_command

<pre><code>$ {{.JoinCommand | AvoidHTMLEscape}}</pre></code>

templates.hidden_combined_output

<details><pre><code>{{.CombinedOutput | AvoidHTMLEscape}}</code></pre></details>

templates.link

link is different per CI service.

CircleCI

[workflow](https://circleci.com/workflow-run/{{env "CIRCLE_WORKFLOW_ID" }}) [job]({{env "CIRCLE_BUILD_URL"}}) (job: {{env "CIRCLE_JOB"}})

CodeBuild

[Build link]({{env "CODEBUILD_BUILD_URL"}})

Drone

[build]({{env "DRONE_BUILD_LINK"}}) [step]({{env "DRONE_BUILD_LINK"}}/{{env "DRONE_STAGE_NUMBER"}}/{{env "DRONE_STEP_NUMBER"}})

GitHub Actions

[Build link](https://github.com/{{env "GITHUB_REPOSITORY"}}/actions/runs/{{env "GITHUB_RUN_ID"}})

exec.default

when: ExitCode != 0
template: |
  {{template "status" .}} {{template "link" .}}

  {{template "join_command" .}}

  {{template "hidden_combined_output" .}}`

Configuration file path

The configuration file path can be specified with the --config (-c) option. If the confgiuration file path isn't specified, the file named .github-comment.yml or .github-comment.yaml would be searched from the current directory to the root directory.

Blog

Written in Japanese. https://techblog.szksh.cloud/github-comment/

License

MIT