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

#1 (comment)

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 #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

#1 (comment)

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

#1 (comment)

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]
   --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]
   --help, -h                      show help (default: false)

Configuration

post: variables which can be used in template

Org
Repo
PRNumber
SHA1
TemplateKey
Vars

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
Env: the function to get the environment variable https://golang.org/pkg/os/#Getenv

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

#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.

Complement options with Platform's built-in Environment variables

The following platforms are supported.

CircleCI
GitHub Actions
Drone

CircleCI

https://circleci.com/docs/2.0/env-vars/#built-in-environment-variables

org: CIRCLE_PROJECT_USERNAME
repo: CIRCLE_PROJECT_REPONAME
pr: CIRCLE_PULL_REQUEST
revision: CIRCLE_SHA

Drone

https://docs.drone.io/pipeline/environment/reference/

org: DRONE_REPO_OWNER
repo: DRONE_REPO_NAME
pr: DRONE_PULL_REQUEST
revision: DRONE_COMMIT_SHA1

GitHub Actions

https://docs.github.com/en/actions/configuring-and-managing-workflows/using-environment-variables#default-environment-variables

org: GITHUB_REPOSITORY
repo: GITHUB_REPOSITORY
pr: GITHUB_EVENT_PATH
revision: GITHUB_SHA

AWS CodeBuild

https://docs.aws.amazon.com/codebuild/latest/userguide/build-env-ref-env-vars.html

org: CODEBUILD_SOURCE_REPO_URL
repo: CODEBUILD_SOURCE_REPO_URL
pr: CODEBUILD_SOURCE_VERSION
revision: CODEBUILD_RESOLVED_SOURCE_VERSION

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

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

README.md

README.md

github-comment

Note

Install

Getting Started

post

exec

Usage

Configuration

post: variables which can be used in template

exec

Define reusable template components

Define variables

post command supports standard input to pass a template

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

skip-no-token

Complement options with Platform's built-in Environment variables

CircleCI

Drone

GitHub Actions

AWS CodeBuild

Configuration file path

Blog

License

Files

README.md

Latest commit

History

README.md

File metadata and controls

github-comment

Note

Install

Getting Started

post

exec

Usage

Configuration

post: variables which can be used in template

exec

Define reusable template components

Define variables

post command supports standard input to pass a template

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

skip-no-token

Complement options with Platform's built-in Environment variables

CircleCI

Drone

GitHub Actions

AWS CodeBuild

Configuration file path

Blog

License