:dog: A code review dog who keeps your codebase healthy

reviewdog - A code review dog who keeps your codebase healthy

Gitter LICENSE Go Report Card GoDoc releases

reviewdog logo

CI Status
Travis CI Travis Build Status
CircleCI CircleCI Build Status
codecov codecov

“reviewdog” provides a way to post review comments to code hosting service, such as GitHub, automatically by integrating with any linter tools with ease. It uses any output of lint tools and post them as a comment if the file and line are in diff of patches to review.

reviewdog also supports run in local environment to filter output of lint tools by diff.

design doc

Automatic code review (sample PR)


Local run



Get the binary release (recommended way)


go get -u



reviewdog accepts any compiler or linter result from stdin and parses it with scan-f like ‘errorformat’, which is the port of Vim’s errorformat feature.

For example, if the result format is {file}:{line number}:{column number}: {message}, errorformat should be %f:%l:%c: %m and you can pass it as -efm arguments.

$ golint ./...
comment_iowriter.go:11:6: exported type CommentWriter should have comment or be unexported
$ golint ./... | reviewdog -efm="%f:%l:%c: %m" -diff="git diff master"
name description
%f file name
%l line number
%c column number
%m error message
%% the single ‘%’ character

Please see haya14busa/errorformat and :h errorformat if you want to deal with more complex output. ‘errorformat’ can handle more complex output like multi-line error message.

By this ‘errorformat’ feature, reviewdog can support any tools output with ease.

Available pre-defined ‘errorformat’

But, you don’t have to write ‘errorformat’ in many cases. reviewdog supports pre-defined errorformat for major compiler or linter tools.

You can find available errorformat name by reviewdog -list and you can use it with -f={name}.

$ reviewdog -list
golint          linter for Go source code                                       -
govet           Vet examines Go source code and reports suspicious problems     -
sbt             the interactive build tool                                      -
$ golint ./... | reviewdog -f=golint -diff="git diff master"

You can add supported pre-defined ‘errorformat’ by contributing to haya14busa/errorformat

checkstyle format

reviewdog also accepts checkstyle XML format as well. If the linter supports checkstyle format as a report format, you can us -f=checkstyle instead of using ‘errorformat’.

# Local
$ eslint -f checkstyle . | reviewdog -f=checkstyle -diff="git diff"

# CI (overwrite tool name which is shown in review comment by -name arg)
$ eslint -f checkstyle . | reviewdog -f=checkstyle -name="eslint" -ci="circle-ci"

Also, if you want to pass other Json/XML/etc… format to reviewdog, you can write a converter.

$ <linter> | <convert-to-checkstyle> | reviewdog -f=checkstyle -name="<linter>" -ci="circle-ci"

Project Configuration Based Run


reviewdog can also be controlled via the reviewdog.yml configuration file instead of “-f” or “-efm” arguments.

With reviewdog.yml, you can run the same commands both CI service and local environment including editor intergration with ease.


    cmd: <command> # (required)
    errorformat: # (optional if there is supporeted format for <tool-name>. see reviewdog -list)
      - <list of errorformat>
    name: <tool-name> # (optional. you can overwrite <tool-name> defined by runner key)

  # examples
    cmd: golint ./...
      - "%f:%l:%c: %m"
    cmd: go tool vet -all -shadowstrict .
$ reviewdog -diff="git diff master"
project/run_test.go:61:28: [golint] error strings should not end with punctuation
project/run.go:57:18: [errcheck]        defer os.Setenv(name, os.Getenv(name))
project/run.go:58:12: [errcheck]        os.Setenv(name, "")
# You can use -conf to specify config file path.
$ reviewdog -ci=droneio -conf=./reviewdog.yml

Output format for project config based run is one of following formats.

  • <file>: [<tool name>] <message>
  • <file>:<lnum>: [<tool name>] <message>
  • <file>:<lnum>:<col>: [<tool name>] <message>

Run locally

reviewdog can find new introduced warnings or error by filtering linter results using diff. You can pass diff comamnd as -diff arg, like -diff="git diff", -diff="git diff master", etc… when you use reviewdog in local environment.

Working with GitHub and CI services

reviewdog can intergrate with CI service and post review comments to report results automatically as well!

Supported code hosting (or code review) service

At the time of writing, reviewdog supports GitHub and GitHub Enterprise as a code hosting service for posting comments.

It may support Gerrit, Bitbucket, or other services later.

reviewdog requires GitHub Personal API Access token as an environment variable (REVIEWDOG_GITHUB_API_TOKEN) to post comments to GitHub or GitHub Enterprise. Go to and generate new API token. Check repo for private repositories or public_repo for public repositories. Export the token environment variable by secure way, depending on CI services.

For GitHub Enterprise, please set API endpoint by environment variable.

export GITHUB_API=""

Supported CI services

Name Pull Request from the same repository Pull Request from forked repository
Travis CI :o: :x:
CircleCI :o: :x: (but possible with insecure way) (OSS) v0.4 :o: :o:
common (Your managed CI server like Jenkins) :o: :o:

reviewdog can run in CI services which supports Pull Request build and secret environment variable feature for security reason.

But, for the Pull Request from forked repository, most CI services restrict secret environment variable for security reason, to avoid leak of secret data with malicious Pull Request. (Travis CI, CircleCI)

Travis CI

Store GitHub API token by travis encryption keys.

$ gem install travis
$ travis encrypt REVIEWDOG_GITHUB_API_TOKEN=<your token> --add


    - secure: xxxxxxxxxxxxx

  - mkdir -p ~/bin/ && export export PATH="~/bin/:$PATH"
  - curl -fSL$REVIEWDOG_VERSION/reviewdog_linux_amd64 -o ~/bin/reviewdog && chmod +x ~/bin/reviewdog

  - >-
    golint ./... | reviewdog -f=golint -ci=travis

Examples -

Circle CI

Store GitHub API token in Environment variables - CircleCI

Circle CI do not build by pull-request hook by default, so please turn on “Only build pull requests” in Advanced option in Circle CI (changelog).

Pull Requests from fork repo cannot set environment variable for security reason. However, if you want to run fork PR builds for private repositories or want to run reviewdog for forked PR to OSS project, CircleCI have an option to enable it. Unsafe fork PR builds

I thinks it’s not a big problem if GitHub API token has limited scope (e.g. only public_repo), but if you enables Unsafe fork PR builds to run reviewdog for fork PR, please use it at your own risk.

circle.yml sample


    - curl -fSL$REVIEWDOG_VERSION/reviewdog_linux_amd64 -o reviewdog && chmod +x ./reviewdog

    - >-
      go tool vet -all -shadowstrict . 2>&1 | ./reviewdog -f=govet -ci="circle-ci"

Store GitHub API token in environment variable. Secrets · Drone

Install ‘drone’ cli command and setup configuration.

echo '.drone.sec.yaml' >> .gitignore



.drone.yaml example

    image: golang
      - go get
      - |
        go tool vet -all -shadowstrict . 2>&1 | reviewdog -f=govet -ci=droneio
      event: pull_request

Finally, run drone secure to encrypt the .drone.sec.yaml file and generate a .drone.sec file

$ drone secure --repo {github-user-name}/{repo-name} --in .drone.sec.yaml supports encrypted environment variable for fork Pull Request build in secure way, but you have to read document carefully not to expose secret data unexpectedly.

Common (Jenkins, local, etc…)

You can use reviewdog to post review comments anywhere with following environment variables.

name description
CI_PULL_REQUEST Pull Request number (e.g. 14)
CI_COMMIT SHA1 for the current build
CI_REPO_OWNER repository owner (e.g. “haya14busa” for
CI_REPO_NAME repository name (e.g. “reviewdog” for
$ export CI_PULL_REQUEST=14
$ export CI_REPO_OWNER=haya14busa
$ export CI_REPO_NAME=reviewdog
$ export CI_COMMIT=$(git rev-parse HEAD)
$ export REVIEWDOG_GITHUB_API_TOKEN="<your token>"
$ golint ./... | reviewdog -f=golint -ci=common

:bird: Author

haya14busa (

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