Code Quality

Moved to GitLab Free in 13.2.

Use Code Quality to analyze your source code’s quality and complexity. This helps keep your project’s code simple, readable, and easier to maintain. Code Quality should supplement your other review processes, not replace them.

Code Quality uses the open source Code Climate tool, and selected plugins, to analyze your source code. To confirm if your code’s languages are covered, see the Code Climate list of Supported Languages for Maintainability. You can extend the code coverage either by using Code Climate Analysis Plugins or a custom tool.

Run Code Quality reports in your CI/CD pipeline to verify changes don’t degrade your code’s quality, before committing them to the default branch.

Features per tier

Different features are available in different GitLab tiers, as shown in the following table:

CapabilityIn FreeIn PremiumIn Ultimate
Configure scanners
Integrate custom scanners
See findings in merge request widget
Generate JSON or HTML report artifacts
See reports in CI pipelines
See findings in merge request diff view

View Code Quality results

Code Quality results are shown in the:

  • Merge request widget
  • Merge request changes view
  • Pipeline details view

Merge request widget

Moved to GitLab Free in 13.2.

Code Quality analysis results display in the merge request widget area if a report from the target branch is available for comparison.

Code Quality Widget

Merge request changes view

Version history

Code Quality results display in the merge request Changes view. Lines containing Code Quality issues are marked by an indicator beside the gutter. Hover over the marker for details of the issue.

Code Quality MR diff report

Pipeline details view

The full list of Code Quality violations generated by a pipeline is shown in the Code Quality tab of the pipeline’s details page.

Code Quality Report

Enable Code Quality

Prerequisites:

  • GitLab CI/CD configuration (.gitlab-ci.yml) must include the test stage.
  • If you’re using shared runners, the Code Quality job must be configured for the Docker-in-Docker workflow.
  • If you’re using private runners, you should use an alternative configuration recommended for running Code Quality analysis more efficiently.
  • The runner must have enough disk space to store the generated Code Quality files. For example, on the GitLab project the files are approximately 7 GB.

To enable Code Quality, either:

  • Enable Auto DevOps, which includes Auto Code Quality.

  • Include the Code Quality template in your .gitlab-ci.yml file.

    Example:

       include:
       - template: Code-Quality.gitlab-ci.yml
    

    Code Quality now runs in pipelines.

caution
On self-managed instances, if a malicious actor compromises the Code Quality job definition they could execute privileged Docker commands on the runner host. Having proper access control policies mitigates this attack vector by allowing access only to trusted actors.

Improve Code Quality performance with private runners

If you have private runners, you should use this configuration for improved performance of Code Quality because:

  • Privileged mode is not used.
  • Docker-in-Docker is not used.
  • Docker images, including all CodeClimate images, are cached, and not re-fetched for subsequent jobs.

This alternative configuration uses socket binding to share the Runner’s Docker daemon with the job environment. Before implementing this configuration, consider its limitations.

To use private runners:

  1. Register a new runner:

    $ gitlab-runner register --executor "docker" \
      --docker-image="docker:stable" \
      --url "https://gitlab.com/" \
      --description "cq-sans-dind" \
      --tag-list "cq-sans-dind" \
      --locked="false" \
      --access-level="not_protected" \
      --docker-volumes "/cache"\
      --docker-volumes "/builds:/builds"\
      --docker-volumes "/var/run/docker.sock:/var/run/docker.sock" \
      --registration-token="<project_token>" \
      --non-interactive
    
  2. Optional, but recommended: Set the builds directory to /tmp/builds, so job artifacts are periodically purged from the runner host. If you skip this step, you must clean up the default builds directory (/builds) yourself. You can do this by adding the following two flags to gitlab-runner register in the previous step.

    --builds-dir "/tmp/builds"
    --docker-volumes "/tmp/builds:/tmp/builds" # Use this instead of --docker-volumes "/builds:/builds"
    

    The resulting configuration:

    [[runners]]
      name = "cq-sans-dind"
      url = "https://gitlab.com/"
      token = "<project_token>"
      executor = "docker"
      builds_dir = "/tmp/builds"
      [runners.docker]
        tls_verify = false
        image = "docker:stable"
        privileged = false
        disable_entrypoint_overwrite = false
        oom_kill_disable = false
        disable_cache = false
        volumes = ["/cache", "/var/run/docker.sock:/var/run/docker.sock", "/tmp/builds:/tmp/builds"]
        shm_size = 0
      [runners.cache]
        [runners.cache.s3]
        [runners.cache.gcs]
    
  3. Apply two overrides to the code_quality job created by the template:

    include:
      - template: Code-Quality.gitlab-ci.yml
    
    code_quality:
      services:            # Shut off Docker-in-Docker
      tags:
        - cq-sans-dind     # Set this job to only run on our new specialized runner
    

Code Quality now runs in standard Docker mode.

Disable Code Quality

The code_quality job doesn’t run if the $CODE_QUALITY_DISABLED CI/CD variable is present. Refer to the CI/CD variables documentation to learn more about how to define one.

To disable Code Quality, create a custom CI/CD variable named CODE_QUALITY_DISABLED, for either:

Customizing scan settings

The Code Quality scan settings can be changed using CI/CD variables in .gitlab-ci.yml.

To configure the Code Quality job:

  1. Declare a job with the same name as the Code Quality job, after the template’s inclusion.
  2. Specify additional keys in the job’s stanza.

For an example, see Download output in JSON format.

Available CI/CD variables

In GitLab 13.4 and later, the option to override the Code Quality environment variables was added.

Code Quality can be customized by defining available CI/CD variables:

CI/CD variableDescription
SOURCE_CODEPath to the source code to scan.
TIMEOUT_SECONDSCustom timeout for the codeclimate analyze command.
CODECLIMATE_DEBUGSet to enable Code Climate debug mode
CODECLIMATE_DEVSet to enable --dev mode which lets you run engines not known to the CLI.
REPORT_STDOUTSet to print the report to STDOUT instead of generating the usual report file.
REPORT_FORMATSet to control the format of the generated report file. One of: json\|html.
ENGINE_MEMORY_LIMIT_BYTESSet the memory limit for engines, default is 1,024,000,000 bytes.
CODE_QUALITY_DISABLEDPrevents the Code Quality job from running.
CODECLIMATE_PREFIXSet a prefix to use with all docker pull commands in CodeClimate engines. Useful for offline scanning.

Output

Code Quality creates a file named gl-code-quality-report.json. The content of this file is processed internally and the results shown in the UI. To see the raw results, you can configure the Code Quality job to allow download of this file. Format options are JSON format, HTML format, or both. Use the HTML format to view the report in a more human-readable format. For example, you could publish the HTML format file on GitLab Pages for even easier reviewing.

Download output in JSON format

To be able to download the Code Quality report in JSON format, declare the gl-code-quality-report.json file as an artifact of the code_quality job:

include:
  - template: Code-Quality.gitlab-ci.yml

code_quality:
  artifacts:
    paths: [gl-code-quality-report.json]

The full JSON file is available as a downloadable artifact of the code_quality job.

Download output in JSON and HTML format

HTML report format introduced in GitLab 13.6.

note
To create the HTML format file, the Code Quality job must be run twice, once for each format. In this configuration, the JSON format file is created but it is only processed internally.

To be able to download the Code Quality report in both JSON and HTML format, add another job to your template by using extends: code_quality:

include:
  - template: Code-Quality.gitlab-ci.yml

code_quality_html:
  extends: code_quality
  variables:
    REPORT_FORMAT: html
  artifacts:
    paths: [gl-code-quality-report.html]

Both the JSON and HTML files are available as downloadable artifacts of the code_quality job.

Download output in only HTML format

To download the Code Quality report in only an HTML format file, set REPORT_FORMAT to html in the existing job.

note
This does not create a JSON format file, so Code Quality results are not shown in the merge request widget, pipeline report, or changes view.
include:
  - template: Code-Quality.gitlab-ci.yml

code_quality:
  variables:
    REPORT_FORMAT: html
  artifacts:
    paths: [gl-code-quality-report.html]

The HTML file is available as a downloadable artifact of the code_quality job.

Use Code Quality with merge request pipelines

The default Code Quality configuration does not allow the code_quality job to run on merge request pipelines.

To enable Code Quality to run on merge request pipelines, overwrite the code quality rules, or workflow: rules, so that they match your current rules.

For example:

include:
  - template: Code-Quality.gitlab-ci.yml

code_quality:
  rules:
    - if: $CODE_QUALITY_DISABLED
      when: never
    - if: $CI_PIPELINE_SOURCE == "merge_request_event" # Run code quality job in merge request pipelines
    - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH      # Run code quality job in pipelines on the default branch (but not in other branch pipelines)
    - if: $CI_COMMIT_TAG                               # Run code quality job in pipelines for tags

Use a private container image registry

Introduced in GitLab 13.7.

Using a private container image registry can reduce the time taken to download images, and also reduce external dependencies. Because of the nested architecture of container execution, the registry prefix must be specifically configured to be passed down into CodeClimate’s subsequent docker pull commands for individual engines.

The following variables can address all of the required image pulls:

  • CODE_QUALITY_IMAGE: A fully prefixed image name that can be located anywhere accessible from your job environment. GitLab Container Registry can be used here to host your own copy.
  • CODECLIMATE_PREFIX: The domain of your intended container image registry. This is a configuration option supported by CodeClimate CLI. You must:
    • Include a trailing slash (/).
    • Not include a protocol prefix, such as https://.
  • CODECLIMATE_REGISTRY_USERNAME: An optional variable to specify the username for the registry domain parsed from CODECLIMATE_PREFIX.
  • CODECLIMATE_REGISTRY_PASSWORD: An optional variable to specify the password for the registry domain parsed from CODECLIMATE_PREFIX.
include:
  - template: Code-Quality.gitlab-ci.yml

code_quality:
  variables:
    CODE_QUALITY_IMAGE: "my-private-registry.local:12345/codequality:0.85.24"
    CODECLIMATE_PREFIX: "my-private-registry.local:12345/"

This example is specific to GitLab Code Quality. For more general instructions on how to configure DinD with a registry mirror, see Enable registry mirror for Docker-in-Docker service.

Required images

The following images are required for the default .codeclimate.yml:

  • codeclimate/codeclimate-structure:latest
  • codeclimate/codeclimate-csslint:latest
  • codeclimate/codeclimate-coffeelint:latest
  • codeclimate/codeclimate-duplication:latest
  • codeclimate/codeclimate-eslint:latest
  • codeclimate/codeclimate-fixme:latest
  • codeclimate/codeclimate-rubocop:rubocop-0-92

If you are using a custom .codeclimate.yml configuration file, you must add the specified plugins in your private container registry.

Use DockerHub with authentication

You can use DockerHub as an alternate source of the Code Quality images.

Prerequisites:

To use DockerHub, configure the following variables in the .gitlab-ci.yml file:

  • CODECLIMATE_PREFIX
  • CODECLIMATE_REGISTRY_USERNAME
  • CODECLIMATE_REGISTRY_PASSWORD

Example:

include:
  - template: Jobs/Code-Quality.gitlab-ci.yml

code_quality:
  variables:
    CODECLIMATE_PREFIX: "registry-1.docker.io/"
    CODECLIMATE_REGISTRY_USERNAME: $DOCKERHUB_USERNAME
    CODECLIMATE_REGISTRY_PASSWORD: $DOCKERHUB_PASSWORD

Use the Dependency Proxy

You can use a Dependency Proxy to reduce the time taken to download dependencies.

Prerequisite:

To reference the Dependency Proxy, configure the following variables in the .gitlab-ci.yml file:

  • CODE_QUALITY_IMAGE
  • CODECLIMATE_PREFIX
  • CODECLIMATE_REGISTRY_USERNAME
  • CODECLIMATE_REGISTRY_PASSWORD

For example:

include:
  - template: Code-Quality.gitlab-ci.yml

code_quality:
  variables:
    CODE_QUALITY_IMAGE: "$CI_DEPENDENCY_PROXY_GROUP_IMAGE_PREFIX/codequality:0.85.24"
    ## You must add a trailing slash to `$CI_DEPENDENCY_PROXY_GROUP_IMAGE_PREFIX`.
    CODECLIMATE_PREFIX: $CI_DEPENDENCY_PROXY_GROUP_IMAGE_PREFIX/
    CODECLIMATE_REGISTRY_USERNAME: $CI_DEPENDENCY_PROXY_USER
    CODECLIMATE_REGISTRY_PASSWORD: $CI_DEPENDENCY_PROXY_PASSWORD

Implement a custom tool

You can integrate a custom tool into GitLab to provide Code Quality reports.

The Code Quality report artifact JSON file must contain an array of objects with the following properties:

NameDescription
descriptionA description of the code quality violation.
fingerprintA unique fingerprint to identify the code quality violation. For example, an MD5 hash.
severityA severity string (can be info, minor, major, critical, or blocker).
location.pathThe relative path to the file containing the code quality violation.
location.lines.begin or location.positions.begin.line The line on which the code quality violation occurred.
note
Although the Code Climate specification supports more properties, those are ignored by GitLab. The GitLab parser does not allow a byte order mark at the beginning of the file.

To implement a custom Code Quality tool:

  1. Define a job in your .gitlab-ci.yml file that generates the Code Quality report artifact.
  2. Configure the tool to generate the Code Quality report artifact as a JSON file that implements a subset of the Code Climate spec.

Example:

[
  {
    "description": "'unused' is assigned a value but never used.",
    "fingerprint": "7815696ecbf1c96e6894b779456d330e",
    "severity": "minor",
    "location": {
      "path": "lib/index.js",
      "lines": {
        "begin": 42
      }
    }
  }
]

Using Analysis Plugins

Code Quality functionality can be extended by using Code Climate Analysis Plugins.

For example, to use the SonarJava analyzer:

  1. Add a file named .codeclimate.yml to the root of your repository
  2. Add to the .codeclimate.yml the enablement code for the plugin to the root of your repository:
  version: "2"
  plugins:
    sonar-java:
      enabled: true

This adds SonarJava to the plugins: section of the default .codeclimate.yml included in your project.

Changes to the plugins: section do not affect the exclude_patterns section of the default .codeclimate.yml. See the Code Climate documentation on excluding files and folders for more details.

Troubleshooting

Changing the default configuration has no effect

A common issue is that the terms Code Quality (GitLab specific) and Code Climate (Engine used by GitLab) are very similar. You must add a .codeclimate.yml file to change the default configuration, not a .codequality.yml file. If you use the wrong filename, the default .codeclimate.yml is still used.

No Code Quality report is displayed in a merge request

This can be due to multiple reasons:

  • You just added the Code Quality job in your .gitlab-ci.yml. The report does not have anything to compare to yet, so no information can be displayed. It only displays after future merge requests have something to compare to.
  • Your pipeline is not set to run the code quality job on your target branch. If there is no report generated from the target branch, your merge request branch reports have nothing to compare to. In this situation you get an error stating Base pipeline codequality artifact not found.
  • The artifacts:expire_in CI/CD setting can cause the Code Quality artifacts to expire faster than desired.
  • The widgets use the pipeline of the latest commit to the target branch. If commits are made to the default branch that do not run the code quality job, this may cause the merge request widget to have no base report for comparison.
  • If you use the REPORT_STDOUT environment variable, no report file is generated and nothing displays in the merge request.

Only a single Code Quality report is displayed, but more are defined

Starting in GitLab 15.7, Code Quality combines the results from all jobs in a pipeline.

In previous versions, GitLab only uses the Code Quality artifact from the latest created job (with the largest job ID). If multiple jobs in a pipeline generate a code quality artifact, those of earlier jobs are ignored.

To avoid confusion, configure only one job to generate a gl-code-quality-report.json file.

RuboCop errors

When using Code Quality jobs on a Ruby project, you can encounter problems running RuboCop. For example, the following error can appear when using either a very recent or very old version of Ruby:

/usr/local/bundle/gems/rubocop-0.52.1/lib/rubocop/config.rb:510:in `check_target_ruby':
Unknown Ruby version 2.7 found in `.ruby-version`. (RuboCop::ValidationError)
Supported versions: 2.1, 2.2, 2.3, 2.4, 2.5

This is caused by the default version of RuboCop used by the check engine not covering support for the Ruby version in use.

To use a custom version of RuboCop that supports the version of Ruby used by the project, you can override the configuration through a .codeclimate.yml file created in the project repository.

For example, to specify using RuboCop release 0.67:

version: "2"
plugins:
  rubocop:
    enabled: true
    channel: rubocop-0-67

No Code Quality appears on merge requests when using custom tool

If your merge requests do not show any Code Quality changes when using a custom tool, ensure that the line property is an integer.

Error: Could not analyze code quality

You might get the error:

error: (CC::CLI::Analyze::EngineFailure) engine pmd ran for 900 seconds and was killed
Could not analyze code quality for the repository at /code

If you enabled any of the Code Climate plugins, and the Code Quality CI/CD job fails with this error message, it’s likely the job takes longer than the default timeout of 900 seconds:

To work around this problem, set TIMEOUT_SECONDS to a higher value in your .gitlab.-ci.yml file.

For example:

variables:
  TIMEOUT_SECONDS: 3600

Using Code Quality with Kubernetes CI executor

Code Quality requires a Docker in Docker setup to work. The Kubernetes executor already has support for this.

To ensure Code Quality jobs can run on a Kubernetes executor:

Error: x509: certificate signed by unknown authority

If you set the CODE_QUALITY_IMAGE to an image that is hosted in a Docker registry which uses a TLS certificate that is not trusted, such as a self-signed certificate, you can see errors like the one below:

$ docker pull --quiet "$CODE_QUALITY_IMAGE"
Error response from daemon: Get https://gitlab.example.com/v2/: x509: certificate signed by unknown authority

To fix this, configure the Docker daemon to trust certificates by putting the certificate inside of the /etc/docker/certs.d directory.

This Docker daemon is exposed to the subsequent Code Quality Docker container in the GitLab Code Quality template and should be to exposed any other containers in which you want to have your certificate configuration apply.

Docker

If you have access to GitLab Runner configuration, add the directory as a volume mount.

Replace gitlab.example.com with the actual domain of the registry.

Example:

[[runners]]
  ...
  executor = "docker"
  [runners.docker]
    ...
    privileged = true
    volumes = ["/cache", "/etc/gitlab-runner/certs/gitlab.example.com.crt:/etc/docker/certs.d/gitlab.example.com/ca.crt:ro"]

Kubernetes

If you have access to GitLab Runner configuration and the Kubernetes cluster, you can mount a ConfigMap.

Replace gitlab.example.com with the actual domain of the registry.

  1. Create a ConfigMap with the certificate:

    kubectl create configmap registry-crt --namespace gitlab-runner --from-file /etc/gitlab-runner/certs/gitlab.example.com.crt
    
  2. Update GitLab Runner config.toml to specify the ConfigMap:

    [[runners]]
      ...
      executor = "kubernetes"
      [runners.kubernetes]
        image = "alpine:3.12"
        privileged = true
        [[runners.kubernetes.volumes.config_map]]
          name = "registry-crt"
          mount_path = "/etc/docker/certs.d/gitlab.example.com/ca.crt"
          sub_path = "gitlab.example.com.crt"