Using custom queries with the CodeQL CLI

You can write your own CodeQL queries to find specific vulnerabilities and errors.

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About custom queries and the CodeQL CLI

You can customize your CodeQL analyses by writing your own queries to highlight specific vulnerabilities or errors.

This topic is specifically about writing queries to use with the database analyze command to produce interpreted results.

Nota:

Las consultas que se ejecutan con database analyze tienen estrictos requisitos de metadatos. También puedes ejecutar consultas con los siguientes subcomandos de nivel de asociación:

  • database run-queries, que genera resultados no interpretados en un formato binario intermedio denominado BQRS.
  • query run, que genera archivos BQRS o imprime tablas de resultados directamente en la línea de comandos. La visualización de los resultados directamente en la línea de comandos puede ser útil para el desarrollo de consultas iterativas mediante la CLI.

Las consultas que se ejecutan con estos comandos no tienen los mismos requisitos de metadatos. Aun así, para guardar datos legibles para el usuario, debes procesar cada archivo de resultados BQRS mediante el subcomando de asociación bqrs decode. Por lo tanto, en la mayoría de los casos de uso, es más fácil usar el comando database analyze para generar directamente resultados interpretados.

Writing a valid query

Before running a custom analysis you need to write a valid query, and save it in a file with a .ql extension. There is extensive documentation available to help you write queries. For more information, see CodeQL queries.

Including query metadata

Query metadata is included at the top of each query file. It provides users with information about the query, and tells the CodeQL CLI how to process the query results.

When running queries with the database analyze command, you must include the following two properties to ensure that the results are interpreted correctly:

  • Query identifier (@id): a sequence of words composed of lowercase letters or digits, delimited by / or -, identifying and classifying the query.

  • Query type (@kind): identifies the query as a simple alert (@kind problem), an alert documented by a sequence of code locations (@kind path-problem), for extractor troubleshooting (@kind diagnostic), or a summary metric (@kind metric and @tags summary).

For more information about these metadata properties, see Metadata for CodeQL queries and the Query metadata style guide.

Nota:

Metadata requirements may differ if you want to use your query with other applications. For more information, see Metadata for CodeQL queries.

Packaging custom QL queries

When you write your own queries with the intention to share them with others, you should save them in a custom CodeQL pack. You can publish the pack as a CodeQL pack to GitHub Packages - the GitHub Container registry. For more information, see Customizing analysis with CodeQL packs.

CodeQL packs organize the files used in CodeQL analysis and can store queries, library files, query suites, and important metadata. Their root directory must contain a file named qlpack.yml. Your custom queries should be saved in the CodeQL pack root, or its subdirectories.

For each CodeQL pack, the qlpack.yml file includes information that tells the CodeQL CLI how to compile the queries, which other CodeQL packs and libraries the pack depends on, and where to find query suite definitions. For more information about what to include in this file, see Customizing analysis with CodeQL packs.

Including query help for custom CodeQL queries in SARIF files

If you use the CodeQL CLI to run code scanning analyses on third party CI/CD systems, you can include the query help for your custom queries in SARIF files generated during an analysis. After uploading the SARIF file to GitHub, the query help is shown in the code scanning UI for any alerts generated by the custom queries.

From CodeQL CLI v2.7.1 onwards, you can include markdown-rendered query help in SARIF files by providing the --sarif-add-query-help option when running codeql database analyze.

You can write query help for custom queries directly in a markdown file and save it alongside the corresponding query. Alternatively, for consistency with the standard CodeQL queries, you can write query help in the .qhelp format. Query help written in .qhelp files can’t be included in SARIF files, and they can’t be processed by code scanning so must be converted to markdown before running the analysis. For more information, see Query help files and Testing query help files.

Contributing to the CodeQL repository

If you would like to share your query with other CodeQL users, you can open a pull request in the CodeQL repository. For more information, see Contributing to CodeQL.

Further reading