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Dagster GraphQL API

note

The GraphQL API is still evolving and is subject to breaking changes. A large portion of the API is primarily for internal use by the Dagster webserver. For any of the queries below, we will be clear about breaking changes in release notes.

Dagster exposes a GraphQL API that allows clients to interact with Dagster programmatically. The API allows users to:

  • Query information about Dagster runs, both historical and currently executing
  • Retrieve metadata about repositories, jobs, and ops, such as dependency structure and config schemas
  • Launch job executions and re-executions, allowing users to trigger executions on custom events

Using the GraphQL API​

The GraphQL API is served from thewebserver. To start the server, run the following:

dagster dev

The webserver serves the GraphQL endpoint at the /graphql endpoint. If you are running the webserver locally on port 3000, you can access the API at http://localhost:3000/graphql.

Using the GraphQL playground​

You can access the GraphQL Playground by navigating to the /graphql route in your browser. The GraphQL playground contains the full GraphQL schema and an interactive playground to write and test queries and mutations:

GraphQL playground

Exploring the GraphQL schema and documentation​

Clicking on the Docs tab on the right edge of the playground opens up interactive documentation for the GraphQL API. The interactive documentation is the best way to explore the API and get information about which fields are available on the queries and mutations:

GraphQL docs

Python client​

Dagster also provides a Python client to interface with Dagster's GraphQL API from Python. For more information, see "Dagster Python GraphQL client".

Example queries​

Get a list of Dagster runs​

You may eventually accumulate too many runs to return in one query. The runsOrError query takes in optional cursor and limit arguments for pagination:

query PaginatedRunsQuery($cursor: String) {
  runsOrError(
    cursor: $cursor
    limit: 10
  ) {
    __typename
    ... on Runs {
      results {
        runId
        jobName
        status
        runConfigYaml
        startTime
        endTime
      }
    }
  }
}

Get a list of repositories​

This query returns the names and location names of all the repositories currently loaded:

query RepositoriesQuery {
  repositoriesOrError {
    ... on RepositoryConnection {
      nodes {
        name
        location {
          name
        }
      }
    }
  }
}

Get a list of jobs within a repository​

Given a repository, this query returns the names of all the jobs in the repository.

This query takes a selector, which is of type RepositorySelector. A repository selector consists of both the repository location name and repository name.

query JobsQuery(
  $repositoryLocationName: String!
  $repositoryName: String!
) {
  repositoryOrError(
    repositorySelector: {
      repositoryLocationName: $repositoryLocationName
      repositoryName: $repositoryName
    }
  ) {
    ... on Repository {
      jobs {
        name
      }
    }
  }
}

Launch a run​

To launch a run, use the launchRun mutation. Here, we define LaunchRunMutation to wrap our mutation and pass in the required arguments as query variables. For this query, the required arguments are:

  • selector - A dictionary that contains the repository location name, repository name, and job name.
  • runConfigData - The run config for the job execution. Note: Note that runConfigData is of type RunConfigData. This type is used when passing in an arbitrary object for run config. This is any-typed in the GraphQL type system, but must conform to the constraints of the config schema for this job. If it doesn't, the mutation returns a RunConfigValidationInvalid response.
mutation LaunchRunMutation(
  $repositoryLocationName: String!
  $repositoryName: String!
  $jobName: String!
  $runConfigData: RunConfigData!
) {
  launchRun(
    executionParams: {
      selector: {
        repositoryLocationName: $repositoryLocationName
        repositoryName: $repositoryName
        jobName: $jobName
      }
      runConfigData: $runConfigData
    }
  ) {
    __typename
    ... on LaunchRunSuccess {
      run {
        runId
      }
    }
    ... on RunConfigValidationInvalid {
      errors {
        message
        reason
      }
    }
    ... on PythonError {
      message
    }
  }
}

Terminate an in-progress run​

If you want to stop execution of an in-progress run, use the terminateRun mutation. The only required argument for this mutation is the ID of the run.

mutation TerminateRun($runId: String!) {
  terminateRun(runId: $runId){
    __typename
    ... on TerminateRunSuccess{
      run {
        runId
      }
    }
    ... on TerminateRunFailure {
      message
    }
    ... on RunNotFoundError {
      runId
    }
    ... on PythonError {
      message
      stack
    }
  }
}