graphile-worker-helpers v1.1.2

Graphile worker helpers

A set of helpers adding hierarchy and job progress functionnality to the graphile-worker package inspired by BullMQ's Flow as well as saving intermediary results for improved job recovery and progress management.

Installation

All tables will be created in the graphile_worker_helpers and assume that graphile-worker was installed in the graphile_worker schema.

Performance hit

When many jobs with the same parent finish around the same time, they may take time to complete.

Handling child job failure

Similar to BullMQ, you can chose what happens when a child job fails permanently:

• fail-parent (default): fail the parent when a child fails. Can be recursive if the parent has the same option.
• ignore: the error is ignored and the job is marked as completed. The parent can still access the intermediate result.
• remove: the job and its relation to the parent are removed. The intermediate result is lost if there was any.

Functions

Here is an exhaustive list of the functions exported by the package.

Setup / removal

Use the setup and remove functions to migrate up and down respectively. These functions needs a PoolClient instance from the pg package. You can get one from the withPgClient function from the WorkerUtils, JobHelpers or Helpers type.

Example:

import { makeWorkerUtils } from "graphile-worker"
import { 
  setup as graphileWorkerExtensionSetup,
  remove as graphileWorkerExtensionRemove,
} from "graphile-worker-extension"

import graphileConfig from "./graphile.config"

async function main() {
    const workerUtils = await makeWorkerUtils({
        preset: graphileConfig
    })
    
    await workerUtils.withPgClient(graphileWorkerExtensionSetup())
    
    // Create some jobs...
    
    await workerUtils.withPgClient(graphileWorkerExtensionRemove())
    await workerUtils.release()
}

main().catch(err => {
    console.log(err)
    process.exit(1)
})

Saving job output

• wrapJob: An optional function that allows the return value of a job to be saved to be used by the parent. If an intermediate result was stored and the function doesn't return anything, the stored result will be overwritten with null

  Examples:

  // tasks/get-four.ts
  import { wrapJob } from "graphile-worker-extension"
  
  export default wrapJob<"get-four">((payload, _helpers) => 4)

  // worker.ts
  import { run } from "graphile-worker"
  import { wrapJob } from "graphile-worker-extension"
  
  import graphileConfig from "./graphile.config"
  
  async function main() {
      const runner = await run({
          preset: graphileConfig,
          taskList: {
              getFour: wrapJob<"getFour">((payload, _helpers) => 4)
          },
          forbiddenFlags: rateLimiter.getForbiddenFlags,
      });
  
      await runner.promise;
  }
  
  main().catch(err => {
      console.log(err)
      process.exit(1)
  })

• updateJobProgress: Updates the result stored in the database. The value can be anything that is JSON serializable.

  Example:

  // worker.ts
  import { run, type Task } from "graphile-worker"
  import { updateJobProgress } from "graphile-worker-extension"
  
  import graphileConfig from "./graphile.config"
  
  const getFour: Task<"getFour"> = async (_, helpers) => {
      await helpers.withPgClient(updateJobProgress(helpers.job, 4))
  }
  
  async function main() {
      const runner = await run({
          preset: graphileConfig,
          taskList: {
              getFour
          },
          forbiddenFlags: rateLimiter.getForbiddenFlags,
      });
  
      await runner.promise;
  }
  
  main().catch(err => {
      console.log(err)
      process.exit(1)
  })

Job creation

• addJobTree: Insert a job tree. All leaf jobs are started at the same time. All options from addJob can be passed.

  Example:

  // index.ts
  import { makeWorkerUtils } from "graphile-worker"
  import { 
  setup as graphileWorkerExtensionSetup,
  remove as graphileWorkerExtensionRemove,
  addJobTree
  } from "graphile-worker-extension"
  
  import graphileConfig from "./graphile.config"
  
  async function main() {
      const workerUtils = await makeWorkerUtils({
          preset: graphileConfig
      })
      
      await workerUtils.withPgClient(graphileWorkerExtensionSetup)
      
      await addJobTree({
          identifier: "root-job",
          children: [
              {
                  identifier: "job1",
                  payload: {
                      hello: "world"
                  },
                  onFailure: "ignore"
              },
              {
                  identifier: "job2",
                  onFailure: "remove"
              },
              {
                  identifier: "send-mail",
                  payload: {
                      to: "john.doe@example.com",
                      msg: "Hello"
                  },
                  // Default
                  onFailure: "fail-parent"
              }
          ]
      })
      
      await workerUtils.withPgClient(graphileWorkerExtensionRemove)
      await workerUtils.release()
  }
  
  main().catch(err => {
      console.log(err)
      process.exit(1)
  })

Result retrieval

• getChildrenValues: Retrieves the results of successful children as an object with the job IDs as keys. The function takes the job and query properties of the helpers object passed to the job.

  Example

  // worker.ts
  import { run } from "graphile-worker";
  import { getChildrenValues, wrapJob } from "graphile-worker-extension";
  
  import graphileConfig from "./graphile.config";
  
  const writeReport = wrapJob<"report">(async (payload, helpers) => {
      helpers.logger.info(`Writing report for user#${payload.userId}`);
  
      const childrenResults = await getChildrenValues(
          helpers.job,
          helpers.query
      )
  
      const {
          rows: [report],
      } = await helpers.query(
          /* sql */ `UPDATE reports SET data = $1::json, completed = true WHERE id = $2`,
          [JSON.stringify(Object.values(childrenResults).flat()), payload.userId]
      );
  
      return report;
  });
  
  async function main() {
      const runner = await run({
          preset: graphileConfig,
          taskList: {
              report: writeReport,
          },
      });
  
      await runner.promise;
  }
  
  main().catch((err) => {
      console.error(err);
      process.exit(1);
  });

• getFailedChildrenValues: Retrieves the results of failed children as an object with the job IDs as keys. Usage is the same as getChildrenValues

• recoverJobProgress: Retrieves the intermediate result from the previous attempts. Returns null on the first attempt.

  Example:

  // dummy-job.ts
  import { run } from "graphile-worker";
  import { recoverJobProgress } from "graphile-worker-extension";
  
  export default async (payload, helpers) => {
      helpers.logger.info("Starting dummy job");
  
      const previousResults = (await recoverJobProgress<unknown[]>(helpers.job, helpers.query)) ?? []
  
      // Do something...
  }