Pulumi custom component for running local commands

readme.md

Use case

This can be useful for running a custom build command to generate assets which will be used as part of your Pulumi deployment.

Example

Run a command, specifying ENV variables based on the output of another resource.

const clientBuild = new Exec('demo-client-build', {
  command: 'cd ../client && yarn build',
  options: {
    env: pulumi
      .all([userPool.id, authClient.id])
      .apply(([cognitoUserPoolId, userPoolWebClientId]) =>
        Object.assign(
          {
            REACT_APP_USER_POOL_ID: cognitoUserPoolId,
            REACT_APP_USER_POOL_WEB_CLIENT_ID: userPoolWebClientId,
          },
          process.env,
        ),
      ),
  },
});

This resource can then be explicitly depended on to ensure it completes before subsequent steps.

exec.ts

import * as pulumi from '@pulumi/pulumi';
import { exec, ExecOptions } from 'child_process';

export type ExecArgs = {
  command: pulumi.Input<string>;
  options?: pulumi.Lifted<ExecOptions>;
};

export class Exec extends pulumi.ComponentResource {
  stdout: pulumi.Output<string>;
  stderr: pulumi.Output<string>;

  constructor(
    name: string,
    args: ExecArgs,
    opts?: pulumi.ComponentResourceOptions,
  ) {
    super('local:child_process:Exec', name, {}, opts);

    const result = pulumi.all([args.command, args.options || {}]).apply(([command, options]) =>         
    new Promise<[string, string]>((resolve, reject) => {
      exec(command, options, (err, stdout, stderr) => {
        if (err !== null) {
          reject(err);
        } else {
          resolve([stdout, stderr]);
        }
      });
    }),);

    this.stdout = result.apply(([stdout,]) => stdout);
    this.stderr = result.apply(([,stderr]) => stderr);

    this.registerOutputs({
      stdout: this.stdout,
      stderr: this.stderr,
    });
  }
}