backfill/src/commandRunner.ts

import * as execa from "execa";
import * as fs from "fs-extra";
import { logger } from "backfill-logger";
import { outputFolderAsArray } from "backfill-config";

export type ExecaReturns = execa.ExecaChildProcess;
export type BuildCommand = () => Promise<ExecaReturns | void>;

export function getRawBuildCommand(): string {
  return process.argv.slice(2).join(" ");
}

export function createBuildCommand(
  buildCommand: string[],
  clearOutputFolder: boolean,
  outputFolder: string | string[]
): () => Promise<ExecaReturns | void> {
  return async (): Promise<ExecaReturns | void> => {
    const parsedBuildCommand = buildCommand.join(" ");

    if (!parsedBuildCommand) {
      throw new Error("Command not provided");
    }

    // Clear outputFolder to guarantee a deterministic cache
    if (clearOutputFolder) {
      await Promise.all(
        outputFolderAsArray(outputFolder).map(folder => fs.remove(folder))
      );
    }

    // Set up runner
    logger.profile("buildCommand:run");
    const runner = execa(parsedBuildCommand, {
      shell: true,
      ...(process.env.NODE_ENV !== "test" ? { stdio: "inherit" } : {})
    });

    return (
      runner
        // Add build time to the performance logger
        .then(() => {
          logger.setTime("buildTime", "buildCommand:run");
        })
        // Catch to pretty-print the command that failed and re-throw
        .catch(err => {
          if (process.env.NODE_ENV !== "test") {
            logger.error(`Failed while running: "${parsedBuildCommand}"`);
          }
          throw err;
        })
    );
  };
}