[legacy-framework] Fix to not build custom server during blitz start

[mabadir]

Closes: blitz-js/legacy-framework#267

What are the changes and their implications?

• Building Custom Server during Blitz Build
• startCustomServer function, now doesn't build by default.
• Introduce a separate buildCustomServer fn

Feature Checklist

• Integration test added (see test docs if needed)
• Documentation added/updated (submit PR to blitzjs.com repo)

[flybayer]

Not sure if you are done? Mark as not-draft if you are done.

However, this doesn't fully address the original issue. The custom server is still being built on blitz start. I think we should separate the function into buildCustomServer and startCustomServer.

[mabadir]

Yes sorry, I didn't fully understand the main concern from the original issue. I will review this PR today and will push few updates. Sorry about that.

[flybayer]

Looking good! But this is a regression for blitz dev use case.

Here's the full list. Sorry, I should have put this earlier.

• blitz build builds custom server
• blitz start runs but does not build custom server
• blitz dev should both build and run custom server (this is working correctly in existing code, but it's not on this PR)

[mabadir]

I think adding:
await buildCustomServer() to this line will solve it:

blitz/packages/server/src/dev.ts

Line 48 in 8eb1509

[flybayer]

That handles initial build, but not watch. Did you test blitz dev?

I think we should conditionally do spawnServer() vs

esbuild.build(esbuildOptions).then(() => {
      spawnServer()
})

based on watch flag. Currently esbuildOptions in this function are not used and so hot reload doesn't work.

[mabadir]

You're right, I rushed this one in. This is what I am coming up with now.

export function startCustomServer(
    cwd: string,
    config: ServerConfig,
    {watch}: CustomServerOptions = {},
) {
  const serverBuildPath = getCustomServerBuildPath()

  let spawnEnv = getSpawnEnv(config)
  if (config.env === "prod") {
    spawnEnv = {...spawnEnv, NODE_ENV: "production"}
  }

  return new Promise<void>((res, rej) => {
    let process: ChildProcess

    const RESTART_CODE = 777777

    const spawnServer = () => {
      process = spawn("node", [serverBuildPath], {
        cwd,
        env: spawnEnv,
        stdio: "inherit",
      })
          .on("exit", (code: number) => {
            if (code === 0) {
              res()
            } else if (watch && code === RESTART_CODE) {
              spawnServer()
            } else {
              rej(`server.js failed with status code: ${code}`)
            }
          })
          .on("error", (err) => {
            console.error(err)
            rej(err)
          })
    }

    if (watch) {
      // Handle build & Starting server
      const esbuildOptions = getEsbuildOptions()
      esbuildOptions.watch = {
        onRebuild(error) {
          if (error) {
            log.error("Failed to re-build custom server")
          } else {
            log.newline()
            log.progress("Custom server changed - restarting...")
            log.newline()
            //@ts-ignore -- incorrect TS type from node
            process.exitCode = RESTART_CODE
            process.kill("SIGABRT")
          }
        },
      }
      // eslint-disable-next-line @typescript-eslint/no-floating-promises
      esbuild.build(esbuildOptions).then(() => {
        spawnServer()
      })
    } else {
      // No build required, Start server
      spawnServer()
    }
  })
}

[flybayer]

yay!

[blitzjs-bot]

Added @mabadir contributions for test