diff --git a/.changeset/rich-pillows-cough.md b/.changeset/rich-pillows-cough.md new file mode 100644 index 0000000000..959eb69214 --- /dev/null +++ b/.changeset/rich-pillows-cough.md @@ -0,0 +1,12 @@ +--- +'@backstage/backend-common': patch +--- + +Make sure that server builder `start()` propagates errors (such as failing to bind to the required port) properly and doesn't resolve the promise prematurely. + +After this change, the backend logger will be able to actually capture the error as it happens: + +``` +2021-11-11T10:54:21.334Z backstage info Initializing http server +2021-11-11T10:54:21.335Z backstage error listen EADDRINUSE: address already in use :::7000 code=EADDRINUSE errno=-48 syscall=listen address=:: port=7000 +``` diff --git a/packages/backend-common/src/service/lib/ServiceBuilderImpl.ts b/packages/backend-common/src/service/lib/ServiceBuilderImpl.ts index ed16c9c9a7..885baba54b 100644 --- a/packages/backend-common/src/service/lib/ServiceBuilderImpl.ts +++ b/packages/backend-common/src/service/lib/ServiceBuilderImpl.ts @@ -174,27 +174,27 @@ export class ServiceBuilderImpl implements ServiceBuilder { const server: http.Server = httpsSettings ? await createHttpsServer(app, httpsSettings, logger) : createHttpServer(app, logger); + const stoppableServer = stoppable(server, 0); + + useHotCleanup(this.module, () => + stoppableServer.stop((e: any) => { + if (e) console.error(e); + }), + ); return new Promise((resolve, reject) => { - app.on('error', e => { - logger.error(`Failed to start up on port ${port}, ${e}`); + function handleStartupError(e: unknown) { + server.close(); reject(e); + } + + server.on('error', handleStartupError); + + server.listen(port, host, () => { + server.off('error', handleStartupError); + logger.info(`Listening on ${host}:${port}`); + resolve(stoppableServer); }); - - const stoppableServer = stoppable( - server.listen(port, host, () => { - logger.info(`Listening on ${host}:${port}`); - }), - 0, - ); - - useHotCleanup(this.module, () => - stoppableServer.stop((e: any) => { - if (e) console.error(e); - }), - ); - - resolve(stoppableServer); }); }