Heroku Go 应用崩溃

Question

正在关注 this tutorial ，一切都在本地工作。在我将我的应用程序部署到 Heroku 并在浏览器上访问该应用程序后，我收到了一个503 错误和消息:

Application Error An error occurred in the application and your page could not be served. Please try again in a few moments. If you are the application owner, check your logs for details.

日志说:

2015-09-08T16:31:53.976824+00:00 heroku[web.1]: State changed from crashed to starting
2015-09-08T16:31:56.174376+00:00 heroku[web.1]: Starting process with command `mywebsite`
2015-09-08T16:31:59.312461+00:00 app[web.1]: Listening on port: 39461
2015-09-08T16:32:56.471550+00:00 heroku[web.1]: Error R10 (Boot timeout) -> Web process failed to bind to $PORT within 60 seconds of launch
2015-09-08T16:32:56.471550+00:00 heroku[web.1]: Stopping process with SIGKILL
2015-09-08T16:32:57.390752+00:00 heroku[web.1]: Process exited with status 137
2015-09-08T16:32:57.404208+00:00 heroku[web.1]: State changed from starting to crashed
2015-09-08T16:32:57.645135+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=boiling-eyrie-6897.herokuapp.com request_id=ec26... fwd="xx.xxx.xxx.xxx" dyno= connect= service= status=503 bytes=
2015-09-08T16:32:58.233774+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=boiling-eyrie-6897.herokuapp.com request_id=ef40...fwd="xx.xxx.xxx.xxx" dyno= connect= service= status=503 bytes=

我知道错误是什么，但是这么小的教程应用程序怎么会导致启动超时 (R10)？

我怎样才能更好地调试它并修复应用程序使其运行？

Answer 1

当您通过 heroku 部署应用时，它不允许您指定端口号。
换句话说，您不能将 Web 服务的端口 号指定为8000 或其他名称，heroku 在运行时决定端口号。
所以，你不能使用下面的代码:

    log.Fatal(http.ListenAndServe(":8000", router))

你可以做的是，获取 heroku 的运行时端口。
简而言之，只需使用以下代码:

    log.Fatal(http.ListenAndServe(":" + os.Getenv("PORT"), router))