是否可以在没有web dyno的情况下将Node.js应用程序部署到Heroku？ [英] Is it possible to deploy a Node.js application to Heroku without a web dyno?

问题描述

对于某些背景故事和参考，以下是一些Heroku文档页面的引用。

For some backstory and reference, here are some quotes from a few Heroku documentation pages.

来自 Heroku Node.js支持>激活：

当应用程序在根目录中有 package.json 文件时，将使用Heroku Node.js buildpack。

The Heroku Node.js buildpack is employed when the application has a package.json file in the root directory.

来自 Heroku Node.js支持>默认Web流程类型：

首先，Heroku查找 Procfile 指定您的流程类型。

如果没有 Procfile 出现在应用程序的根目录中，您的Web进程将通过运行 npm start ，[...]

If no Procfile is present in the root directory of your app during the build process, your web process will be started by running npm start, [...]

来自流程类型和Procfile>流程类型作为模板：

Procfile包含许多流程类型声明，每个声明在一条新线上。每个流程类型都是在启动该流程类型的dyno时执行的命令声明。

A Procfile contains a number of process type declarations, each on a new line. Each process type is a declaration of a command that is executed when a dyno of that process type is started.

例如，如果 web 声明了进程类型，然后当启动此类型的dyno时，将执行与 web 进程类型关联的命令。例如，这可能意味着启动Web服务器。

For example, if a web process type is declared, then when a dyno of this type is started, the command associated with the web process type, will be executed. This could mean starting a web server, for example.

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我有一个 package.json 根目录中的文件（将激活Node.js buildpack），我还包含了一个 Procfile 在根目录中包含以下内容：

---

I have a package.json file in the root (which will activate the Node.js buildpack), and I've also included a Procfile in the root with the following contents:

service: npm start

我认为不定义 web dyno会导致它无法创建;只应按照 Procfile 中声明的配置创建服务 dyno。

I would assume that not defining a web dyno would cause it to not be created; only the service dyno should be created, following the configuration declared in the Procfile.

相反，发生的事情是有效 网络 dyno 使用<$自动创建c $ c> npm start 和无效 服务 dyno是使用中的定义创建的Procfile 。然后我不得不：

Instead, what happened is that an active web dyno was automatically created using npm start and an inactive service dyno was created using the definition in Procfile. I then had to:

• heroku ps：scale web = 0


• heroku ps：规模服务= 1

• heroku ps:scale web=0
• heroku ps:scale service=1

我绝对可以想象想在Heroku上运行一个Node.js服务应用程序，该应用程序不接受任何传入连接，只接收传出连接。有没有办法配置Node.js buildpack，以便在未定义一个时自动创建 web dyno？我查看了大量文档，寻找方法：（1）如此定义或（2） 删除自动生成 web dyno;但是，我还没有找到任何东西。

I can definitely imagine wanting to run a Node.js "service" application on Heroku that does not accept any incoming connections, only making outgoing ones. Is there a way to configure the Node.js buildpack to not automatically create a web dyno when one is not defined? I've looked through lots of documentation looking for a way to either: (1) define it as such or (2) remove the automatically generated web dyno; but, I haven't found anything.

感谢您的帮助！

推荐答案

我最后在Heroku上打开了一张帮助台票。得到了他们的回复，所以我会在这里发布。谢谢Heroku的支持！

I ended up opening a helpdesk ticket with Heroku on this one. Got a response from them, so I'll post it here. Thanks Heroku support!

简短的回答是，不，目前你需要 heroku scale web = 0 service = 1 以便在没有公共 web 进程的情况下运行服务。有关更长的解释：

The short answer is that, no, currently you'll need to heroku scale web=0 service=1 in order to run a service without a public web process. For a longer explanation:

早期，Node.js Buildpack检查是否存在 Procfile 和如果缺少，则使用 web：npm start 创建一个默认值。这使得在没有Web进程的情况下创建应用程序变得容易，因为您可以提供定义某些进程的 Procfile ，省略 web 从列表中。

Early on, the Node.js Buildpack checked for the presence of a Procfile and, if missing, created a default one with web: npm start. This made it easy to create apps without a web process, since you could just provide a Procfile that defined some processes, omitting web from the list.

然而，随着越来越多的用户需要构建包的数组而不是单个数组，该解决方案产生了问题。 Node是最受欢迎的第一个buildpack，因为Java，Python，PHP和Ruby应用程序经常使用它来构建前端资产。每当没有 Procfile 的应用程序首先运行Node，然后运行另一个buildpack时，Node会注入自己的默认 Procfile （ web：npm start ），然后第二个buildpack不会创建默认的 Procfile ，因为文件系统中已存在。因此，当应用程序中缺少一个默认的Procfile时，会为多语言应用程序创建下游问题。

However, as more and more users needed arrays of buildpacks instead of a single one, that solution created issues. Node is the most popular first buildpack, since it's frequently used by Java, Python, PHP, and Ruby apps to build front-end assets. Whenever an app without a Procfile ran Node first, and another buildpack second, Node would inject its own default Procfile (web: npm start), and the second buildpack would then not create its default Procfile as one already existed in the filesystem. So injecting a default Procfile when one is missing from the app creates problems downstream for multilingual apps.

所以，我们停止创建默认的Procfile，而是在bin / release 中使用default_process_types。这解决了后续buildpacks继承错误的默认Procfiles的问题，但由于 default_process_types 是扩展而不是被替换 code> Procfile 进程列表，在 Procfile web 进程的应用程序>将合并默认的 web 进程。这就是为什么 web 即使没有也会出现web 输入 Procfile 。

So, we stopped creating a default Procfile and instead used default_process_types in bin/release. This fixes the issue of subsequent buildpacks inheriting incorrect default Procfiles, but since default_process_types is extended rather than replaced by the Procfile process list, apps without a web process defined in their Procfile will get the default web process merged in. This is why web appears even without a web entry in Procfile.

我们也不想让任何客户感到惊讶意外的账单。有些应用程序有许多进程类型，其中一些仅偶尔运行，一些仅限于单个实例，一些需要按比例放大，等等，因此将所有内容默认为1而不是0可能会导致额外的计费作为应用程序故障。这就是默认情况下非Web进程缩放为零的原因。

We also don't want to surprise any customers with unexpected bills. Some apps have many process types, some of which are only to be run occasionally, some limited to a single instance, some which need to be scaled up and down, etc, so defaulting everything to 1 rather than 0 could cause extra billing as well as app malfunctions. This is why non-web processes are scaled to zero by default.

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