PR remarks

This commit is contained in:
Kevyn Bruyere
2020-07-29 09:02:28 +02:00
parent 54e206cde0
commit 01ff3a75c8
2 changed files with 12 additions and 4 deletions

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@ -1097,7 +1097,7 @@ Bear in mind that with the introduction of the new V8 engine alongside the new E
**TL;DR:** use `CMD ['node','server.js']` to start your app. This prevents problems with child-process, signal handling and avoid creating unnecessary processes.
**Otherwise:** You'll have hard shutdowns, possibly losing current requests and/or data
**Otherwise:** When no signals are passed in you'll have hard shutdowns, possibly losing current requests and/or data
[**Read More: Bootstrap container using node command, avoid npm start**](/sections/docker/bootstrap-using-node.md)

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@ -2,18 +2,26 @@
## One paragraph explainer
We are used to see code examples where folks start their app using `CMD 'npm start'`. This is a bad practice. The `npm` binary will not forward signals to your app which prevents graceful shutdown (see #716). If you are using Child-processes they wont be cleaned up correctly in case of unexpected shutdown, leaving zombie processes on your host. `npm start` also results in having an extra process for no benefit. To start you app use `CMD ['node','server.js']`.
We are used to see code examples where folks start their app using `CMD 'npm start'`. This is a bad practice. The `npm` binary will not forward signals to your app which prevents graceful shutdown (see [/sections/docker/graceful-shutdown.md]). If you are using Child-processes they wont be cleaned up correctly in case of unexpected shutdown, leaving zombie processes on your host. `npm start` also results in having an extra process for no benefit. To start you app use `CMD ['node','server.js']`. If your app spawns child-processes also use `TINI` as an entrypoint.
### Code example
```dockerfile
FROM node:12-slim AS build
# Add Tini if using child-processes
ENV TINI_VERSION v0.19.0
ADD https://github.com/krallin/tini/releases/download/${TINI_VERSION}/tini /tini
RUN chmod +x /tini
WORKDIR /usr/src/app
COPY package.json package-lock.json ./
RUN npm ci --production && npm clean cache --force
CMD ['node', 'server.js']
ENTRYPOINT ["/tini", "--"]
CMD ["node", "server.js"]
```
### Antipatterns
@ -27,7 +35,7 @@ COPY package.json package-lock.json ./
RUN npm ci --production && npm clean cache --force
# dont do that!
CMD npm start
CMD "npm start"
```
Using node in a single string will start a bash/ash shell process to execute your command. That is almost the same as using `npm`