# Docker
## Useful commands
Build Image
```bash
docker build . -t $TAG
# no cache: --no-cache
# build args (like env vars): --build-arg NPM_TOKEN=$NPM_TOKEN
```
With file in monorepo:
```bash
docker build -t $TAG -f $FILE --build-arg NAME=value .
```
Check size
```bash
# save image
docker save $NAME -o $OUTPUT_FILE.tar
# login to image and run the following:
# root
du -h -s app/ bin/ dev/ etc/ home/ lib/ lib64/ media/ opt/ run/ sbin/ srv/ sys/ tmp/ usr/ var/
# usr
du -h -s bin/ include/ lib libexec/ local/ sbin/ share/
# app
du -h -s apps/ node_modules/ packages/
# by size
du -h | sort -h
```
Check vulnerabilities
```bash
trivy image $TAG --scanners vuln
```
Run Image
```bash
# --net=host publishes host network to container, use it only for testing!
docker run --name $NAME -p 8080:8080 --net=host -d $TAG
# stop it with
docker stop $NAME
```
Monitoring
```bash
# images
docker images
# running container
docker ps
# logs
docker logs -f --tail 100 $NAME
# watch running instances
watch docker ps
```
Clean up (more [here](https://renehernandez.io/snippets/cleaning-local-docker-cache/))
```bash
# Removing unused containers
docker ps --filter status=exited --filter status=dead -q
docker rm $(docker ps --filter=status=exited --filter=status=dead -q)
# Removing dangling images
docker images --filter dangling=true -q
docker rmi $(docker images --filter dangling=true -q)
```
Navigate docker image
```bash
docker run -it $TAG sh
```
Stop all running containers
```bash
docker stop $(docker ps -a -q)
```
Remove all containers
```bash
docker rm $(docker ps -aq)
```
## Dockerfile Best Practices
Use the right Node base image:
*
*
Using dumb-init
```dockerfile
# https://github.com/Yelp/dumb-init
RUN apk add dumb-init
```
Avoid calling `npm`, use instead:
```dockerfile
EXPOSE 8080
CMD ["dumb-init", "node", "dist/index.js"]
```
Non user example:
```dockerfile
FROM node:10-alpine
RUN mkdir -p /home/node/app/node_modules && chown -R node:node /home/node/app
WORKDIR /home/node/app
COPY package*.json ./
USER node
RUN npm install
COPY --chown=node:node . .
EXPOSE 8080
CMD [ "node", "app.js" ]
```
## Docker Compose
Local build:
```yaml
services:
web:
build:
context: project-root
dockerfile: dockerfile-path
ports:
- "8080:8080"
```
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