Ensure 'HEALTHCHECK' is set

Risk Level: informational
Platform: Docker
Spectral Rule ID: DOCKR019

REMEDIATION

The HEALTHCHECK instruction tells Docker how to test a container to check that it is still working. This can detect cases such as a web server that is stuck in an infinite loop and unable to handle new connections, even though the server process is still running.
When a container has a healthcheck specified, it has a health status in addition to its normal status. This status is initially starting. Whenever a health check passes, it becomes healthy (whatever state it was previously in). After a certain number of consecutive failures, it becomes unhealthy.
The options that can appear before CMD are:

• --interval=DURATION (default: 30s)
• --timeout=DURATION (default: 30s)
• --start-period=DURATION (default: 0s)
• --retries=N (default: 3)

The health check will first run interval seconds after the container is started, and then again interval seconds after each previous check completes.
If a single run of the check takes longer than timeout seconds then the check is considered to have failed.

FROM node:alpine
WORKDIR /usr/src/app
COPY package*.json ./
RUN npm install
COPY . .
EXPOSE 3000
+ HEALTHCHECK --interval=5m --timeout=3s CMD curl -f http://localhost/ || exit 1 
CMD ["node","app.js"]

Read more:

• https://docs.docker.com/engine/reference/builder/#healthcheck