Adding HEALTHCHECK for docker container

[ViBiOh]

No description provided.

[Dynom]

Hi @ViBiOh,

Thanks for your time and effort!

I need to ponder this change for a bit as I'm not intimately familiar with the HEALTHCHECK directive and it's implications on installations.

I'm interested to learn what this means for Imaginary. Imaginary exposes a health-point that can be externally consumed and the docker run command fails if it fails to start the binary. afaik there isn't an in-between state that needs monitoring and the start-time is very short (no need to wait for something long, like a db starting or something network related). It sounds like the HEALTHCHECK is mostly valuable for multi-process containers (which Imaginary hasn't).

I will brush up on it and will report back later.

[Dynom]

Since it's a Dockerfile change, would you mind using release/next as a base for your PR? We're currently in the process of a fairly large overhaul of the Docker setup.

https://github.com/h2non/imaginary/tree/release/next

[jbergstroem]

I'm generally not a fan of using curl for HEALTHCHECK. Also, worth mentioning that this is not in OCI yet.

[ViBiOh]

Hi, I was trying to monitor the appropriate way to check if the service is up and running. If checking the PID 1 is the way, it's ok for me.

I'm using imaginary as a sidecar for a file browser. The port is not exposed and HTTP only accessible from inside the appropriate network.

[Dynom]

Hi, I was trying to monitor the appropriate way to check if the service is up and running. If checking the PID 1 is the way, it's ok for me.

I'm using imaginary as a sidecar for a file browser. The port is not exposed and HTTP only accessible from inside the appropriate network.

Understandable setup! Is it acceptable for your setup to roll your own Dockerfile using:

FROM h2non/imaginary:<tag>

RUN DEBIAN_FRONTEND=noninteractive apt-get update && apt-get install -y curl

HEALTHCHECK --retries=10 CMD curl --fail http://localhost:$PORT/health

This will provide you with the desired functionality, without forcing everybody to use it. Otherwise everybody else need to roll a similar Dockerfile and reset HEALTCHECK to a noop.

[ViBiOh]

I've ended using following config in my docker-compose

    healthcheck:
      test: ["CMD", "ps", "-p", "1", "--no-headers"]
      retries: 10