Healthcheck for docker container

[italktothewind]

Currently it's impossible to do a healthcheck in the Restheart container because you can't execute something like a curl. Please provide some method to check the container's health.

[mkjsix]

If you want to healthcheck RESTHeart then you can call the /ping URI. I don't see why you should want to check the container health from within the container itself, it's not a good practice. If you instead meant to check the health of another container, then it's not a good practice either, you should monitor containers with an external monitoring system. If I misunderstood what you mean please be more specific in your request.

[italktothewind]

I have the following problem. I have this docker compose:

version: '3.4'
services:

  mongodb:
    image: mongo:4.2
    ports:
      - 27017:27017

  restheart:
    image: softinstigate/restheart:3.10.0
    ports:
      - 8082:8080
    volumes:
      - ./restheart:/opt/restheart/etc:ro
    depends_on:
      - mongodb
    healthcheck:
      test: ["NONE"]

I want to put a healthcheck in restheart (instead of NONE), but all the commands I tried failed. Then I tried to execute something like curl using docker exec, but I got:

OCI runtime exec failed: exec failed: container_linux.go:346: starting container process caused "exec: \"curl\": executable file not found in $PATH": unknown

[italktothewind]

From the dockerfile:

FROM openjdk:8u111-jre-alpine
RUN apk upgrade --update && apk add --update libstdc++ curl ca-certificates bash
...

seems that curl is already installed, but I can't acces it.

[mkjsix]

I see what you mean. I don't really know why the container does not find curl, it's RESTHeart version 3 and I'm not using it since a lot. The curl command should be installed under /usr/bin/curl (it was Alpine Linux), then maybe try providing the healthcheck with the absolute path to curl. I will give it a try...

[mkjsix]

I checked the branch and RESTHeart 3.10 was not based on Alpine Linux but already on gcr.io/distroless/java:8 so there's literally nothing installed on it, not even the sh shell. It's a distribution radically focused on security. See https://github.com/GoogleContainerTools/distroless.

Dockerfile: https://github.com/SoftInstigate/restheart/blob/3.10.0/Dockerfile

Unfortunately the only option is to build your own image of RESTHeart, using a different base image. You can refer to previous versions, when we were still using Alpine.

[italktothewind]

It's a pity to build images that are a pain in the neck for the devs. Even for very standard stuff, like adding a healthcheck. A lot of products have different images, for example RabbitMQ has an official image for development (including a webserver with an UI) and another image for production. Of course I can do it by myself, but it's not the same, I'm just using restheart for integration tests. Thanks for the information, I will try to use an older version, hope it works with mongo 4.2.

[italktothewind]

Previous version, 3.9.0, is not distroless and works fine. I fix it downgrading it. Thanks for your help.

[mkjsix]

@italktothewind This is an open source project mostly developed by a couple of persons in their spare time, it's not sponsored by a big company. If you want contribute we are always open to accept PRs. Take care.

[mkjsix]

Please, have a look at RESTHeart 5.0.1 release notes.

[italktothewind]

GREAT NEWS :-)