Unable to add healthcheck

[mbw2001]

I often see this container fail after a server reboot, which in turn makes all containers using this fail. If I restart this container all is well.

I would like to implement a simple healthcheck like:

healthcheck:
    test: ["CMD", "wget", "-nv -t1 --spider 'http://localhost:4181/' || exit 1"]
    interval: 30s
    timeout: 10s
    retries: 5

But I don't know how to implement something like this for this baseimage as I cannot get access to any sort of shell, wget, curl or similar.

A healthcheck implementet directly in the image would be great, but if anyone successfully added their own in docker-compose that would work as well.

[mbw2001]

These guys have implemented a quite simple solution: https://github.com/Soluto/golang-docker-healthcheck-example

Rebuilding the container with the following Dockerfile works:

FROM golang:1.13-alpine as builder

# Setup
RUN mkdir -p /go/src/github.com/thomseddon/traefik-forward-auth
WORKDIR /go/src/github.com/thomseddon/traefik-forward-auth

# Add libraries
RUN apk add --no-cache git

# Copy & build
ADD . /go/src/github.com/thomseddon/traefik-forward-auth/
RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 GO111MODULE=on go build -a -installsuffix nocgo -o /traefik-forward-auth github.com/thomseddon/traefik-forward-auth/cmd
RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 GO111MODULE=on go build -a -installsuffix nocgo -o /healthcheck github.com/Soluto/golang-docker-healthcheck/healthcheck

# Copy into scratch container
FROM scratch
COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
COPY --from=builder /traefik-forward-auth ./
COPY --from=builder /healthcheck ./healthcheck
ENTRYPOINT ["./traefik-forward-auth"]

HEALTHCHECK --interval=1s --timeout=1s --start-period=2s --retries=3 CMD [ "/healthcheck" ]

But of course it would be better to simply add the file to the existing repo, rather than depend on a third party repo. The file is very simple:

package main

import (
	"fmt"
	"net/http"
	"os"
)

func main() {
	_, err := http.Get(fmt.Sprintf("http://127.0.0.1:%s/health", os.Getenv("PORT")))
	if err != nil {
		os.Exit(1)
	}
}

Because of the implementation I had to add an environment variable PORT to match the current port, so adding to this repo and using the existing variable for port would be better.

[kaysond]

See https://github.com/thomseddon/traefik-forward-auth/discussions/209