static-healthcheck

This project was created to add healthcheck in docker images without installing curl or other tools
This is useful for statically compiled images FROM scratch for example

Standalone Usage

Usage of /healthcheck:
  -http value
        httpcheck: ex: my.domain.com:80
  -tcp value
        tcpcheck: ex: my.domain.com:80

These flags accept multiple values :
/healthcheck -tcp my.domain.com:80 -http my2.domain.com:80 -http 127.0.0.1:8080

-http do a GET of the provided URI : return OK if response code < 400
-tcp verify that the privided host:port respond

Return 0 if all checks are OK
Return 1 otherwise

Dockerfile Usage

In fact, you only need two lines in your existing Dockerfile to add this

COPY        --from=wtfcoderz/static-healthcheck /healthcheck /
HEALTHCHECK --interval=5s --timeout=2s --start-period=1s --retries=2 CMD ["/healthcheck", "-tcp", "127.0.0.1:80"]

Dockerfile example for Caddy server with a Healthcheck

FROM  alpine:latest as build
RUN   apk add --no-cache curl \
      && curl --insecure --silent --show-error --fail --location \
        --header "Accept: application/tar+gzip, application/x-gzip, application/octet-stream" -o - \
        "https://caddyserver.com/download/linux/amd64?plugins=http.git,http.cgi" \
        | tar --no-same-owner -xz caddy \
      && chmod 0755 /caddy \
      && /caddy -version

FROM  scratch
COPY  --from=build /caddy /caddy
COPY        --from=wtfcoderz/static-healthcheck /healthcheck /
HEALTHCHECK --interval=5s --timeout=2s --start-period=1s --retries=2 CMD ["/healthcheck", "-tcp", "127.0.0.1:2015"]
COPY  Caddyfile /etc/Caddyfile
CMD   ["/caddy", "-conf","/etc/Caddyfile","--log","stdout"]