HTTP Health Check for Docker

I just published a little tool called htcheck (docker-health-go project) on github: . This being my first Go program, be kind to me, should there be better ways to implement it. 

It is intended as a very simple HTTP health check client for use in Docker health checks. Motivation, why this program?

When using docker directly or via docker-compose, you can and should define a health check, so that docker knows that the process it is running is doing well. There are a couple of libraries to provide a HTTP health endpoints for Go, such as [] and also Java offers with Spring Boot Actuator corresponding framework.

But on the client side, you still need to use curl or the outdated wget to perform the check. If you ever checked, which dependencies curl and thus libcurl4 brings with it, you might wonder if this is worth the ballast just to do a simple HTTP get with an exit code. Libcurl brings openldap libraries into the image and what not. So this little decent project provides a special-purpose HTTP client to use for health checks in docker or elsewhere instead of throwing a general-purpose HTTP client at the job.

It supports making a HTTP GET request to a URL and reading a JSON document back and checking for a value in it using a jq-like path expression.

Simple sample usage in Dockerfile:

COPY ./htcheck /usr/bin/

HEALTHCHECK --interval=5m --timeout=3s CMD htcheck -u http://localhost/ || exit 1

Sample usage for Spring Boot actuator health endpoint, which normally serve a JSON document in the form:

    "status" : "UP"
So using the JSON path feature, we can compare against a expected value:
COPY ./htcheck /usr/bin/

HEALTHCHECK --interval=5m --timeout=3s CMD htcheck -u http://localhost/health -p .status -v UP || exit 1

Licenses are checked and documented in the README. Thanks to the dependency projects [] and [] that were made use of. Probably some features are still missing, but as a first shot, it should serve. S’il vous plaît!

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