Add healthcheck

[vincentchalamon]

Cf. https://docs.docker.com/engine/reference/builder/#healthcheck

[ImreSamu]

@vincentchalamon :
imho: it would be better if the official postgres image will support this feature ( for compatibility reason)

• see Feature request: add HEALTHCHECK docker-library/postgres#282 "Feature request: add HEALTHCHECK"

[vincentchalamon]

@ImreSamu That would be awesome (not just on postgres). But if docker-library/postgres#282 is rejected, current PR will improve current Docker image.

Status: waiting for docker-library/postgres#282 to be accepted or rejected.

[md5]

Can you please make these changes in the Dockerfile.template file as well?

Also, the Makefile needs to be updated to copy the healthcheck.sh script from a shared source of truth, like the other scripts.

[md5]

Let's remove this line and add a section to the README.md telling users how to enable the health check command using either HEALTHCHECK CMD or the --health-cmd command line switch (I think it would make sense to link to https://docs.docker.com/engine/reference/run/#healthcheck).

The README.md section should describe what docker-healthcheck does and perhaps possible reasons why someone would want a more specific healthcheck for their application, such as the fact that it can't test connectivity from outside the container.

[md5]

If you chmod the actual file in the repository, this line should not be necessary.