add --init to docker run

[tom-shan]

fix #195

Signed-off-by: tom-shan swt0008411@163.com

[marcdumais-work]

I got a permission issue at first. Got it working with a little tweak, so that the theia user has execute permission as well:

RUN chmod 555 /tini

[marcdumais-work]

I got a runtime exception when running tini from the entrypoint. Maybe the basic Ubuntu image is missing some dynamic library that's required? It worked with the statically linked version:

ADD https://github.com/krallin/tini/releases/download/${TINI_VERSION}/tini-static /tini

[marcdumais-work]

Hi @tom-shan ,

Thanks for this PR.

Looking at tini'sdocumentation, it has been possible for a couple of years to use tiny without changing the Docker images, by using the --init command-line option to docker run. When doing that, docker injects tiny in the image and runs the entrypoint through it (it still works if one added tini explicitly in the image).

Here's an interesting discussion about whether to explicitly use tini in docker images or use the docker command-line option: krallin/tini#81 . For me the best argument was that, at the time, a lot of users were likely to run a docker version without this feature. Over two years later, this may not be a big problem anymore.

So have you considered a documentation update instead of adding tini in the image? As it is, we would need to do the same for other images in this repo. If we instead document to use the --init option in the README, it would cover all images.

P.S: Node.js suggests using either --init or to include tini in images, rather than having node as init process:
https://github.com/nodejs/docker-node/blob/master/docs/BestPractices.md#handling-kernel-signals

[tom-shan]

I agree with you. Adding --init is actually a simpler way.

[marcdumais-work]

@tom-shan would you care to submit an updated PR that documents the use of the --init docker run option? e.g. in the repo's README.md?

[tom-shan]

I just search the entire repo and modify these commands of docker run.

[marcdumais-work]

I just search the entire repo and modify these commands of docker run

Up-to you if you think a mention of the reason why --init is needed would also be good to add.

[tom-shan]

Aha!

[marcdumais-work]

LGTM, thanks for the contribution @tom-shan