adding support for docker linking

[nolith]

This patch uses linking environment variables provided by docker and allow you to run hubot and redis in docker. The redis instance has to be aliased as 'brain'

start a persistent redis brain docker run --name hubot_brain -d redis redis-server --appendonly yes

then start your hubot image docker run -d --link hubot_brain:brain your_hubot_image

[MrSaints]

This doesn't seem like a very elegant solution. It's essentially hardcoding a check for BRAIN_PORT_6379_TCP_ADDR under the assumption that the alias / name, and port number exposed is 'brain', and '6379' respectively.

I don't think the script should depend on Docker. It should be agnostic about its deployment.

I think a better approach would be to set the environment variables in a file (using those exposed by Docker), and source it when running a Hubot container. Something like:

export REDIS_URL=redis://${BRAIN_PORT_6379_TCP_ADDR}:${BRAIN_PORT_6379_TCP_PORT}

You could also take advantage of the hosts defined when linking.

e.g.

export REDIS_URL=redis://brain:6379

[nolith]

I agree that it isn't elegant, I don't like the way docker linking works, but you have to consider that this way you can use the standard node:on-build docker image as starting image for your deploy

FROM node:4-onbuild
ENV PORT 8080
EXPOSE 8080

The redis port number it's hardcoded only in the variable name, when you prepare a Dockerfile you must declare which ports are exposed (6379 in case of the official redis image) but when linked it may be exposed under a different port number.

The assumption of the alias it's just an matter of documentation, supporting Docker means declaring which kind of link are supported and which alias should be used.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.