HUB_HOST and HUB_PORT to handle hub and nodes

[diemol]

This PR has the following objectives:

• Introduce HUB_HOST and HUB_PORT as a replacement to deprecate HUB_PORT_4444_TCP_ADDR and HUB_PORT_4444_TCP_ADDR.

  • In the entry scripts HUB_HOST and HUB_PORT will map to HUB_PORT_4444_TCP_ADDR and HUB_PORT_4444_TCP_ADDR, and when people use --link with the proposed container name in the examples selenium-hub:hub, it will continue to work.
  • HUB_PORT_4444_TCP_ADDR and HUB_PORT_4444_TCP_ADDR won't be mentioned anymore in the docs, so ideally people will migrate to this new env vars gradually.
  • If a user has the hub with the default 4444 port, then only HUB_HOST would be needed, since HUB_PORT is defaulting to 4444. The user is also able to overwrite HUB_PORT in case the hub is listening to a different port.

• Improving the README showing a "docker network" way to start the grid and a simple docker-compose example, with the intention that users tend to use these ones more than the --link option.

Credits to @SpencerMalone and @RubyTester since most of the content comes from their work and ideas in #136 and #133.

@ddavison, could you please have a look? Let me know if something doesn't look straightforward to you.

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[diemol]

We should squash and merge the PR when the review is complete, the commit history is a bit messy.

[ddavison]

all in all, looks great. just those questions there

[ddavison]

confused about a couple of things, why do you check

"if $HUB_HOST isn't empty, set port to 4444"

also, i see 4 variables...

HUB_HOST, HUB_PORT, HUB_HOST_PARAM, HUB_PORT_PARAM.

what's the differences between these? can';t we consolidate? make things a little simpler?

[diemol]

No, no... There are only 3 variables: HUB_HOST, HUB_PORT and HUB_PORT_PARAM.

What I tried to do is to check first if HUB_HOST was set, if so then use HUB_PORT_PARAM as a placeholder for port 4444 (assuming that the user started the hub with port 4444).

Therefore they only will need to set HUB_HOST and the default port will be 4444. And in case they started the hub with a different port, then HUB_PORT would be set and HUB_PORT_PARAM takes its value.

It could be simplified by doing something like:

if [ ! -z "$HUB_HOST" ] && [ ! -z "$HUB_PORT" ]; then
  echo "Connecting to the Hub using the host ${HUB_HOST} and port ${HUB_PORT}"
  HUB_PORT_4444_TCP_ADDR=${HUB_HOST}
  HUB_PORT_4444_TCP_PORT=${HUB_PORT}
fi

So the user will need to set both variables always. I just thought it could be nicer when the user only needs to set HUB_HOST since in most of the cases people will use 4444 for hub.

What do you think?

[ddavison]

if this is ready to merge @diemol and you're comfortable with it, i'm comfortable with it. you can pull the trigger

[diemol]

Cool, thanks for reviewing @ddavison!
I'll merge tomorrow and prepare a release.