Support ConfiguredGraphFactory configuration in JanusGraph docker

[eanton86]

Hello, JanusGraph maintainers!
I'm working on a JanusGraph setup managed by ConfiguredGraphFactory (documentation). I'm using an usual JanusGraph docker image and found that there is no straight way to make it work using current options (mounted configuration aside).
Basically, we need two configuration files to set up: gremlin-server.yml and janusgraph.properties. There are no problems to customize janusgraph.properties. We can either use JANUS_PROPS_TEMPLATE variable to pick up some configuration template or provide any janusgraph.* variables, or use both.
The problem is with gremlin-server.yml. It requires many modifications, but we don't have the same template variable for it. Using of gremlinserver.* variables doesn't help much, because of how those properties are replaced in gremlin-server.yml, e.g. with current scripts we can not replace this line

graph: /etc/opt/janusgraph/janusgraph.properties

to

ConfigurationManagementGraph: /etc/opt/janusgraph/janusgraph.properties

We can make it work better by doing the following:

1. The main thing - let's apply JANUS_PROPS_TEMPLATE for gremlin-server.yml as well. There are gremlin templates in distribution already that correspond to options of JANUS_PROPS_TEMPLATE (e.g. gremlin-server-cql-es.yml). Only changes in docker-endpoint.sh required.
2. So we can pass in JANUS_PROPS_TEMPLATE, let's say, : cql-configurationgraph to apply gremlin-server-cql-configurationgraph.yml along with janusgraph-cql-configurationgraph.properties. These files are already there, but have different names and locations:

conf\gremlin-server\gremlin-server-configuration.yaml
conf\janusgraph-cql-configurationgraph.properties

So need to move to common folder (gremlin-server) and rename to follow the pattern.
3. Optionally add docker-compose-cql-configurationgraph.yml to make it ready as a whole, so people won't follow the hard way I did.

If my proposal is eligible I can come up with a pull request. What do people think?

[farodin91]

There is already a pr request. I have completely forgot the pr JanusGraph/janusgraph-docker#55.

I will try get the pr out as quick as possible.

[eanton86]

Thanks for pointing out this pr. I will try the new configuration options.