Allow centralized configuration and document it

[bnjbvr]

It'd be great if we could just have a single configuration file or a single directory containing configuration files with all the example configuration files. I think that if the projects gets away from Docker, it does make sense to stop using env variables as the unique way to define configuration variables, and it would make it simpler to use this project if we had a centralized place with all the possible configuration values.

[Phyks]

Sure, this is definitely something desirable. Docker seems quite convenient, especially the Docker compose stuff, I simply don't use it.

The setup/run scripts are more oriented towards demo/dev at the moment.

Still, it's interesting to keep in mind that micro services can run on different servers. My current setup is:

• viewer and indexer on my main web server, publicly accessible
• crawlers on a raspberry pi at home, accessible only from my LAN, as it handles my passwords

[Phyks]

Another useful feature on this might be to embed doc of each micro service inside the micro service itself, based on ideas from selfapi/swagger and similar to what janitor does.

[Phyks]

By the way, there are two types of config and environment variables:

• The local ones, to configure the microservice itself (host, port, misc options such as imap credentials).
• The global ones, to connect the microservices together (INDEXER_URL etc).

In an ideal world, I think the routing should be handled by something such as infotuyo, hence the global configuration would not exist. But local configuration should remain local for each microservice, in my opinion.