[FEATURE] Add Provider for domain_code

[margau]

This PR adds a provider for domain_code, which allows to display the domain of the gateway inside meshviewer etc.
Example usage: https://map.ffm.freifunk.net/#!/de/map/aaff04000802

[rubo77]

Sieht gut aus, ist einfacher als wenn man bei jedem Gateway einzeln die Domain in den alias.json eintragen muss

[TobleMiner]

Overall good. Necessary changes are small, thus I'll implement them myself.

[TobleMiner]

Why do we put that in the local_env? Isn't that a global setting? Think this should go here:

mesh-announce/respondd.py

Line 103 in 2635b00

get_handler(get_providers(args.directory), batadv_ifaces, batadv_mesh_ipv4_overrides, {'mesh_ipv4': args.mesh_ipv4})

[margau]

Okay, I probably misunderstood how the local_env is used exactly.

[TobleMiner]

Well, local_env is intended for values that can change per request. In contrast the global environment - which was hard to spot since it is only passed as a function argument - contains values that are fixed, no matter what interface a request is received on.

[TobleMiner]

There should be a reasonable default for this value. I'd suggest setting it to 'default' when -n is not specified.

[margau]

Do we need a default? If nothing is set, there should be no domain transmitted (as it is now)?

[TobleMiner]

Hm, ok. That is a side effect of having a None value in there then. I would have expected it to break due to an exception somewhere in handler processing when a handler returns None.

I'll add an is_enabled method to data sources so they can signal wether they should be called or not. This seems a lot clearer to me than handling None values all the time.

[TobleMiner]

I'd suggest this solution: https://github.com/ffnord/mesh-announce/compare/master...TobleMiner:feature-domain-name?expand=1

Please test and leave feedback.

[margau]

The "is_enabled" flag seems to be broken at the moment:

  File "/opt/mesh-announce/providers/__init__.py", line 145, in call  
    if source.is_enabled(env):  
AttributeError: 'Source' object has no attribute 'is_enabled'```

Thanks for the improvements!

[TobleMiner]

Ah, my fault. Need to proxy the call through the Source object. Should be fixed now. Please try again.

[margau]

Test without and with the Gateway-Option was successfull, everything okay from my side.

[TobleMiner]

Just tested it as well. Seems to work fine.

[TobleMiner]

Merged, thanks for the PR!

[herbetom]

Is there an option to set the domain_code without starting multiple instances (in a multi-domain Setup)?

From the README.md this seems to be the way to start mesh-announce for a multi-domain site: respondd.py -d /opt/mesh-announce/providers -i meshvpn-one -i br-one -i bat-one -b bat-one -i meshvpn-two -i br-two -i bat-two -b bat-two -i meshvpn-three -i br-three -i bat-three -b bat-three

As far as i can see, it is only possible to specify a single -n <domain code>?

[TobleMiner]

Hm, right. That is kind of required. However currently it is not possible.

It's actually an option that would probably need to be attached to the -i option again. Please make a separate issue for that. Makes it easier to track it.