disabling datastore feature parameter

[riccardomodanese]

Signed-off-by: riccardomodanese riccardo.modanese@eurotech.com
Added a feature to disable completely the datastore feature from the broker.
The idea is to allow Kapua to start and run without any exception in a deploy without any datastore.
This is controlled by an environment variable:

• KAPUA_DATASTORE_DISABLE if true the broker doesn't create any datastore related object (and so doesn't try to connect to it)

Related Issue
none

Description of the solution adopted
none

Screenshots
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Any side note on the changes made
In this PR there's also some updates to the code originally merged with #2947. Specifically:

• isAvailableService() has been renamed to isServiceEnabled()
• isAvailableProperty() has been renamed to isPropertyEnabled()
• isServiceEnabled() has been moved from AbstractKapuaConfigurableService to AbstractKapuaService
• When reading configuration for a disabled service, now KapuaServiceDisabledException is thrown instead of silently return null

[riccardomodanese]

@lorthirk should we add a similar feature in the console and rest api also?

[lorthirk]

This means that <!-- BEGIN DATASTORE PERSISTENCE --> and <!-- END DATASTORE PERSISTENCE --> comments have now special semantics. Are we sure we want to do this? I suspect that someone could not understand this by just looking at the file. Maybe we should at least document this somewhere?

[codecov]

Codecov Report

Merging #2963 into develop will decrease coverage by 0.08%.
The diff coverage is 15.68%.

@@              Coverage Diff              @@
##             develop    #2963      +/-   ##
=============================================
- Coverage      56.19%   56.11%   -0.09%     
- Complexity      2591     2594       +3     
=============================================
  Files           1061     1062       +1     
  Lines          23002    23042      +40     
  Branches        2064     2064              
=============================================
+ Hits           12926    12930       +4     
- Misses          9123     9140      +17     
- Partials         953      972      +19     

Impacted Files	Coverage Δ	Complexity Δ
...ervice/internal/KapuaServiceDisabledException.java	0.00% <0.00%> (ø)	0.00 <0.00> (?)
...store/internal/ChannelInfoRegistryServiceImpl.java	73.19% <0.00%> (-9.37%)	12.00 <7.00> (+1.00)	⬇️
...astore/internal/ClientInfoRegistryServiceImpl.java	72.63% <0.00%> (-9.52%)	12.00 <7.00> (+1.00)	⬇️
...ce/datastore/internal/MessageStoreServiceImpl.java	52.63% <0.00%> (-0.56%)	11.00 <1.00> (+1.00)	⬇️
...astore/internal/MetricInfoRegistryServiceImpl.java	73.19% <0.00%> (-9.37%)	12.00 <7.00> (+1.00)	⬇️
...onfiguration/AbstractKapuaConfigurableService.java	76.87% <30.00%> (-1.22%)	0.00 <0.00> (ø)
...commons/service/internal/AbstractKapuaService.java	75.00% <100.00%> (+2.27%)	0.00 <0.00> (ø)
...c/main/java/org/eclipse/kapua/KapuaErrorCodes.java	100.00% <100.00%> (ø)	1.00 <0.00> (ø)
...atastore/internal/setting/DatastoreSettingKey.java	100.00% <100.00%> (ø)	3.00 <0.00> (ø)
...obDeviceManagementOperationManagerServiceImpl.java	73.17% <0.00%> (-6.10%)	13.00% <0.00%> (-1.00%)
... and 7 more