Create gRPC service to be used by the CLI

[adombeck]

The current state of #782 adds the gRPC methods used by the CLI to the NSS service. They don't belong there, so this PR adds a new gRPC service which provides methods intended for use by the CLI.

UDENG-6492

[3v1n0]

I wouldn't call it CLI but I rather something like Manager or something similar, as this something that we could ideally expose later in other tools (such as gcc), and we can include here every operation that is about the management of authd (or its users) itself, despite the UI that is used for that.

[adombeck]

Ok, what about this structure then:

service UsersService {
  rpc ListUsers(Empty) returns (Users);
  rpc DisableUser(DisableUserRequest) returns (Empty);
  rpc EnableUser(EnableUserRequest) returns (Empty);
}

message User {
  string name = 1;
  uint32 uid = 2;
  uint32 gid = 3;
  string gecos = 4;
  string homedir = 5;
  string shell = 6;
}

message Users {
  repeated User users = 1;
}

service GroupsService {
  rpc ListGroups(Empty) returns (Groups);
}

message Group {
  string name = 1;
  uint32 gid = 2;
  repeated string members = 3;
}

message Groups {
  repeated Group groups = 1;
}

[3v1n0]

Yeah, that's better, we can still keep it more generic, but I feel this is enough, and in case we can add another one if needed

[adombeck]

I implemented something similar to that

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 92.20779% with 6 lines in your changes missing coverage. Please review.

Project coverage is 85.37%. Comparing base (fbb5642) to head (69dc5ec).
Report is 23 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/services/user/user.go	92.53%	5 Missing ⚠️
internal/services/permissions.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #855      +/-   ##
==========================================
- Coverage   85.37%   85.37%   -0.01%     
==========================================
  Files          80       80              
  Lines        5532     5518      -14     
  Branches      109      109              
==========================================
- Hits         4723     4711      -12     
+ Misses        754      752       -2     
  Partials       55       55              

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[denisonbarbosa]

Some suggestions that I think will make the changes better (I didn't add the same comment on every single crate of the module, but some apply to all three)

[adombeck]

Converting to draft until I fixed the tests

[3v1n0]

Rename this function too please

[adombeck]

done

[3v1n0]

Rename this function too please

[adombeck]

done

[3v1n0]

And this

[adombeck]

done

[denisonbarbosa]

Looks good to me. Nice work! Once @3v1n0 is also happy, feel free to merge.

[shiv-tyagi]

Thanks @adombeck for the awesome work.