chore(gerrit): put the gerrit configuration in one place and generate repo URLs templates

Signed-off-by: Raito Bezarius <raito@lix.systems>

buildbot_nix/__init__.py

@@ -93,6 +93,20 @@ class GerritProject:
     # Private SSH key path to access Gerrit API
     private_sshkey_path: str
 
+@dataclass
+class GerritConfig:
+    # Gerrit server domain
+    domain: str
+    port: int
+    username: str
+
+    @property
+    def repourl_template(self) -> str:
+        """
+        Returns the prefix to build a repourl using that gerrit configuration.
+        """
+        return 'ssh://{self.username}@{self.domain}:{self.port}/'
+
 class BuildTrigger(steps.BuildStep):
     def __init__(
         self,
@@ -430,8 +444,8 @@ class NixBuildCommand(buildstep.ShellMixin, steps.BuildStep):
 
 
 def nix_eval_config(
+    gerrit_config: GerritConfig,
     project: GerritProject,
-    gerrit_private_key: str,
     worker_names: list[str],
     supported_systems: list[str],
     eval_lock: util.MasterLock,
@@ -445,11 +459,11 @@ def nix_eval_config(
     # check out the source
     factory.addStep(
         steps.Gerrit(
-            repourl="ssh://buildbot@gerrit.lix.systems:2022/lix",
+            repourl=f'{gerrit_config.repourl_template}/{project.name}',
             mode="full",
             retry=[60, 60],
             timeout=3600,
-            sshPrivateKey=gerrit_private_key
+            sshPrivateKey=project.private_sshkey_path
         ),
     )
     # use one gcroots directory per worker. this should be scoped to the largest unique resource
@@ -619,6 +633,7 @@ def read_secret_file(secret_name: str) -> str:
 
 def config_for_project(
     config: dict[str, Any],
+    gerrit_config: GerritConfig,
     project: GerritProject,
     worker_names: list[str],
     nix_supported_systems: list[str],
@@ -674,8 +689,8 @@ def config_for_project(
             # Since all workers run on the same machine, we only assign one of them to do the evaluation.
             # This should prevent exessive memory usage.
             nix_eval_config(
+                gerrit_config,
                 project,
-                gerrit_private_key,
                 [ f"{w}-other" for w in worker_names ],
                 supported_systems=nix_supported_systems,
                 worker_count=nix_eval_worker_count,
@@ -764,6 +779,9 @@ class GerritNixConfigurator(ConfiguratorBase):
         self.gerrit_user = gerrit_user
         self.gerrit_port = gerrit_port
         self.gerrit_sshkey_path = gerrit_sshkey_path
+        self.gerrit_config = GerritConfig(domain=self.gerrit_server,
+                                          username=self.gerrit_user,
+                                          port=self.gerrit_port)
         self.projects = projects
 
         self.nix_workers_secret_name = nix_workers_secret_name
@@ -806,6 +824,7 @@ class GerritNixConfigurator(ConfiguratorBase):
         for project in self.projects:
             config_for_project(
                 config,
+                self.gerrit_config,
                 GerritProject(name=project, private_sshkey_path=self.gerrit_sshkey_path),
                 worker_names,
                 self.nix_supported_systems,