fix(ingest): use branch info when cloning git repos

metadata-ingestion/src/datahub/configuration/github.py

@@ -12,7 +12,7 @@ class GitHubReference(ConfigModel):
     )
     branch: str = Field(
         "main",
-        description="Branch on which your files live by default. Typically main or master.",
+        description="Branch on which your files live by default. Typically main or master. This can also be a commit hash.",
     )
     base_url: str = Field(
         "https://github.com",
@@ -73,3 +73,15 @@ def auto_infer_from_repo(cls, v: Optional[str], values: Dict[str, Any]) -> str:
         if v is None:
             return f"git@github.com:{values.get('repo')}"
         return v
+
+    @property
+    def branch_for_clone(self) -> Optional[str]:
+        # If branch was manually set, we should use it. Otherwise return None.
+        # We do this because we want to use the default branch unless they override it.
+        # While our default for branch is "main", they could be using "master" or something else.
+        # It's ok if the URLs we generate are slightly incorrect, but changing branch to be
+        # required would be a breaking change.
+
+        if "branch" in self.__fields_set__:
+            return self.branch
+        return None

metadata-ingestion/src/datahub/ingestion/source/git/git_import.py

@@ -17,7 +17,9 @@ def __init__(self, tmp_dir: str, skip_known_host_verification: bool = True):
         self.skip_known_host_verification = skip_known_host_verification
         self.last_repo_cloned: Optional[git.Repo] = None
 
-    def clone(self, ssh_key: Optional[SecretStr], repo_url: str) -> Path:
+    def clone(
+        self, ssh_key: Optional[SecretStr], repo_url: str, branch: Optional[str] = None
+    ) -> Path:
         unique_dir = str(uuid4())
         keys_dir = f"{self.tmp_dir}/{unique_dir}/keys"
         checkout_dir = f"{self.tmp_dir}/{unique_dir}/checkout"
@@ -58,6 +60,11 @@ def clone(self, ssh_key: Optional[SecretStr], repo_url: str) -> Path:
             env=dict(GIT_SSH_COMMAND=git_ssh_cmd),
         )
         logger.info("✅ Cloning complete!")
+
+        if branch is not None:
+            logger.info(f"Checking out branch {branch}")
+            self.last_repo_cloned.git.checkout(branch)
+
         return pathlib.Path(checkout_dir)
 
     def get_last_repo_cloned(self) -> Optional[git.Repo]:

metadata-ingestion/src/datahub/ingestion/source/looker/lookml_source.py

@@ -1434,6 +1434,7 @@ def get_workunits_internal(self) -> Iterable[MetadataWorkUnit]:
                 checkout_dir = git_clone.clone(
                     ssh_key=self.source_config.github_info.deploy_key,
                     repo_url=self.source_config.github_info.repo_ssh_locator,
+                    branch=self.source_config.github_info.branch_for_clone,
                 )
                 self.reporter.git_clone_latency = datetime.now() - start_time
                 self.source_config.base_folder = checkout_dir.resolve()
@@ -1463,6 +1464,7 @@ def get_workunits_internal(self) -> Iterable[MetadataWorkUnit]:
                                 )
                             ),
                             repo_url=p_ref.repo_ssh_locator,
+                            branch=p_ref.branch_for_clone,
                         )
 
                         p_ref = p_checkout_dir.resolve()

metadata-ingestion/tests/integration/git/test_git_clone.py

@@ -1,31 +1,50 @@
 import os
 
+import pytest
 from pydantic import SecretStr
 
+from datahub.configuration.github import GitHubInfo
 from datahub.ingestion.source.git.git_import import GitClone
 
+LOOKML_TEST_SSH_KEY = os.environ.get("DATAHUB_LOOKML_GIT_TEST_SSH_KEY")
 
-def test_git_clone(pytestconfig, tmp_path):
+
+@pytest.mark.skipif(
+    LOOKML_TEST_SSH_KEY is None,
+    reason="DATAHUB_LOOKML_GIT_TEST_SSH_KEY env variable is not configured",
+)
+def test_git_clone(tmp_path):
     git_clone = GitClone(str(tmp_path))
-    secret_env_variable = "DATAHUB_LOOKML_GIT_TEST_SSH_KEY"
-    if os.environ.get(secret_env_variable) is not None:
-        secret_key = SecretStr(os.environ.get(secret_env_variable))  # type: ignore
-        checkout_dir = git_clone.clone(
-            ssh_key=secret_key,
-            repo_url="git@github.com:acryldata/long-tail-companions-looker",
-        )
-        assert os.path.exists(checkout_dir)
-        assert set(os.listdir(checkout_dir)) == set(
-            [
-                ".datahub",
-                "models",
-                "README.md",
-                ".github",
-                ".git",
-                "views",
-            ]
-        )
-    else:
-        print(
-            "Skipping test as env variable DATAHUB_LOOKML_GIT_TEST_SSH_KEY is not configured"
-        )
+    secret_key = SecretStr(LOOKML_TEST_SSH_KEY) if LOOKML_TEST_SSH_KEY else None
+
+    checkout_dir = git_clone.clone(
+        ssh_key=secret_key,
+        repo_url="git@github.com:acryldata/long-tail-companions-looker",
+        branch="d380a2b777ec6f4653626f39c68dba85893faa74",
+    )
+    assert os.path.exists(checkout_dir)
+    assert set(os.listdir(checkout_dir)) == set(
+        [
+            ".datahub",
+            "models",
+            "README.md",
+            ".github",
+            ".git",
+            "views",
+            "manifest_lock.lkml",
+            "manifest.lkml",
+        ]
+    )
+
+
+def test_github_branch():
+    config = GitHubInfo(
+        repo="owner/repo",
+    )
+    assert config.branch_for_clone is None
+
+    config = GitHubInfo(
+        repo="owner/repo",
+        branch="main",
+    )
+    assert config.branch_for_clone == "main"