feat(build): Output metadata file when calling build command

Author: Ishirui

src/dda/build/artifacts/binaries/core_agent.py

@@ -100,14 +100,12 @@ def name(self) -> str:
         return "core-agent"
 
     @override
-    def build(self, app: Application, *args: Any, **kwargs: Any) -> None:
-        from dda.utils.fs import Path
-
+    def build(self, app: Application, output: Path, *args: Any, **kwargs: Any) -> None:
         # TODO: Build rtloader first if needed
         # TODO: Make this build in a devenv ? Or at least add a flag
         app.tools.go.build(
             "github.com/DataDog/datadog-agent/cmd/agent",
-            output=Path("./bin/agent"),
+            output=output,
             build_tags=self.get_build_tags(),
             gcflags=self.get_gcflags(),
             ldflags=self.get_ldflags(app),

src/dda/cli/build/bin/core_agent/__init__.py

@@ -5,17 +5,49 @@
 
 from typing import TYPE_CHECKING
 
+import click
+
+from dda.build.metadata.digests import ArtifactDigest, DigestType
 from dda.cli.base import dynamic_command, pass_app
+from dda.utils.fs import Path
 
 if TYPE_CHECKING:
     from dda.cli.application import Application
 
+DEFAULT_OUTPUT_PLACEHOLDER = Path("./bin/agent/canonical_filename")
+
 
 @dynamic_command(short_help="Build the `core-agent` binary.")
+@click.option(
+    "--output",
+    "-o",
+    type=click.Path(file_okay=True, dir_okay=False, exists=False, writable=True),
+    default=DEFAULT_OUTPUT_PLACEHOLDER,
+    help="""
+The path on which to create the binary.
+Defaults to bin/agent/canonical_filename - the canonical filename of the built artifact.
+This filename contains some metadata about the built artifact, e.g. commit hash, build timestamp, etc.
+    """,
+)
 @pass_app
-def cmd(app: Application) -> None:
+def cmd(app: Application, output: Path) -> None:
+    import shutil
+
     from dda.build.artifacts.binaries.core_agent import CoreAgent
+    from dda.utils.fs import temp_file
 
     artifact = CoreAgent()
     app.display_waiting("Building the `core-agent` binary...")
-    artifact.build(app)
+    with temp_file() as tf:
+        artifact.build(app, output=tf)
+        digest = ArtifactDigest(value=tf.hexdigest(), type=DigestType.FILE_SHA256)
+
+        metadata = artifact.compute_metadata(app, digest)
+
+        # Special case: if output is the default value, use the canonical filename from the metadata
+        if output == DEFAULT_OUTPUT_PLACEHOLDER:
+            output = Path("./bin/") / metadata.get_canonical_filename()
+
+        output.parent.mkdir(parents=True, exist_ok=True)
+        shutil.move(tf, output)
+    metadata.to_file(output.with_suffix(".json"))