cli: Add artifact log command

1 files changed, 59 insertions, 0 deletions

diff --git a/buildstream/_frontend/cli.py b/buildstream/_frontend/cli.py
index 67958385c..84133f608 100644
--- a/buildstream/_frontend/cli.py
+++ b/buildstream/_frontend/cli.py
@@ -1,6 +1,8 @@
 import os
 import sys
+from contextlib import ExitStack
 from fnmatch import fnmatch
+from tempfile import TemporaryDirectory
 
 import click
 from .. import _yaml
@@ -976,3 +978,60 @@ def _classify_artifacts(names, cas, project_directory):
 def artifact():
     """Manipulate cached artifacts"""
     pass
+
+
+################################################################
+#                     Artifact Log Command                     #
+################################################################
+@artifact.command(name='log', short_help="Show logs of an artifact")
+@click.argument('artifacts', type=click.Path(), nargs=-1)
+@click.pass_obj
+def artifact_log(app, artifacts):
+    """Show logs of all artifacts"""
+    from .._exceptions import CASError
+    from .._message import MessageType
+    from .._pipeline import PipelineSelection
+    from ..storage._casbaseddirectory import CasBasedDirectory
+
+    with ExitStack() as stack:
+        stack.enter_context(app.initialized())
+        cache = app.context.artifactcache
+
+        elements, artifacts = _classify_artifacts(artifacts, cache.cas,
+                                                  app.project.directory)
+
+        vdirs = []
+        extractdirs = []
+        if artifacts:
+            for ref in artifacts:
+                try:
+                    cache_id = cache.cas.resolve_ref(ref, update_mtime=True)
+                    vdir = CasBasedDirectory(cache.cas, cache_id)
+                    vdirs.append(vdir)
+                except CASError as e:
+                    app._message(MessageType.WARN, "Artifact {} is not cached".format(ref), detail=str(e))
+                    continue
+        if elements:
+            elements = app.stream.load_selection(elements, selection=PipelineSelection.NONE)
+            for element in elements:
+                if not element._cached():
+                    app._message(MessageType.WARN, "Element {} is not cached".format(element))
+                    continue
+                ref = cache.get_artifact_fullname(element, element._get_cache_key())
+                cache_id = cache.cas.resolve_ref(ref, update_mtime=True)
+                vdir = CasBasedDirectory(cache.cas, cache_id)
+                vdirs.append(vdir)
+
+        for vdir in vdirs:
+            # NOTE: If reading the logs feels unresponsive, here would be a good place to provide progress information.
+            logsdir = vdir.descend(["logs"])
+            td = stack.enter_context(TemporaryDirectory())
+            logsdir.export_files(td, can_link=True)
+            extractdirs.append(td)
+
+        for extractdir in extractdirs:
+            for log in (os.path.join(extractdir, log) for log in os.listdir(extractdir)):
+                # NOTE: Should click gain the ability to pass files to the pager this can be optimised.
+                with open(log) as f:
+                    data = f.read()
+                    click.echo_via_pager(data)