cli.py: Add artifact delete command

This command provides a --no-prune option because or a large cache, pruning
can be an expensive operation. If a developer wishes to quicky rebuild an artifact,
they may consider using this option.

4 files changed, 160 insertions, 1 deletions

diff --git a/buildstream/_frontend/cli.py b/buildstream/_frontend/cli.py
index 02ca52e85..d8c46ce0c 100644
--- a/buildstream/_frontend/cli.py
+++ b/buildstream/_frontend/cli.py
@@ -1106,6 +1106,20 @@ def artifact_log(app, artifacts):
                         click.echo_via_pager(data)
 
 
+###################################################################
+#                     Artifact Delete Command                     #
+###################################################################
+@artifact.command(name='delete', short_help="Remove artifacts from the local cache")
+@click.option('--no-prune', 'no_prune', default=False, is_flag=True,
+              help="Do not prune the local cache of unreachable refs")
+@click.argument('artifacts', type=click.Path(), nargs=-1)
+@click.pass_obj
+def artifact_delete(app, artifacts, no_prune):
+    """Remove artifacts from the local cache"""
+    with app.initialized():
+        app.stream.artifact_delete(artifacts, no_prune)
+
+
 ##################################################################
 #                      DEPRECATED Commands                       #
 ##################################################################
diff --git a/buildstream/_stream.py b/buildstream/_stream.py
index b0fce3817..5c880427c 100644
--- a/buildstream/_stream.py
+++ b/buildstream/_stream.py
@@ -30,11 +30,12 @@ from contextlib import contextmanager, suppress
 from fnmatch import fnmatch
 
 from ._artifactelement import verify_artifact_ref
-from ._exceptions import StreamError, ImplError, BstError, ArtifactElementError, set_last_task_error
+from ._exceptions import StreamError, ImplError, BstError, ArtifactElementError, CASCacheError, set_last_task_error
 from ._message import Message, MessageType
 from ._scheduler import Scheduler, SchedStatus, TrackQueue, FetchQueue, BuildQueue, PullQueue, PushQueue
 from ._pipeline import Pipeline, PipelineSelection
 from ._profile import Topics, profile_start, profile_end
+from .types import _KeyStrength
 from . import utils, _yaml, _site
 from . import Scope, Consistency
 
@@ -520,6 +521,45 @@ class Stream():
 
         return logsdirs
 
+    # artifact_delete()
+    #
+    # Remove artifacts from the local cache
+    #
+    # Args:
+    #    targets (str): Targets to remove
+    #    no_prune (bool): Whether to prune the unreachable refs, default False
+    #
+    def artifact_delete(self, targets, no_prune):
+        # Return list of Element and/or ArtifactElement objects
+        target_objects = self.load_selection(targets, selection=PipelineSelection.NONE, load_refs=True)
+
+        # Some of the targets may refer to the same key, so first obtain a
+        # set of the refs to be removed.
+        remove_refs = set()
+        for obj in target_objects:
+            for key_strength in [_KeyStrength.STRONG, _KeyStrength.WEAK]:
+                key = obj._get_cache_key(strength=key_strength)
+                remove_refs.add(obj.get_artifact_name(key=key))
+
+        ref_removed = False
+        for ref in remove_refs:
+            try:
+                self._artifacts.remove(ref, defer_prune=True)
+            except CASCacheError as e:
+                self._message(MessageType.WARN, "{}".format(e))
+                continue
+
+            self._message(MessageType.INFO, "Removed: {}".format(ref))
+            ref_removed = True
+
+        # Prune the artifact cache
+        if ref_removed and not no_prune:
+            with self._context.timed_activity("Pruning artifact cache"):
+                self._artifacts.prune()
+
+        if not ref_removed:
+            self._message(MessageType.INFO, "No artifacts were removed")
+
     # source_checkout()
     #
     # Checkout sources of the target element to the specified location
diff --git a/tests/frontend/artifact.py b/tests/frontend/artifact.py
index c8301c529..3c3203d8a 100644
--- a/tests/frontend/artifact.py
+++ b/tests/frontend/artifact.py
@@ -22,6 +22,7 @@ import os
 import pytest
 
 from buildstream.plugintestutils import cli
+from tests.testutils import create_artifact_share
 
 
 # Project directory
@@ -62,3 +63,106 @@ def test_artifact_log(cli, datafiles):
     assert result.exit_code == 0
     # The artifact is cached under both a strong key and a weak key
     assert (log + log) == result.output
+
+
+# Test that we can delete the artifact of the element which corresponds
+# to the current project state
+@pytest.mark.datafiles(DATA_DIR)
+def test_artifact_delete_element(cli, tmpdir, datafiles):
+    project = os.path.join(datafiles.dirname, datafiles.basename)
+    element = 'target.bst'
+
+    # Build the element and ensure it's cached
+    result = cli.run(project=project, args=['build', element])
+    result.assert_success()
+    assert cli.get_element_state(project, element) == 'cached'
+
+    result = cli.run(project=project, args=['artifact', 'delete', element])
+    result.assert_success()
+    assert cli.get_element_state(project, element) != 'cached'
+
+
+# Test that we can delete an artifact by specifying its ref.
+@pytest.mark.datafiles(DATA_DIR)
+def test_artifact_delete_artifact(cli, tmpdir, datafiles):
+    project = os.path.join(datafiles.dirname, datafiles.basename)
+    element = 'target.bst'
+
+    # Configure a local cache
+    local_cache = os.path.join(str(tmpdir), 'artifacts')
+    cli.configure({'cachedir': local_cache})
+
+    # First build an element so that we can find its artifact
+    result = cli.run(project=project, args=['build', element])
+    result.assert_success()
+
+    # Obtain the artifact ref
+    cache_key = cli.get_element_key(project, element)
+    artifact = os.path.join('test', os.path.splitext(element)[0], cache_key)
+
+    # Explicitly check that the ARTIFACT exists in the cache
+    assert os.path.exists(os.path.join(local_cache, 'cas', 'refs', 'heads', artifact))
+
+    # Delete the artifact
+    result = cli.run(project=project, args=['artifact', 'delete', artifact])
+    result.assert_success()
+
+    # Check that the ARTIFACT is no longer in the cache
+    assert not os.path.exists(os.path.join(local_cache, 'cas', 'refs', 'heads', artifact))
+
+
+# Test the `bst artifact delete` command with multiple, different arguments.
+@pytest.mark.datafiles(DATA_DIR)
+def test_artifact_delete_element_and_artifact(cli, tmpdir, datafiles):
+    project = os.path.join(datafiles.dirname, datafiles.basename)
+    element = 'target.bst'
+    dep = 'compose-all.bst'
+
+    # Configure a local cache
+    local_cache = os.path.join(str(tmpdir), 'artifacts')
+    cli.configure({'cachedir': local_cache})
+
+    # First build an element so that we can find its artifact
+    result = cli.run(project=project, args=['build', element])
+    result.assert_success()
+    assert cli.get_element_state(project, element) == 'cached'
+    assert cli.get_element_state(project, dep) == 'cached'
+
+    # Obtain the artifact ref
+    cache_key = cli.get_element_key(project, element)
+    artifact = os.path.join('test', os.path.splitext(element)[0], cache_key)
+
+    # Explicitly check that the ARTIFACT exists in the cache
+    assert os.path.exists(os.path.join(local_cache, 'cas', 'refs', 'heads', artifact))
+
+    # Delete the artifact
+    result = cli.run(project=project, args=['artifact', 'delete', artifact, dep])
+    result.assert_success()
+
+    # Check that the ARTIFACT is no longer in the cache
+    assert not os.path.exists(os.path.join(local_cache, 'cas', 'refs', 'heads', artifact))
+
+    # Check that the dependency ELEMENT is no longer cached
+    assert cli.get_element_state(project, dep) != 'cached'
+
+
+# Test that we receive the appropriate stderr when we try to delete an artifact
+# that is not present in the cache.
+@pytest.mark.datafiles(DATA_DIR)
+def test_artifact_delete_unbuilt_artifact(cli, tmpdir, datafiles):
+    project = os.path.join(datafiles.dirname, datafiles.basename)
+    element = 'target.bst'
+
+    # delete it, just in case it's there
+    _ = cli.run(project=project, args=['artifact', 'delete', element])
+
+    # Ensure the element is not cached
+    assert cli.get_element_state(project, element) != 'cached'
+
+    # Now try and remove it again (now we know its not there)
+    result = cli.run(project=project, args=['artifact', 'delete', element])
+
+    cache_key = cli.get_element_key(project, element)
+    artifact = os.path.join('test', os.path.splitext(element)[0], cache_key)
+    expected_err = "WARNING Could not find ref '{}'".format(artifact)
+    assert expected_err in result.stderr
diff --git a/tests/frontend/completions.py b/tests/frontend/completions.py
index 1f29fdae6..7810a06d5 100644
--- a/tests/frontend/completions.py
+++ b/tests/frontend/completions.py
@@ -57,6 +57,7 @@ SOURCE_COMMANDS = [
 
 ARTIFACT_COMMANDS = [
     'checkout ',
+    'delete ',
     'push ',
     'pull ',
     'log ',