Move ArtifactError to exceptions.py

This avoids cyclic imports between element.py and artifactcache.py.

5 files changed, 22 insertions, 23 deletions

diff --git a/buildstream/_artifactcache/__init__.py b/buildstream/_artifactcache/__init__.py
index 76ee871f4..638575f5a 100644
--- a/buildstream/_artifactcache/__init__.py
+++ b/buildstream/_artifactcache/__init__.py
@@ -18,7 +18,7 @@
 #  Authors:
 #        Tristan Van Berkom <tristan.vanberkom@codethink.co.uk>
 
-from .artifactcache import ArtifactCache, ArtifactError
+from .artifactcache import ArtifactCache
 
 # Entry points for our local ostree-push implementation
 from .pushreceive import receive_main
diff --git a/buildstream/_artifactcache/artifactcache.py b/buildstream/_artifactcache/artifactcache.py
index 0693515bf..9435321c8 100644
--- a/buildstream/_artifactcache/artifactcache.py
+++ b/buildstream/_artifactcache/artifactcache.py
@@ -22,19 +22,14 @@ import os
 import tempfile
 
 from .. import _ostree, utils
-from ..exceptions import _BstError
+from ..exceptions import _ArtifactError
 from .._ostree import OSTreeError
 
 from .pushreceive import push as push_artifact
 from .pushreceive import PushException
 
 
-# For users of this file, they must expect (except) it.
-class ArtifactError(_BstError):
-    pass
-
-
-def buildref(element):
+def buildref(element, key):
     project = element.get_project()
     key = element._get_cache_key()
 
@@ -109,7 +104,7 @@ class ArtifactCache():
     #     element (Element): The Element to extract
     #
     # Raises:
-    #     ArtifactError: In cases there was an OSError, or if the artifact
+    #     _ArtifactError: In cases there was an OSError, or if the artifact
     #                    did not exist.
     #
     # Returns: path to extracted artifact
@@ -125,7 +120,7 @@ class ArtifactCache():
         # resolve ref to checksum
         rev = _ostree.checksum(self.repo, ref)
         if not rev:
-            raise ArtifactError("Artifact missing for {}".format(ref))
+            raise _ArtifactError("Artifact missing for {}".format(ref))
 
         os.makedirs(self.extractdir, exist_ok=True)
         with tempfile.TemporaryDirectory(prefix='tmp', dir=self.extractdir) as tmpdir:
@@ -144,8 +139,8 @@ class ArtifactCache():
                 # If rename fails with these errors, another process beat
                 # us to it so just ignore.
                 if e.errno not in [os.errno.ENOTEMPTY, os.errno.EEXIST]:
-                    raise ArtifactError("Failed to extract artifact for ref '{}': {}"
-                                        .format(ref, e)) from e
+                    raise _ArtifactError("Failed to extract artifact for ref '{}': {}"
+                                         .format(ref, e)) from e
 
         return dest
 
@@ -186,15 +181,15 @@ class ArtifactCache():
         elif self.remote is not None:
             remote = self.remote
         else:
-            raise ArtifactError("Attempt to pull artifact without any pull URL")
+            raise _ArtifactError("Attempt to pull artifact without any pull URL")
 
         ref = buildref(element)
         try:
             _ostree.fetch(self.repo, remote=remote,
                           ref=ref, progress=progress)
         except OSTreeError as e:
-            raise ArtifactError("Failed to pull artifact for element {}: {}"
-                                .format(element.name, e)) from e
+            raise _ArtifactError("Failed to pull artifact for element {}: {}"
+                                 .format(element.name, e)) from e
 
     # can_push():
     #
@@ -217,11 +212,11 @@ class ArtifactCache():
     #           and no updated was required
     #
     # Raises:
-    #   ArtifactError if there was an error
+    #   _ArtifactError if there was an error
     def push(self, element):
 
         if self.context.artifact_push is None:
-            raise ArtifactError("Attempt to push artifact without any push URL")
+            raise _ArtifactError("Attempt to push artifact without any push URL")
 
         ref = buildref(element)
         if self.context.artifact_push.startswith("/"):
@@ -252,6 +247,6 @@ class ArtifactCache():
                                                self.context.artifact_push_port,
                                                ref, output_file)
                     except PushException as e:
-                        raise ArtifactError("Failed to push artifact {}: {}".format(ref, e)) from e
+                        raise _ArtifactError("Failed to push artifact {}: {}".format(ref, e)) from e
 
                 return pushed
diff --git a/buildstream/element.py b/buildstream/element.py
index db2fd44b1..dbdae352c 100644
--- a/buildstream/element.py
+++ b/buildstream/element.py
@@ -33,10 +33,9 @@ import shutil
 from . import _yaml
 from ._yaml import CompositePolicy
 from ._variables import Variables
-from .exceptions import _BstError
+from .exceptions import _BstError, _ArtifactError
 from . import LoadError, LoadErrorReason, ElementError, ImplError
 from ._sandboxbwrap import SandboxBwrap
-from ._artifactcache import ArtifactError
 from . import Sandbox, SandboxFlags
 from . import Plugin, Consistency
 from . import utils
@@ -940,7 +939,7 @@ class Element(Plugin):
             display_key = self._get_display_key()
             self.info("Downloaded artifact {}".format(display_key))
             downloaded = True
-        except ArtifactError:
+        except _ArtifactError:
             # Just return false, so that the frontend knows that
             # the artifact was not downloaded
             #
diff --git a/buildstream/exceptions.py b/buildstream/exceptions.py
index b28a9c22a..039551c16 100644
--- a/buildstream/exceptions.py
+++ b/buildstream/exceptions.py
@@ -128,3 +128,7 @@ class ProgramNotFoundError(_BstError):
     bubblewrap is installed for it to work.
     """
     pass
+
+
+class _ArtifactError(_BstError):
+    pass
diff --git a/tests/artifactcache/basics.py b/tests/artifactcache/basics.py
index c7661820c..6fc8a8b7c 100644
--- a/tests/artifactcache/basics.py
+++ b/tests/artifactcache/basics.py
@@ -3,7 +3,8 @@ import pytest
 import tempfile
 
 from buildstream import Context, Project
-from buildstream._artifactcache import ArtifactCache, ArtifactError
+from buildstream.exceptions import _ArtifactError
+from buildstream._artifactcache import ArtifactCache
 from buildstream._pipeline import Pipeline
 
 DATA_DIR = os.path.join(
@@ -30,7 +31,7 @@ def test_empty_contains(pipeline):
 
 # Test that we get an ArtifactError when trying to extract a nonexistent artifact
 def test_empty_extract(pipeline):
-    with pytest.raises(ArtifactError) as exc:
+    with pytest.raises(_ArtifactError) as exc:
         pipeline.artifacts.extract(pipeline.target)