context: Move scheduler actions to an Enum

Also add helpers for the cli to be able to represent 'FastEnum' directly

4 files changed, 38 insertions, 6 deletions

diff --git a/src/buildstream/_context.py b/src/buildstream/_context.py
index c18f9426d..4d68ef222 100644
--- a/src/buildstream/_context.py
+++ b/src/buildstream/_context.py
@@ -29,6 +29,7 @@ from ._platform import Platform
 from ._artifactcache import ArtifactCache
 from ._sourcecache import SourceCache
 from ._cas import CASCache, CASQuota, CASCacheUsage
+from .types import _SchedulerErrorAction
 from ._workspaces import Workspaces, WorkspaceProjectCache
 from .node import Node
 from .sandbox import SandboxRemote
@@ -323,8 +324,7 @@ class Context():
             'on-error', 'fetchers', 'builders',
             'pushers', 'network-retries'
         ])
-        self.sched_error_action = _node_get_option_str(
-            scheduler, 'on-error', ['continue', 'quit', 'terminate'])
+        self.sched_error_action = scheduler.get_enum('on-error', _SchedulerErrorAction)
         self.sched_fetchers = scheduler.get_int('fetchers')
         self.sched_builders = scheduler.get_int('builders')
         self.sched_pushers = scheduler.get_int('pushers')
diff --git a/src/buildstream/_frontend/app.py b/src/buildstream/_frontend/app.py
index 76d3b8dde..379ed4b7f 100644
--- a/src/buildstream/_frontend/app.py
+++ b/src/buildstream/_frontend/app.py
@@ -37,6 +37,7 @@ from .._exceptions import BstError, StreamError, LoadError, LoadErrorReason, App
 from .._message import Message, MessageType, unconditional_messages
 from .._stream import Stream
 from .._versions import BST_FORMAT_VERSION
+from ..types import _SchedulerErrorAction
 from .. import node
 
 # Import frontend assets
@@ -597,11 +598,11 @@ class App():
         # Handle non interactive mode setting of what to do when a job fails.
         if not self._interactive_failures:
 
-            if self.context.sched_error_action == 'terminate':
+            if self.context.sched_error_action == _SchedulerErrorAction.TERMINATE:
                 self.stream.terminate()
-            elif self.context.sched_error_action == 'quit':
+            elif self.context.sched_error_action == _SchedulerErrorAction.QUIT:
                 self.stream.quit()
-            elif self.context.sched_error_action == 'continue':
+            elif self.context.sched_error_action == _SchedulerErrorAction.CONTINUE:
                 pass
             return
 
diff --git a/src/buildstream/_frontend/cli.py b/src/buildstream/_frontend/cli.py
index 12b9439cf..5de02918f 100644
--- a/src/buildstream/_frontend/cli.py
+++ b/src/buildstream/_frontend/cli.py
@@ -10,10 +10,25 @@ from .. import _yaml
 from .._exceptions import BstError, LoadError, AppError
 from .._versions import BST_FORMAT_VERSION
 from .complete import main_bashcomplete, complete_path, CompleteUnhandled
+from ..types import _SchedulerErrorAction
 from ..utils import _get_compression, UtilError
 
 
 ##################################################################
+#              Helper classes and methods for Click              #
+##################################################################
+
+class FastEnumType(click.Choice):
+
+    def __init__(self, enum):
+        self._enum = enum
+        super().__init__(enum.values())
+
+    def convert(self, value, param, ctx):
+        return self._enum(super().convert(value, param, ctx))
+
+
+##################################################################
 #            Override of click's main entry point                #
 ##################################################################
 
@@ -234,7 +249,7 @@ def print_version(ctx, param, value):
               type=click.Path(file_okay=False, readable=True),
               help="Project directory (default: current directory)")
 @click.option('--on-error', default=None,
-              type=click.Choice(['continue', 'quit', 'terminate']),
+              type=FastEnumType(_SchedulerErrorAction),
               help="What to do when an error is encountered")
 @click.option('--fetchers', type=click.INT, default=None,
               help="Maximum simultaneous download tasks")
diff --git a/src/buildstream/types.py b/src/buildstream/types.py
index ff4a3cc57..08e2b0d08 100644
--- a/src/buildstream/types.py
+++ b/src/buildstream/types.py
@@ -192,3 +192,19 @@ class _KeyStrength(FastEnum):
     # Includes names of direct build dependencies but does not include
     # cache keys of dependencies.
     WEAK = 2
+
+
+# _SchedulerErrorAction()
+#
+# Actions the scheduler can take on error
+#
+class _SchedulerErrorAction(FastEnum):
+
+    # Continue building the rest of the tree
+    CONTINUE = "continue"
+
+    # finish ongoing work and quit
+    QUIT = "quit"
+
+    # Abort immediately
+    TERMINATE = "terminate"