Add debug logging for decision tasks (#498)

* feat: add --verbose option to `taskgraph decision`

* feat(optimize): add more info to task replacement debug logging

Author: jcristau

.taskcluster.yml

@@ -264,6 +264,7 @@ tasks:
                                     ln -s /builds/worker/artifacts artifacts &&
                                     pip3 install --user --break-system-packages . &&
                                     taskgraph decision
+                                    --verbose
                                     --pushlog-id='0'
                                     --pushdate='0'
                                     --project='${project}'

src/taskgraph/decision.py

@@ -74,6 +74,8 @@ def taskgraph_decision(options, parameters=None):
      * generating a set of artifacts to memorialize the graph
      * calling TaskCluster APIs to create the graph
     """
+    if options.get("verbose"):
+        logging.root.setLevel(logging.DEBUG)
 
     parameters = parameters or (
         lambda graph_config: get_decision_parameters(graph_config, options)

src/taskgraph/main.py

@@ -697,6 +697,9 @@ def image_digest(args):
     "--tasks-for", required=True, help="the tasks_for value used to generate this task"
 )
 @argument("--try-task-config-file", help="path to try task configuration file")
+@argument(
+    "--verbose", "-v", action="store_true", help="include debug-level logging output"
+)
 def decision(options):
     from taskgraph.decision import taskgraph_decision
 

src/taskgraph/optimize/base.py

@@ -316,7 +316,7 @@ def replace_tasks(
                 removed_tasks.add(label)
             else:
                 logger.debug(
-                    f"replace_tasks: {label} replaced by optimization strategy"
+                    f"replace_tasks: {label} replaced with {repl} by optimization strategy"
                 )
                 label_to_taskid[label] = repl
                 replaced.add(label)