dd sqlalchemy connection metrics for celery tasks

grab the worker app name and task name rather than the web host and
endpoint. also add a fallback for if we're not in a web request or a
celery task. I think that'll probably happen when we use alembic, or if
we do things from within flask shell

app/__init__.py

@@ -4,7 +4,8 @@ import random
 import string
 import uuid
 
-from flask import _request_ctx_stack, request, g, jsonify, make_response
+from celery import current_task
+from flask import _request_ctx_stack, request, g, jsonify, make_response, current_app, has_request_context
 from flask_sqlalchemy import SQLAlchemy as _SQLAlchemy
 from flask_marshmallow import Marshmallow
 from flask_migrate import Migrate
@@ -367,12 +368,33 @@ def setup_sqlalchemy_events(app):
             # this will overwrite any previous checkout_at timestamp
             connection_record.info['checkout_at'] = time.monotonic()
 
-            # checkin runs after the request is already torn down so we'll need to capture request info earlier
+            # checkin runs after the request is already torn down so we'll need to capture request info earlier.
-            connection_record.info['request_data'] = {
+            # checkout runs when the connection is first used, ie: when we first make a query, so within the request or
-                'method': request.method,
+            # task
-                'host': request.host,
+
-                'url_rule': request.url_rule.rule if request.url_rule else 'No endpoint'
+            # web requests
-            }
+            if has_request_context():
+                connection_record.info['request_data'] = {
+                    'method': request.method,
+                    'host': request.host,
+                    'url_rule': request.url_rule.rule if request.url_rule else 'No endpoint'
+                }
+            # celery apps
+            elif current_task:
+                print(current_task)
+                connection_record.info['request_data'] = {
+                    'method': 'celery',
+                    'host': current_app.config['NOTIFY_APP_NAME'],  # worker name
+                    'url_rule': current_task.name,  # task name
+                }
+            # anything else. migrations possibly.
+            else:
+                current_app.logger.warning('Checked out sqlalchemy connection from outside of request/task')
+                connection_record.info['request_data'] = {
+                    'method': 'unknown',
+                    'host': 'unknown',
+                    'url_rule': 'unknown',
+                }
 
         @event.listens_for(db.engine, 'checkin')
         def checkin(dbapi_connection, connection_record):

app/celery/celery.py

@@ -20,8 +20,8 @@ def log_on_worker_shutdown(sender, signal, pid, exitcode, **kwargs):
 
 
 def make_task(app):
-    SQS_APPLY_ASYNC_DURATION = Histogram(
+    SQS_APPLY_ASYNC_DURATION_SECONDS = Histogram(
-        'sqs_apply_async_duration',
+        'sqs_apply_async_duration_seconds',
         'Time taken to put task on queue',
         ['task_name']
     )
@@ -59,7 +59,7 @@ def make_task(app):
             if has_request_context() and hasattr(request, 'request_id'):
                 kwargs['request_id'] = request.request_id
 
-            with SQS_APPLY_ASYNC_DURATION.labels(self.name).time():
+            with SQS_APPLY_ASYNC_DURATION_SECONDS.labels(self.name).time():
                 return super().apply_async(args, kwargs, task_id, producer, link, link_error, **options)
 
     return NotifyTask