Ensure that --metrics-port is specified when --prometheus is used when running ursula.

Added/Cleaned up some tests

nucypher/cli/commands/ursula.py

@@ -384,6 +384,11 @@ def run(general_config, character_options, config_file, interactive, dry_run, me
 
     prometheus_config: 'PrometheusMetricsConfig' = None
     if prometheus:
+        # ensure metrics port is provided
+        if not metrics_port:
+            raise click.BadOptionUsage(option_name='metrics-port',
+                                       message='--metrics-port is required when using --prometheus')
+
         # Locally scoped to prevent import without prometheus explicitly installed
         from nucypher.utilities.prometheus.metrics import PrometheusMetricsConfig
         prometheus_config = PrometheusMetricsConfig(port=metrics_port,

nucypher/utilities/prometheus/metrics.py

@@ -57,9 +57,15 @@ class PrometheusMetricsConfig:
     def __init__(self,
                  port: int,
                  metrics_prefix: str,
-                 listen_address: str,
+                 listen_address: str = '',  # default to localhost ip
                  collection_interval: int = 10,
                  start_now: bool = False):
+
+        if not port:
+            raise ValueError('port must be provided')
+        if not metrics_prefix:
+            raise ValueError('metrics prefix must be provided')
+
         self.port = port
         self.metrics_prefix = metrics_prefix
         self.listen_address = listen_address

tests/acceptance/cli/ursula/test_run_ursula.py

@@ -20,6 +20,7 @@ from unittest import mock
 
 import pytest
 import pytest_twisted as pt
+from click import BadOptionUsage
 from twisted.internet import threads
 
 from nucypher import utilities
@@ -72,6 +73,26 @@ def test_ursula_rest_host_determination(click_runner, mocker):
     assert isinstance(result.exception, UnknownIPAddress)
 
 
+@pt.inlineCallbacks
+def test_ursula_run_with_prometheus_but_no_metrics_port(click_runner):
+    args = ('ursula', 'run',  # Stat Ursula Command
+            '--debug',  # Display log output; Do not attach console
+            '--federated-only',  # Operating Mode
+            '--dev',  # Run in development mode (ephemeral node)
+            '--dry-run',  # Disable twisted reactor in subprocess
+            '--lonely',  # Do not load seednodes
+            '--prometheus'  # Specify collection of prometheus metrics
+            )
+
+    result = yield threads.deferToThread(click_runner.invoke,
+                                         nucypher_cli, args,
+                                         catch_exceptions=False)
+
+    assert result.exit_code != 0
+    expected_error = f"Error: --metrics-port is required when using --prometheus"
+    assert expected_error in result.output
+
+
 @pt.inlineCallbacks
 def test_run_lone_federated_default_development_ursula(click_runner):
     deploy_port = select_test_port()

tests/unit/test_prometheus.py

@@ -44,27 +44,37 @@ TEST_PREFIX = 'test_prefix'
 
 
 def test_prometheus_metrics_config():
-    listen_address = '111.111.111.111'
     port = 2020
+
+    # no port
+    with pytest.raises(ValueError):
+        PrometheusMetricsConfig(port=None, metrics_prefix=TEST_PREFIX)
+
+    # no prefix
+    with pytest.raises(ValueError):
+        PrometheusMetricsConfig(port=port, metrics_prefix=None)
+
     prometheus_config = PrometheusMetricsConfig(port=port,
-                                                metrics_prefix=TEST_PREFIX,
-                                                listen_address=listen_address)
+                                                metrics_prefix=TEST_PREFIX)
 
     assert prometheus_config.port == 2020
     assert prometheus_config.metrics_prefix == TEST_PREFIX
-    assert prometheus_config.listen_address == listen_address
+    assert prometheus_config.listen_address == ''
 
     # defaults
     assert prometheus_config.collection_interval == 10
     assert not prometheus_config.start_now
+    assert prometheus_config.listen_address == ''
 
     # non-defaults
     collection_interval = 5
+    listen_address = '111.111.111.111'
     prometheus_config = PrometheusMetricsConfig(port=port,
                                                 metrics_prefix=TEST_PREFIX,
                                                 listen_address=listen_address,
                                                 collection_interval=collection_interval,
                                                 start_now=True)
+    assert prometheus_config.listen_address == listen_address
     assert prometheus_config.collection_interval == collection_interval
     assert prometheus_config.start_now