feat(gateway): OpcConnectionPool (per-server, reuse, idle-evict)

tests/unit/connection/test_pool.py

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+from unittest.mock import AsyncMock, MagicMock, patch
+
+import pytest
+
+import ingestor.metrics as metrics
+from ingestor.connection.pool import OpcConnectionPool
+
+
+def make_pool(cert_provider=None):
+    pool = OpcConnectionPool(
+        cert_provider=cert_provider or AsyncMock(),
+        logger=MagicMock(),
+        notification_handler=MagicMock(),
+        metrics_controller=AsyncMock(),
+        metadata={},
+    )
+    pool.emit_metric = AsyncMock()
+    return pool
+
+
+@pytest.mark.asyncio
+async def test_get_reuses_connection_per_server():
+    pool = make_pool()
+    fake_client = AsyncMock()
+    with patch('ingestor.connection.pool.Client', return_value=fake_client):
+        c1 = await pool.get('srv', {'url': 'opc.tcp://h:4840', 'use_security': False})
+        c2 = await pool.get('srv', {'url': 'opc.tcp://h:4840', 'use_security': False})
+
+    assert c1 is c2
+    assert fake_client.connect.await_count == 1
+
+
+@pytest.mark.asyncio
+async def test_get_failure_records_metric_and_raises():
+    pool = make_pool()
+    fake_client = AsyncMock()
+    fake_client.connect.side_effect = RuntimeError('boom')
+    with patch('ingestor.connection.pool.Client', return_value=fake_client):
+        with pytest.raises(RuntimeError):
+            await pool.get('srv', {'url': 'opc.tcp://h:4840', 'use_security': False})
+
+    pool.emit_metric.assert_any_await(
+        metric_object=metrics.OPC_CONNECTIONS_FAILED,
+        tags={'pod_id': pool.pod_id, 'server_name': 'srv'},
+    )
+    assert 'srv' not in pool._connections
+
+    # a later successful get must reconnect (failed attempt was not cached)
+    fake_client2 = AsyncMock()
+    with patch('ingestor.connection.pool.Client', return_value=fake_client2):
+        client = await pool.get('srv', {'url': 'opc.tcp://h:4840', 'use_security': False})
+    assert client is fake_client2
+    assert fake_client2.connect.await_count == 1
+
+
+@pytest.mark.asyncio
+async def test_get_applies_security_when_requested():
+    cert_provider = AsyncMock()
+    cert_provider.fetch.return_value = ('cert.pem', 'key.pem')
+    pool = make_pool(cert_provider=cert_provider)
+    fake_client = AsyncMock()
+    with (
+        patch('ingestor.connection.pool.Client', return_value=fake_client),
+        patch('ingestor.connection.pool.apply_security', new=AsyncMock()) as mock_apply,
+    ):
+        await pool.get(
+            'srv',
+            {'url': 'opc.tcp://h:4840', 'server_uri': 'urn:test', 'use_security': True},
+        )
+
+    cert_provider.fetch.assert_awaited_once()
+    mock_apply.assert_awaited_once_with(fake_client, 'urn:test', 'cert.pem', 'key.pem', None)
+
+
+@pytest.mark.asyncio
+async def test_release_idle_evicts_and_disconnects():
+    pool = make_pool()
+    fake_client = AsyncMock()
+    with patch('ingestor.connection.pool.Client', return_value=fake_client):
+        await pool.get('srv', {'url': 'opc.tcp://h:4840', 'use_security': False})
+
+    client, _ = pool._connections['srv']
+    pool._connections['srv'] = (client, -1000.0)  # force idle
+
+    await pool.release_idle(max_idle_s=0)
+
+    fake_client.disconnect.assert_awaited_once()
+    assert 'srv' not in pool._connections
+
+
+@pytest.mark.asyncio
+async def test_release_idle_keeps_recently_used():
+    pool = make_pool()
+    fake_client = AsyncMock()
+    with patch('ingestor.connection.pool.Client', return_value=fake_client):
+        await pool.get('srv', {'url': 'opc.tcp://h:4840', 'use_security': False})
+
+    await pool.release_idle(max_idle_s=3600)
+
+    fake_client.disconnect.assert_not_awaited()
+    assert 'srv' in pool._connections
+
+
+@pytest.mark.asyncio
+async def test_close_all_disconnects_everything():
+    pool = make_pool()
+    fake_a, fake_b = AsyncMock(), AsyncMock()
+    with patch('ingestor.connection.pool.Client', side_effect=[fake_a, fake_b]):
+        await pool.get('a', {'url': 'opc.tcp://h:4840', 'use_security': False})
+        await pool.get('b', {'url': 'opc.tcp://h:4840', 'use_security': False})
+
+    await pool.close_all()
+
+    fake_a.disconnect.assert_awaited_once()
+    fake_b.disconnect.assert_awaited_once()
+    assert pool._connections == {}
+
+
+@pytest.mark.asyncio
+async def test_release_idle_disconnect_retries_then_gives_up():
+    pool = make_pool()
+    fake_client = AsyncMock()
+    fake_client.disconnect.side_effect = RuntimeError('nope')
+    with patch('ingestor.connection.pool.Client', return_value=fake_client):
+        await pool.get('srv', {'url': 'opc.tcp://h:4840', 'use_security': False})
+
+    client, _ = pool._connections['srv']
+    pool._connections['srv'] = (client, -1000.0)
+
+    await pool.release_idle(max_idle_s=0)
+
+    assert fake_client.disconnect.await_count == 5
+    assert 'srv' not in pool._connections