sientia-dataops-opc-ingestor/tests/unit/connection/test_servers.py

from unittest.mock import AsyncMock, MagicMock

import pytest

from ingestor.connection.servers import CONNECTORS, OPC_SERVERS, ServerConfigResolver

CONNECTOR = {
    'connector_id': 1,
    'type': 'opc_ua',
    'status': 'Active',
    'name': 'kepserver',
    'url': 'opc.tcp://kepserver:49320',
    'server_uri': 'urn:kepserver',
    'use_security': True,
}
OPC_SERVER = {
    'id': '1',
    'server_name': 'kepserver',
    'url': 'opc.tcp://legacy:49320',
    'uri': 'urn:legacy',
    'cert_path': '/app/certs/cert.pem',
}


def make_resolver(connector=None, opc_server=None, pooled=None, ttl_s=60.0):
    pool = MagicMock()
    pool.config_for = MagicMock(return_value=pooled)
    mongo = MagicMock()

    async def find_one(collection, _filters, _metadata):
        return {CONNECTORS: connector, OPC_SERVERS: opc_server}[collection]

    mongo.find_one = AsyncMock(side_effect=find_one)
    return ServerConfigResolver(pool, mongo, MagicMock(), ttl_s=ttl_s)


@pytest.mark.asyncio
async def test_command_connection_overrides_every_other_source():
    resolver = make_resolver(connector=CONNECTOR)

    cfg = await resolver.resolve('1', {'url': 'opc.tcp://h:1', 'server_uri': 'urn:h'})

    assert cfg == {'url': 'opc.tcp://h:1', 'server_uri': 'urn:h', 'use_security': False}
    resolver.mongo.find_one.assert_not_awaited()


@pytest.mark.asyncio
async def test_live_pooled_connection_wins_over_mongo():
    """Writes reuse exactly the settings the read path opened the connection with."""
    pooled = {'url': 'opc.tcp://read:1', 'server_uri': 'urn:read', 'use_security': True}
    resolver = make_resolver(connector=CONNECTOR, pooled=pooled)

    assert await resolver.resolve('1', {}) == pooled
    resolver.pool.config_for.assert_called_once_with('1')
    resolver.mongo.find_one.assert_not_awaited()


@pytest.mark.asyncio
async def test_tag_database_connector_first():
    resolver = make_resolver(connector=CONNECTOR, opc_server=OPC_SERVER)

    cfg = await resolver.resolve('1', {})

    assert cfg == {
        'url': 'opc.tcp://kepserver:49320',
        'server_uri': 'urn:kepserver',
        'use_security': True,
    }
    collection, filters, _ = resolver.mongo.find_one.await_args_list[0].args
    assert collection == CONNECTORS
    # connector_id is an int in the tag database; the command carries a string.
    assert filters == {'connector_id': {'$in': ['1', 1]}, 'type': 'opc_ua', 'status': 'Active'}


@pytest.mark.asyncio
async def test_opc_servers_fallback_without_tag_database():
    resolver = make_resolver(connector=None, opc_server=OPC_SERVER)

    cfg = await resolver.resolve('1', {})

    # Same rule as the orchestrator's read slot: a cert_path means security.
    assert cfg == {
        'url': 'opc.tcp://legacy:49320',
        'server_uri': 'urn:legacy',
        'use_security': True,
    }
    collection, filters, _ = resolver.mongo.find_one.await_args_list[1].args
    assert collection == OPC_SERVERS
    assert filters == {'id': {'$in': ['1', 1]}}


@pytest.mark.asyncio
async def test_opc_server_without_cert_path_is_insecure():
    resolver = make_resolver(opc_server={**OPC_SERVER, 'cert_path': ''})

    assert (await resolver.resolve('1', {}))['use_security'] is False


@pytest.mark.asyncio
async def test_non_numeric_server_id_is_looked_up_as_is():
    resolver = make_resolver(opc_server={**OPC_SERVER, 'id': 'kep-a'})

    await resolver.resolve('kep-a', {})

    _, filters, _ = resolver.mongo.find_one.await_args_list[0].args
    assert filters['connector_id'] == {'$in': ['kep-a']}


@pytest.mark.asyncio
async def test_unknown_server_is_cached_briefly():
    resolver = make_resolver(ttl_s=60.0)
    resolver.missing_ttl_s = 10.0
    resolver.clock = MagicMock()
    resolver.clock.elapsed.side_effect = [0.0, 5.0, 11.0]

    assert await resolver.resolve('9', {}) is None
    assert await resolver.resolve('9', {}) is None  # within missing_ttl_s: no lookup
    assert await resolver.resolve('9', {}) is None  # expired: looked up again
    assert resolver.mongo.find_one.await_count == 4  # 2 lookups (connectors + opc-servers)
    assert resolver.logger.warning.call_count == 2


@pytest.mark.asyncio
async def test_documents_without_url_are_ignored():
    resolver = make_resolver(connector={**CONNECTOR, 'url': ''}, opc_server=OPC_SERVER)

    assert (await resolver.resolve('1', {}))['url'] == 'opc.tcp://legacy:49320'


@pytest.mark.asyncio
async def test_lookups_are_cached_for_the_ttl():
    resolver = make_resolver(connector=CONNECTOR, ttl_s=60.0)
    resolver.clock = MagicMock()
    resolver.clock.elapsed.side_effect = [0.0, 30.0, 61.0]

    first = await resolver.resolve('1', {})
    first['url'] = 'mutated by the caller'
    second = await resolver.resolve('1', {})  # within the TTL: cached, and a copy
    await resolver.resolve('1', {})  # expired: looked up again

    assert second['url'] == 'opc.tcp://kepserver:49320'
    assert resolver.mongo.find_one.await_count == 2


@pytest.mark.asyncio
async def test_mongo_errors_propagate_to_the_caller():
    resolver = make_resolver()
    resolver.mongo.find_one = AsyncMock(side_effect=RuntimeError('mongo down'))

    with pytest.raises(RuntimeError, match='mongo down'):
        await resolver.resolve('1', {})