[GCU] Add pfcwd interval config tests (#4811)

tests/generic_config_updater/test_pfcwd_interval.py

@@ -0,0 +1,157 @@
+import logging
+import json
+import pytest
+
+from tests.common.helpers.assertions import pytest_assert
+from tests.common.utilities import wait_until
+from tests.generic_config_updater.gu_utils import apply_patch, expect_op_success, expect_res_success, expect_op_failure
+from tests.generic_config_updater.gu_utils import generate_tmpfile, delete_tmpfile
+from tests.generic_config_updater.gu_utils import create_checkpoint, delete_checkpoint, rollback_or_reload
+
+pytestmark = [
+    pytest.mark.asic('mellanox')
+]
+
+logger = logging.getLogger(__name__)
+
+READ_FLEXCOUNTER_DB_TIMEOUT = 480
+READ_FLEXCOUNTER_DB_INTERVAL = 20
+
+
+@pytest.fixture(scope="module")
+def ensure_dut_readiness(duthost):
+    """
+    Setup/teardown fixture for pfcwd interval config update tst
+
+    Args:
+        duthost: DUT host object
+    """
+    create_checkpoint(duthost)
+
+    yield
+
+    try:
+        logger.info("Rolled back to original  checkpoint")
+        rollback_or_reload(duthost)
+    finally:
+        delete_checkpoint(duthost)
+
+
+def ensure_application_of_updated_config(duthost, value):
+    """
+    Ensures application of the JSON patch config update by verifying field value presence in FLEX COUNTER DB
+
+    Args:
+        duthost: DUT host object
+        value: expected value of POLL_INTERVAL
+    """
+    def _confirm_value_in_flex_counter_db():
+        poll_interval = duthost.shell('sonic-db-cli PFC_WD_DB hget FLEX_COUNTER_GROUP_TABLE:PFC_WD POLL_INTERVAL')["stdout"]
+        return value == poll_interval
+
+    pytest_assert(
+        wait_until(READ_FLEXCOUNTER_DB_TIMEOUT, READ_FLEXCOUNTER_DB_INTERVAL, 0, _confirm_value_in_flex_counter_db),
+        "FLEX COUNTER DB does not properly reflect newly POLL_INTERVAL expected value: {}".format(value)
+    )
+
+
+def prepare_pfcwd_interval_config(duthost, value):
+    """
+    Prepares config db by setting pfcwd poll interval to specified value. If value is empty string, delete the current entry. 
+
+    Args:
+        duthost: DUT host object
+        value: poll interval value to be set
+    """
+
+    logger.info("Setting configdb entry pfcwd poll interval to value: {}".format(value))
+
+    if value:
+        cmd = "pfcwd interval {}".format(value)
+    else:
+        cmd = "sonic-db-cli CONFIG_DB del \PFC_WD\GLOBAL\POLL_INTERVAL"
+
+    duthost.shell(cmd)
+
+
+def get_detection_restoration_times(duthost):
+    """
+    Returns detection_time, restoration_time for an interface. Poll_interval must be greater than both in order to be valid
+    
+    Args:
+        duthost: DUT host object
+    """
+
+    pfcwd_config = duthost.shell("show pfcwd config")
+    pytest_assert(not pfcwd_config['rc'], "Unable to read pfcwd config")
+
+    for line in pfcwd_config['stdout_lines']:
+        if line.startswith('Ethernet'):
+            interface = line.split()[0] # Since line starts with Ethernet, we can safely use 0 index
+
+            cmd = "sonic-db-cli CONFIG_DB hget \"PFC_WD|{}\" \"detection_time\" ".format(interface)
+            output = duthost.shell(cmd, module_ignore_errors=True)
+            pytest_assert(not output['rc'], "Unable to read detection time")
+            detection_time = output["stdout"]
+
+            cmd = "sonic-db-cli CONFIG_DB hget \"PFC_WD|{}\" \"restoration_time\" ".format(interface)
+            output = duthost.shell(cmd, module_ignore_errors=True)
+            pytest_assert(not output['rc'], "Unable to read restoration time")
+            restoration_time = output["stdout"]
+
+            return int(detection_time), int(restoration_time)
+
+    pytest_assert(True, "Failed to read detection_time and/or restoration time")
+
+
+def get_new_interval(duthost, is_valid):
+    """
+    Returns new interval value for pfcwd poll interval, based on the operation being performed
+
+    Args:
+        duthost: DUT host object
+        is_valid: if is_valid is true, return a valid new interval. Config update should succeed. If is_valid is false, return an invalid new interval. Config update should fail.
+    """
+
+    detection_time, restoration_time = get_detection_restoration_times(duthost)
+    if is_valid:
+        return max(detection_time, restoration_time) - 10
+    else:
+        return min(detection_time, restoration_time) + 10
+
+
+@pytest.mark.parametrize("operation", ["add", "replace"])
+@pytest.mark.parametrize("field_pre_status", ["existing", "nonexistent"])
+@pytest.mark.parametrize("is_valid_config_update", [True, False])
+def test_pfcwd_interval_config_updates(duthost, ensure_dut_readiness, operation, field_pre_status, is_valid_config_update):
+    new_interval = get_new_interval(duthost, is_valid_config_update)
+
+    operation_to_new_value_map = {"add": "{}".format(new_interval), "replace": "{}".format(new_interval), "remove": ""}
+    detection_time, restoration_time = get_detection_restoration_times(duthost)
+    pre_status = max(detection_time, restoration_time)
+    field_pre_status_to_value_map = {"existing": "{}".format(pre_status), "nonexistent": ""}
+
+    prepare_pfcwd_interval_config(duthost, field_pre_status_to_value_map[field_pre_status]) 
+
+    tmpfile = generate_tmpfile(duthost)
+    logger.info("tmpfile {} created for json patch of pfcwd poll interval and operation: {}".format(tmpfile, operation))
+    value = operation_to_new_value_map[operation]
+    logger.info("value to be added to json patch: {}".format(value))
+
+    json_patch = [
+        {
+            "op": "{}".format(operation), 
+            "path": "/PFC_WD/GLOBAL/POLL_INTERVAL", 
+            "value": "{}".format(value)
+        }]
+
+    try:
+        output = apply_patch(duthost, json_data=json_patch, dest_file=tmpfile)
+
+        if is_valid_config_update:
+            expect_op_success(duthost, output)
+            ensure_application_of_updated_config(duthost, value)
+        else:
+            expect_op_failure(output)
+    finally:
+        delete_tmpfile(duthost, tmpfile)