Use cached testbedInfo and host_vars in inventory in dut selection fixtures (#2811)

What is the motivation for this PR?
pytest_generate_tests dynamically adds enum_* fixtures that select DUTs on which the tests are to be parameterized. In order to select the DUTs on which the tests are to run, we need to get the TestbedInfo and also all variables defined in the inventory file for each DUT. These operations are time consuming - like creating TestbedInfo taking 1-9 seconds, and getting variables from inventory taking 3-5 seconds.

pytest_generate_tests is called for all the tests/fixtures that needs to run in a pytest session. This was adding a long time when trying to execute many tests.

This issue was reported in issue #2790 - pytest_generate_tests in tests/conftest.py takes much more time than before

How did you do it?
To fix this, we need to create the TestbedInfo only once, store it, and then use the stored value in the next execution of pytest_generate_tests, rather than re-creating TestbedInfo. Similary, the variables for all the DUTs in the testbed should be read once from the inventory files, stored, and the re-used in the next execution of pytest_generate_tests.

PR #2789 Added caching capability to store any facts using pickle.
PR #2856 added caching capability for TestbedInfo
PR #2873 added caching capability for variables for DUTs in the inventory files.

We use the cached TestbedInfo and DUT variables in the selection of DUTs in pytest_generate_tests.

How did you verify/test it?
Ran tests that use the dut selection fixtures and validated that the delay is seen only once, and not in every call to pytest_generate_tests.
Validated the execution time reduced significantly when using caching when executing iface_namingmode test cases which have ~30 tests.

Author: sanmalho-git

tests/common/helpers/dut_utils.py

@@ -11,8 +11,8 @@ def is_supervisor_node(inv_files, hostname):
           the inventory, and it is 'supervisor', then return True, else return False. In future, we can change this
           logic if possible to derive it from the DUT.
     """
-    node_type = get_host_visible_vars(inv_files, hostname, variable='type')
-    if node_type and node_type == 'supervisor':
+    dut_vars = get_host_visible_vars(inv_files, hostname)
+    if 'type' in dut_vars and dut_vars['type'] == 'supervisor':
         return True
     return False
 

tests/conftest.py

@@ -204,9 +204,7 @@ def duthost(duthosts, request):
 def rand_one_dut_hostname(request):
     """
     """
-    tbname, testbedinfo = get_tbinfo(request)
-    duts_in_testbed = testbedinfo["duts"]
-    dut_hostnames = generate_params_dut_hostname(duts_in_testbed, tbname)
+    dut_hostnames = generate_params_dut_hostname(request)
     if len(dut_hostnames) > 1:
         dut_hostnames = random.sample(dut_hostnames, 1)
     return dut_hostnames[0]
@@ -226,16 +224,6 @@ def rand_one_dut_lossless_prio(request):
         lossless_prio_list = random.sample(lossless_prio_list, 1)
     return lossless_prio_list[0]
 
-@pytest.fixture(scope="module")
-def rand_one_frontend_dut_hostname(request):
-    """
-    """
-    tbname, testbedinfo = get_tbinfo(request)
-    duts_in_testbed = testbedinfo["duts"]
-    frontend_dut_hostnames = generate_params_frontend_hostname(request, duts_in_testbed, tbname)
-    dut_hostnames = random.sample(frontend_dut_hostnames, 1)
-    return dut_hostnames[0]
-
 @pytest.fixture(scope="module", autouse=True)
 def reset_critical_services_list(duthosts):
     """
@@ -611,28 +599,37 @@ def get_host_data(request, dut):
     return get_host_vars(inv_files, dut)
 
 
-def generate_params_frontend_hostname(request, duts_in_testbed, tbname):
+def generate_params_frontend_hostname(request):
     frontend_duts = []
+    tbname, tbinfo = get_tbinfo(request)
+    duts = tbinfo['duts']
     inv_files = get_inventory_files(request)
-    for dut in duts_in_testbed:
+    for dut in duts:
         if is_frontend_node(inv_files, dut):
             frontend_duts.append(dut)
     assert len(frontend_duts) > 0, \
         "Test selected require at-least one frontend node, " \
-        "none of the DUTs '{}' in testbed '{}' are a supervisor node".format(duts_in_testbed, tbname)
+        "none of the DUTs '{}' in testbed '{}' are a supervisor node".format(duts, tbname)
     return frontend_duts
 
 
-def generate_params_frontend_hostname_rand_per_hwsku(request, duts_in_testbed, tbname):
-    frontend_hosts = generate_params_frontend_hostname(request, duts_in_testbed, tbname)
+def generate_params_hostname_rand_per_hwsku(request, frontend_only=False):
+    tbname, tbinfo = get_tbinfo(request)
+    hosts = tbinfo['duts']
+    if frontend_only:
+        hosts = generate_params_frontend_hostname(request)
     inv_files = get_inventory_files(request)
     # Create a list of hosts per hwsku
     host_hwskus = {}
-    for a_host in frontend_hosts:
-        a_host_hwsku = get_host_visible_vars(inv_files, a_host, variable='hwsku')
-        if not a_host_hwsku:
+    for a_host in hosts:
+        host_vars = get_host_visible_vars(inv_files, a_host)
+        a_host_hwsku = None
+        if 'hwsku' in host_vars:
+            a_host_hwsku = host_vars['hwsku']
+        else:
             # Lets try 'sonic_hwsku' as well
-            a_host_hwsku = get_host_visible_vars(inv_files, a_host, variable='sonic_hwsku')
+            if 'sonic_hwsku' in host_vars:
+                a_host_hwsku = host_vars['sonic_hwsku']
         if a_host_hwsku:
             if a_host_hwsku not in host_hwskus:
                 host_hwskus[a_host_hwsku] = [a_host]
@@ -641,56 +638,65 @@ def generate_params_frontend_hostname_rand_per_hwsku(request, duts_in_testbed, t
         else:
             pytest.fail("Test selected require a node per hwsku, but 'hwsku' for '{}' not defined in the inventory".format(a_host))
 
-    frontend_hosts_per_hwsku = []
+    hosts_per_hwsku = []
     for hosts in host_hwskus.values():
         if len(hosts) == 1:
-            frontend_hosts_per_hwsku.append(hosts[0])
+            hosts_per_hwsku.append(hosts[0])
         else:
-            frontend_hosts_per_hwsku.extend(random.sample(hosts, 1))
+            hosts_per_hwsku.extend(random.sample(hosts, 1))
 
-    return frontend_hosts_per_hwsku
+    return hosts_per_hwsku
 
 
-def generate_params_supervisor_hostname(request, duts_in_testbed, tbname):
-    if len(duts_in_testbed) == 1:
+def generate_params_supervisor_hostname(request):
+    tbname, tbinfo = get_tbinfo(request)
+    duts = tbinfo['duts']
+    if len(duts) == 1:
         # We have a single node - dealing with pizza box, return it
-        return [duts_in_testbed[0]]
+        return [duts[0]]
     inv_files = get_inventory_files(request)
-    for dut in duts_in_testbed:
+    for dut in duts:
         # Expecting only a single supervisor node
         if is_supervisor_node(inv_files, dut):
             return [dut]
     pytest.fail("Test selected require a supervisor node, " +
-                "none of the DUTs '{}' in testbed '{}' are a supervisor node".format(duts_in_testbed, tbname))
-
+                "none of the DUTs '{}' in testbed '{}' are a supervisor node".format(duts, tbname))
 
-def generate_param_asic_index(request, duts_in_testbed, dut_indices, param_type):
-    logging.info("generating {} asic indices for  DUT [{}] in ".format(param_type, dut_indices))
+def generate_param_asic_index(request, dut_indices, param_type):
+    _, tbinfo = get_tbinfo(request)
+    inv_files = get_inventory_files(request)
+    logging.info("generating {} asic indicies for  DUT [{}] in ".format(param_type, dut_indices))
     #if the params are not present treat the device as a single asic device
     asic_index_params = [DEFAULT_ASIC_ID]
 
     for dut_id in dut_indices:
-        dut = duts_in_testbed[dut_id]
-        inv_data = get_host_data(request, dut)
+        dut = tbinfo['duts'][dut_id]
+        inv_data = get_host_visible_vars(inv_files, dut)
         if inv_data is not None:
             if param_type == ASIC_PARAM_TYPE_ALL and ASIC_PARAM_TYPE_ALL in inv_data:
-                asic_index_params = range(int(inv_data[ASIC_PARAM_TYPE_ALL]))
+                if int(inv_data[ASIC_PARAM_TYPE_ALL]) == 1:
+                    asic_index_params = [DEFAULT_ASIC_ID]
+                else:
+                    asic_index_params = range(int(inv_data[ASIC_PARAM_TYPE_ALL]))
             elif param_type == ASIC_PARAM_TYPE_FRONTEND and ASIC_PARAM_TYPE_FRONTEND in inv_data:
                 asic_index_params = inv_data[ASIC_PARAM_TYPE_FRONTEND]
             logging.info("dut_index {} dut name {}  asics params = {}".format(
                 dut_id, dut, asic_index_params))
     return asic_index_params
 
 
-def generate_params_dut_index(duts_in_testbeds, tbname):
-    num_duts = len(duts_in_testbeds)
+def generate_params_dut_index(request):
+    tbname, tbinfo = get_tbinfo(request)
+    num_duts = len(tbinfo['duts'])
     logging.info("Num of duts in testbed '{}' is {}".format(tbname, num_duts))
     return range(num_duts)
 
 
-def generate_params_dut_hostname(duts_in_testbed, tbname):
-    logging.info("DUTs in testbed '{}' are: {}".format(tbname, str(duts_in_testbed)))
-    return duts_in_testbed
+def generate_params_dut_hostname(request):
+    tbname, tbinfo = get_tbinfo(request)
+    duts = tbinfo["duts"]
+    logging.info("DUTs in testbed '{}' are: {}".format(tbname, str(duts)))
+    return duts
 
 
 def generate_port_lists(request, port_scope):
@@ -797,38 +803,41 @@ def generate_priority_lists(request, prio_scope):
     return ret if ret else empty
 
 _frontend_hosts_per_hwsku_per_module = {}
+_hosts_per_hwsku_per_module = {}
 def pytest_generate_tests(metafunc):
     # The topology always has atleast 1 dut
     dut_indices = [0]
-    tbname, testbedinfo = get_tbinfo(metafunc)
-    duts_in_testbed = testbedinfo["duts"]
+    global _frontend_hosts_per_hwsku_per_module, _hosts_per_hwsku_per_module
     # Enumerators ("enum_dut_index", "enum_dut_hostname", "rand_one_dut_hostname") are mutually exclusive
     if "enum_dut_index" in metafunc.fixturenames:
-        dut_indices = generate_params_dut_index(duts_in_testbed, tbname)
+        dut_indices = generate_params_dut_index(metafunc)
         metafunc.parametrize("enum_dut_index", dut_indices, scope="module")
     elif "enum_dut_hostname" in metafunc.fixturenames:
-        dut_hostnames = generate_params_dut_hostname(duts_in_testbed, tbname)
+        dut_hostnames = generate_params_dut_hostname(metafunc)
         metafunc.parametrize("enum_dut_hostname", dut_hostnames, scope="module")
     elif "enum_supervisor_dut_hostname" in metafunc.fixturenames:
-        supervisor_hosts = generate_params_supervisor_hostname(metafunc, duts_in_testbed, tbname)
+        supervisor_hosts = generate_params_supervisor_hostname(metafunc)
         metafunc.parametrize("enum_supervisor_dut_hostname", supervisor_hosts, scope="module")
     elif "enum_frontend_dut_hostname" in metafunc.fixturenames:
-        frontend_hosts = generate_params_frontend_hostname(metafunc, duts_in_testbed, tbname)
+        frontend_hosts = generate_params_frontend_hostname(metafunc)
         metafunc.parametrize("enum_frontend_dut_hostname", frontend_hosts, scope="module")
+    elif "enum_rand_one_per_hwsku_hostname" in metafunc.fixturenames:
+        if metafunc.module not in _hosts_per_hwsku_per_module:
+            hosts_per_hwsku = generate_params_hostname_rand_per_hwsku(metafunc)
+            _hosts_per_hwsku_per_module[metafunc.module] = hosts_per_hwsku
+        hosts = _hosts_per_hwsku_per_module[metafunc.module]
+        metafunc.parametrize("enum_rand_one_per_hwsku_hostname", hosts, scope="module")
     elif "enum_rand_one_per_hwsku_frontend_hostname" in metafunc.fixturenames:
         if metafunc.module not in _frontend_hosts_per_hwsku_per_module:
-            frontend_hosts_per_hwsku = generate_params_frontend_hostname_rand_per_hwsku(metafunc, duts_in_testbed, tbname)
-            _frontend_hosts_per_hwsku_per_module[metafunc.module] = frontend_hosts_per_hwsku
-        frontend_hosts = _frontend_hosts_per_hwsku_per_module[metafunc.module]
-        metafunc.parametrize("enum_rand_one_per_hwsku_frontend_hostname", frontend_hosts, scope="module")
-
+            hosts_per_hwsku = generate_params_hostname_rand_per_hwsku(metafunc, frontend_only=True)
+            _frontend_hosts_per_hwsku_per_module[metafunc.module] = hosts_per_hwsku
+        hosts = _frontend_hosts_per_hwsku_per_module[metafunc.module]
+        metafunc.parametrize("enum_rand_one_per_hwsku_frontend_hostname", hosts, scope="module")
 
     if "enum_asic_index" in metafunc.fixturenames:
-        metafunc.parametrize("enum_asic_index",
-                             generate_param_asic_index(metafunc, duts_in_testbed, dut_indices, ASIC_PARAM_TYPE_ALL))
+        metafunc.parametrize("enum_asic_index", generate_param_asic_index(metafunc, dut_indices, ASIC_PARAM_TYPE_ALL))
     if "enum_frontend_asic_index" in metafunc.fixturenames:
-        metafunc.parametrize("enum_frontend_asic_index",
-                             generate_param_asic_index(metafunc, duts_in_testbed, dut_indices, ASIC_PARAM_TYPE_FRONTEND))
+        metafunc.parametrize("enum_frontend_asic_index",generate_param_asic_index(metafunc, dut_indices, ASIC_PARAM_TYPE_FRONTEND))
 
     if "enum_dut_portname" in metafunc.fixturenames:
         metafunc.parametrize("enum_dut_portname", generate_port_lists(metafunc, "all_ports"))