Read environment variables in Constants.py

Instead of using EnsureGlobalVariable,
which is clunky to use from Python.

As a consequence, all caps variables from Constants.py are used directly
and tests/__init__.robot and robot_enhancements.robot are deleted.

+ Rename the CRC global kill switch based on ci-man review.

Change-Id: I10723792475bc83352bf8c3b7f7946ecf885a194
Signed-off-by: Vratko Polak <vrpolak@cisco.com>

8 files changed, 133 insertions, 81 deletions

diff --git a/resources/libraries/python/Constants.py b/resources/libraries/python/Constants.py
index e8209544e8..9606a10fad 100644
--- a/resources/libraries/python/Constants.py
+++ b/resources/libraries/python/Constants.py
@@ -11,7 +11,112 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-"""Constants used in CSIT."""
+"""Constants used in CSIT.
+
+Here, "constant" means a value that keeps its value since initialization.
+However, the value does not need to be hardcoded here,
+some values are affected by environment variables.
+
+TODO: Review env and constant names, make them matching if possible.
+"""
+
+
+import os
+
+
+def get_str_from_env(env_var_names, default_value):
+    """Attempt to read string from environment variable, return that or default.
+
+    If environment variable exists, but is empty (and default is not),
+    empty string is returned.
+
+    Several environment variable names are examined, as CSIT currently supports
+    a mix of naming convensions.
+    Here "several" means there are hardcoded prefixes to try,
+    and env_var_names itself can be single name, or a list or a tuple of names.
+
+    :param env_var_names: Base names of environment variable to attempt to read.
+    :param default_value: Value to return if the env var does not exist.
+    :type env_var_names: str, or list of str, or tuple of str
+    :type default_value: str
+    :returns: The value read, or default value.
+    :rtype: str
+    """
+    prefixes = ("FDIO_CSIT_", "CSIT_", "")
+    if not isinstance(env_var_names, (list, tuple)):
+        env_var_names = [env_var_names]
+    for name in env_var_names:
+        for prefix in prefixes:
+            value = os.environ.get(prefix + name, None)
+            if value is not None:
+                return value
+    return default_value
+
+
+def get_int_from_env(env_var_names, default_value):
+    """Attempt to read int from environment variable, return that or default.
+
+    String value is read, default is returned also if conversion fails.
+
+    :param env_var_names: Base names of environment variable to attempt to read.
+    :param default_value: Value to return if read or conversion fails.
+    :type env_var_names: str, or list of str, or tuple of str
+    :type default_value: int
+    :returns: The value read, or default value.
+    :rtype: int
+    """
+    env_str = get_str_from_env(env_var_names, "")
+    try:
+        return int(env_str)
+    except ValueError:
+        return default_value
+
+
+def get_float_from_env(env_var_names, default_value):
+    """Attempt to read float from environment variable, return that or default.
+
+    String value is read, default is returned also if conversion fails.
+
+    :param env_var_names: Base names of environment variable to attempt to read.
+    :param default_value: Value to return if read or conversion fails.
+    :type env_var_names: str, or list of str, or tuple of str
+    :type default_value: float
+    :returns: The value read, or default value.
+    :rtype: float
+    """
+    env_str = get_str_from_env(env_var_names, "")
+    try:
+        return float(env_str)
+    except ValueError:
+        return default_value
+
+
+def get_pessimistic_bool_from_env(env_var_names):
+    """Attempt to read bool from environment variable, assume False by default.
+
+    Conversion is lenient and pessimistic, only few strings are considered true.
+
+    :param env_var_names: Base names of environment variable to attempt to read.
+    :type env_var_names: str, or list of str, or tuple of str
+    :returns: The value read, or False.
+    :rtype: bool
+    """
+    env_str = get_str_from_env(env_var_names, "").lower()
+    return True if env_str in ("true", "yes", "y", "1") else False
+
+
+def get_optimistic_bool_from_env(env_var_names):
+    """Attempt to read bool from environment variable, assume True by default.
+
+    Conversion is lenient and optimistic, only few strings are considered false.
+
+    :param env_var_names: Base names of environment variable to attempt to read.
+    :type env_var_names: str, or list of str, or tuple of str
+    :returns: The value read, or True.
+    :rtype: bool
+    """
+    env_str = get_str_from_env(env_var_names, "").lower()
+    return False if env_str in ("false", "no", "n", "0") else True
 
 
 class Constants(object):
@@ -112,8 +217,19 @@ class Constants(object):
     # Default path to VPP API socket.
     SOCKSVR_PATH = "/run/vpp/api.sock"
 
+    # Number of trials to execute in MRR test.
+    PERF_TRIAL_MULTIPLICITY = get_int_from_env("PERF_TRIAL_MULTIPLICITY", 10)
+
+    # Duration of one trial in MRR test.
+    PERF_TRIAL_DURATION = get_float_from_env("PERF_TRIAL_DURATION", 1.0)
+
+    # UUID string of DUT1 /tmp volume created outside of the
+    # DUT1 docker in case of vpp-device test. ${EMPTY} value means that
+    #  /tmp directory is inside the DUT1 docker.
+    DUT1_UUID = get_str_from_env("DUT1_UUID", "")
+
     # Global "kill switch" for CRC checking during runtime.
-    CRC_MISMATCH_FAILS_TEST = True
+    FAIL_ON_CRC_MISMATCH = get_optimistic_bool_from_env("FAIL_ON_CRC_MISMATCH")
 
     # Mapping from NIC name to its bps limit.
     # TODO: Implement logic to lower limits to TG NIC or software. Or PCI.
diff --git a/resources/libraries/python/PapiExecutor.py b/resources/libraries/python/PapiExecutor.py
index 0a714c182c..74ff7a0f9b 100644
--- a/resources/libraries/python/PapiExecutor.py
+++ b/resources/libraries/python/PapiExecutor.py
@@ -166,18 +166,6 @@ class PapiSocketExecutor(object):
         if self.vpp_instance:
             return
         cls = self.__class__  # Shorthand for setting class fields.
-        fail_on_mismatch = Constants.CRC_MISMATCH_FAILS_TEST
-        try:
-            from robot.libraries.BuiltIn import BuiltIn
-            from_robot = BuiltIn().get_variable_value(
-                "\${crc_mismatch_fails}", None)
-            if from_robot is not None:
-                # Robot interprets env vars as strings.
-                fail_on_mismatch = not from_robot.lower() in ("false", "n", "0")
-        except (ImportError, AttributeError):
-            # If robot is not installed or not running, or value is not string,
-            # the Constants value applies.
-            pass
         package_path = None
         tmp_dir = tempfile.mkdtemp(dir="/tmp")
         try:
@@ -199,8 +187,7 @@ class PapiSocketExecutor(object):
             api_json_directory = tmp_dir + "/usr/share/vpp/api"
             # Perform initial checks before .api.json files are gone,
             # by creating the checker instance.
-            cls.crc_checker = VppApiCrcChecker(
-                api_json_directory, fail_on_mismatch=fail_on_mismatch)
+            cls.crc_checker = VppApiCrcChecker(api_json_directory)
             # When present locally, we finally can find the installation path.
             package_path = glob.glob(tmp_dir + installed_papi_glob)[0]
             # Package path has to be one level above the vpp_papi directory.
diff --git a/resources/libraries/python/VppApiCrc.py b/resources/libraries/python/VppApiCrc.py
index d66d4d7568..cb6f5b0c60 100644
--- a/resources/libraries/python/VppApiCrc.py
+++ b/resources/libraries/python/VppApiCrc.py
@@ -43,8 +43,8 @@ class VppApiCrcChecker(object):
     so make sure the calling libraries have appropriate robot library scope.
     For usual testing, it means "GLOBAL" scope."""
 
-    def __init__(self, directory,
-                 fail_on_mismatch=Constants.CRC_MISMATCH_FAILS_TEST):
+    def __init__(
+            self, directory, fail_on_mismatch=Constants.FAIL_ON_CRC_MISMATCH):
         """Initialize empty state, then register known collections.
 
         This also scans directory for .api.json files
diff --git a/resources/libraries/robot/performance/performance_utils.robot b/resources/libraries/robot/performance/performance_utils.robot
index d809376c0f..bffd35d05e 100644
--- a/resources/libraries/robot/performance/performance_utils.robot
+++ b/resources/libraries/robot/performance/performance_utils.robot
@@ -23,6 +23,7 @@
 | Library | resources.libraries.python.TrafficGenerator.OptimizedSearch
 | Library | resources.libraries.python.TrafficGenerator.TGDropRateSearchImpl
 | Library | resources.libraries.python.Trace
+| Variables | resources/libraries/python/Constants.py
 | ...
 | Documentation
 | ... | Performance suite keywords - utilities to find and verify NDR and PDR.
@@ -396,8 +397,8 @@
 | | ... | \| Traffic should pass with maximum rate \| ${1} \| ${10.0} \
 | | ... | \| ${False} \| ${False} \| ${0} \| ${1} \|
 | | ...
-| | [Arguments] | ${trial_duration}=${perf_trial_duration}
-| | ... | ${fail_no_traffic}=${True} | ${subsamples}=${perf_trial_multiplicity}
+| | [Arguments] | ${trial_duration}=${PERF_TRIAL_DURATION}
+| | ... | ${fail_no_traffic}=${True} | ${subsamples}=${PERF_TRIAL_MULTIPLICITY}
 | | ... | ${unidirection}=${False} | ${tx_port}=${0} | ${rx_port}=${1}
 | | ...
 | | ${results} = | Send traffic at specified rate | ${trial_duration}
diff --git a/resources/libraries/robot/robot_enhancements.robot b/resources/libraries/robot/robot_enhancements.robot
deleted file mode 100644
index 7b337eafeb..0000000000
--- a/resources/libraries/robot/robot_enhancements.robot
+++ /dev/null
@@ -1,55 +0,0 @@
-# Copyright (c) 2018 Cisco and/or its affiliates.
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at:
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-*** Settings ***
-| Documentation
-| ... | Place to store general keywords, similar to ones in BuiltIn library.
-| Library | OperatingSystem
-| Library | String
-
-*** Keywords ***
-| Ensure Global Variable
-| | [Documentation] | Give default value (from environment or code) to variable.
-| | ...
-| | ... | Ideally we would just use Variables table to set global variables.
-| | ... | Unfortunately, __init__ files are special (among other things)
-| | ... | by the fact that variables set in the table are not available
-| | ... | for (sub)directory suites.
-| | ... | Therefore we are using BuiltIn.Set_Global_Variable explicitly.
-| | ... | While we are running code here, we allow environment variables
-| | ... | to override the default values.
-| | ... | If environment variable name is not specified (or empty),
-| | ... | the upper case of the variable name is used, prefixed by "CSIT_".
-| | ... | The --variable parameter to pybot takes precedence to environment.
-| | ...
-| | ... | *Arguments:*
-| | ... | - variable_name - Name of global variable to set. Type: string
-| | ... | - default_value - Value to set if not set otherwise. Type: string
-| | ... | - env_var_name - Name of environment variable to read. Type: string
-| | ... | - application - Prefix for default environment variable. Type: string
-| | ...
-| | ... | *Example:*
-| | ... | \| Ensure Global Variable \| perf_trial_duration \| 10.0 \| TRIAL_DUR
-| | ...
-| | [Arguments] | ${variable_name} | ${default_value} | ${env_var_name}=${EMPTY}
-| | ... | ${application}=CSIT
-| | ...
-| | ${env_var_length} = | Get Length | ${env_var_name}
-| | ${default_env_var} = | Convert To Uppercase | ${variable_name}
-| | ${env_var} = | Set Variable If | ${env_var_length}
-| | ... | ${env_var_name} | ${application}_${default_env_var}
-| | ${updated_default} = | Get Environment Variable
-| | ... | ${env_var} | ${default_value}
-| | ${final_value} = | Get Variable Value
-| | ... | \${${variable_name}} | ${updated_default}
-| | Set Global Variable | \${${variable_name}} | ${final_value}
diff --git a/resources/libraries/robot/shared/container.robot b/resources/libraries/robot/shared/container.robot
index 15bcad7999..cb3bc29490 100644
--- a/resources/libraries/robot/shared/container.robot
+++ b/resources/libraries/robot/shared/container.robot
@@ -16,6 +16,7 @@
 | ...
 | Library | resources.libraries.python.CpuUtils
 | Library | resources.libraries.python.topology.Topology
+| Variables | resources/libraries/python/Constants.py
 
 *** Keywords ***
 | Construct container on all DUTs
@@ -52,9 +53,9 @@
 | | :FOR | ${dut} | IN | @{duts}
 | | | ${nf_id}= | Evaluate | (${nf_chain} - ${1}) * ${nf_nodes} + ${nf_node}
 | | | ${env}= | Create List | DEBIAN_FRONTEND=noninteractive
-| | | ${dut1_uuid_length} = | Get Length | ${dut1_uuid}
+| | | ${dut1_uuid_length} = | Get Length | ${DUT1_UUID}
 | | | ${root}= | Run Keyword If | ${dut1_uuid_length}
-| | | ... | Get Docker Mergeddir | ${nodes['DUT1']} | ${dut1_uuid}
+| | | ... | Get Docker Mergeddir | ${nodes['DUT1']} | ${DUT1_UUID}
 | | | ... | ELSE | Set Variable | ${EMPTY}
 | | | ${node_arch}= | Get Node Arch | ${nodes['${dut}']}
 | | | ${mnt}= | Create List
@@ -71,7 +72,7 @@
 | | | ... | nf_chain=${nf_chain} | nf_node=${nf_node}
 | | | ... | vs_dtc=${cpu_count_int} | nf_dtc=${nf_dtc} | nf_dtcr=${nf_dtcr}
 | | | &{cont_args}= | Create Dictionary
-| | | ... | name=${dut}_${container_group}${nf_id}${dut1_uuid}
+| | | ... | name=${dut}_${container_group}${nf_id}${DUT1_UUID}
 | | | ... | node=${nodes['${dut}']} | mnt=${mnt} | env=${env}
 | | | Run Keyword If | ${pinning}
 | | | ... | Set To Dictionary | ${cont_args} | cpuset_cpus=${nf_cpus}
diff --git a/resources/libraries/robot/shared/memif.robot b/resources/libraries/robot/shared/memif.robot
index 0fda454764..a0fae656f9 100644
--- a/resources/libraries/robot/shared/memif.robot
+++ b/resources/libraries/robot/shared/memif.robot
@@ -15,6 +15,7 @@
 | Documentation | Memif interface keyword library.
 | ...
 | Library | resources.libraries.python.Memif
+| Variables | resources/libraries/python/Constants.py
 
 *** Keywords ***
 | Set up memif interfaces on DUT node
@@ -56,10 +57,10 @@
 | | ${sid_1}= | Evaluate | (${mid}*2)-1
 | | ${sid_2}= | Evaluate | (${mid}*2)
 | | ${memif_1}= | Create memif interface | ${dut_node}
-| | ... | ${filename1}${mid}${dut1_uuid}-${sid_1} | ${mid} | ${sid_1}
+| | ... | ${filename1}${mid}${DUT1_UUID}-${sid_1} | ${mid} | ${sid_1}
 | | ... | rxq=${rxq} | txq=${txq} | role=${role}
 | | ${memif_2}= | Create memif interface | ${dut_node}
-| | ... | ${filename2}${mid}${dut1_uuid}-${sid_2} | ${mid} | ${sid_2}
+| | ... | ${filename2}${mid}${DUT1_UUID}-${sid_2} | ${mid} | ${sid_2}
 | | ... | rxq=${rxq} | txq=${txq} | role=${role}
 | | Set Interface State | ${dut_node} | ${memif_1} | up
 | | Set Interface State | ${dut_node} | ${memif_2} | up
diff --git a/resources/libraries/robot/shared/test_teardown.robot b/resources/libraries/robot/shared/test_teardown.robot
index e130038fbc..5d2c2fa165 100644
--- a/resources/libraries/robot/shared/test_teardown.robot
+++ b/resources/libraries/robot/shared/test_teardown.robot
@@ -17,6 +17,7 @@
 | Resource | resources/libraries/robot/shared/container.robot
 | Library | resources.libraries.python.PapiHistory
 | Library | resources.libraries.python.topology.Topology
+| Variables | resources/libraries/python/Constants.py
 | ...
 | Documentation | Test teardown keywords.
 
@@ -44,7 +45,7 @@
 | | ... | Additional teardown for tests which uses performance measurement.
 | | ...
 | | Run Keyword If Test Failed
-| | ... | Send traffic at specified rate | ${perf_trial_duration} | 10000pps
+| | ... | Send traffic at specified rate | ${PERF_TRIAL_DURATION} | 10000pps
 | | ... | ${frame_size} | ${traffic_profile} | pkt_trace=${True}
 
 | Additional Test Tear Down Action For packet_trace