Use py3 over py2 (#850)

1. Prefer py3 over py2
2. Addressing issue with omsagent installation when python 2&3 coexists
3. Addressing execution issue when english is not system default language

Author: samarth793

LCM/dsc/engine/ConsistencyInvoker/ConsistencyInvoker.c

@@ -61,7 +61,7 @@ char* getPythonProvider()
     char* result = malloc(1);
     *result = 0; 
 
-    FILE* pipe = popen("python2 --version 2>&1", "r");   
+    FILE* pipe = popen("python3 -V 2>&1 | grep -Po '(?<=Python )(.+)'", "r");   
     if(!pipe) {
         printf("Cant start command.");
     }
@@ -70,15 +70,15 @@ char* getPythonProvider()
         strcat(result,buffer);
     }
 
-    // If python2 --version does not contain 'not found' return python2
-    if(strstr(result, "not found") == NULL) {
-    	return PYTHON2_COMMAND;
+    // If python3 --version exists
+    if(*result != '\0' && result[0] == '3') {
+    	return PYTHON3_COMMAND;
     }
 
-    // Look for python3
+    // Look for python2
     result = malloc(1);
     *result = 0;
-    pipe = popen("python3 --version 2>&1", "r");
+    pipe = popen("python2 -V 2>&1 | grep -Po '(?<=Python )(.+)'", "r");
     if(!pipe) {
     	printf("Cant start command.");
     }
@@ -87,11 +87,10 @@ char* getPythonProvider()
         strcat(result,buffer);
     }
 
-    // If python3 --version does not contain 'not found' return python3
-    if(strstr(result, "not found") == NULL) {
-	    return PYTHON3_COMMAND;
+    // If python2 --version exists
+    if(*result != '\0' && result[0] == '2') {
+	    return PYTHON2_COMMAND;
     }
 
     return PYTHON_COMMAND;
-
 }

LCM/dsc/engine/ca/CAInfrastructure/WebPullClient.c

@@ -2076,24 +2076,21 @@ MI_Result MI_CALL Pull_GetModules(_Out_ MI_Uint32 * numModulesInstalled,
         int isPython2 = 1;
         DSC_LOG_INFO("Assuming python2 in WebPullClient\n");
 
-	// Look for python2
-        FILE * pipe = popen("python2 --version 2>&1", "r");
+	    // Look for python3
+        FILE * pipe = popen("python3 -V 2>&1 | grep -Po '(?<=Python )(.+)'", "r");
         fgets(data, BUFSIZ, pipe);
-        if (!strstr(data, "not found"))
-        {
-            DSC_LOG_INFO("Found python2 in WebPullClient.\n");
-                isPython2 = 1;
-            }
-        else
-        {
-            // If python2 does not exist, look for python3
+        if (data[0] == '3') {
+            DSC_LOG_INFO("Found python3 in WebPullClient.\n");
+            isPython2 = 0;
+        } else {
+            // If python3 does not exist, look for python2
             memset(&data[0], 0, sizeof(data));
-                pipe = popen("python3 --version 2>&1", "r");
-                fgets(data, BUFSIZ, pipe);
-            if (!strstr(data, "not found")) {
-                DSC_LOG_INFO("Found python3 in WebPullClient.\n");
-                    isPython2 = 0;
-                }
+            pipe = popen("python2 -V 2>&1 | grep -Po '(?<=Python )(.+)'", "r");
+            fgets(data, BUFSIZ, pipe);
+            if (data[0] == '2') {
+                DSC_LOG_INFO("Found python2 in WebPullClient.\n");
+                    isPython2 = 1;
+            }
         }
 
       	if (isPython2 == 1)

LCM/scripts/GetDscConfiguration.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python2
 import fileinput
 import sys
 import subprocess

LCM/scripts/GetDscLocalConfigurationManager.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python2
 import fileinput
 import sys
 import subprocess

LCM/scripts/InstallModule.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python2
 import imp
 import os
 import stat
@@ -66,7 +66,7 @@ def getPlatformArchitectureFolderName():
 
 def regenerateDscPythonScriptInitFiles():
     regenerateInitFilesScriptPath = join(helperlib.DSC_SCRIPT_PATH, 'RegenerateInitFiles.py')
-    regenerateInitFilesResult = subprocess.call("(python " + regenerateInitFilesScriptPath + ")", shell=True)
+    regenerateInitFilesResult = subprocess.call("(python2 " + regenerateInitFilesScriptPath + ")", shell=True)
     if regenerateInitFilesResult != 0:
         exitWithError("Failed to regenerate the DSC __init__.py files with the result code", regenerateInitFilesResult)
 

LCM/scripts/OMS_MetaConfigHelper.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python2
 import os
 import sys
 import imp

LCM/scripts/OmsConfigHostHelpers.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python2
 import json
 import time
 import datetime

LCM/scripts/OperationStatusUtility.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python2
 from datetime   import datetime
 from errno      import EINVAL
 from imp        import load_source

LCM/scripts/PerformInventory.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python2
 from fcntl                import flock, LOCK_EX, LOCK_UN, LOCK_NB
 from imp                  import load_source
 from os                   import listdir, system

LCM/scripts/PerformRequiredConfigurationChecks.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python2
 import sys
 from imp        import load_source
 from os.path    import dirname, join, realpath, isfile