in case of command failure, log the stdout and stderr and raise an ex…

…ception

azurelinuxagent/common/utils/cryptutil.py

@@ -53,24 +53,24 @@ def get_pubkey_from_prv(self, file_name):
         if not os.path.exists(file_name):
             raise IOError(errno.ENOENT, "File not found", file_name)
         else:
-            cmd = "{0} pkey -in {1} -pubout 2>/dev/null".format(self.openssl_cmd, file_name)
-            pub = shellutil.run_get_output(cmd)[1]
+            cmd = "{0} pkey -in {1} -pubout".format(self.openssl_cmd, file_name)
+            pub = shellutil.run_command(cmd.split(" "))
             return pub
 
     def get_pubkey_from_crt(self, file_name):
         if not os.path.exists(file_name):
             raise IOError(errno.ENOENT, "File not found", file_name)
         else:
-            cmd = "{0} x509 -in {1} -pubkey -noout 2>/dev/null".format(self.openssl_cmd, file_name)
-            pub = shellutil.run_get_output(cmd)[1]
+            cmd = "{0} x509 -in {1} -pubkey -noout".format(self.openssl_cmd, file_name)
+            pub = shellutil.run_command(cmd.split(" "))
             return pub
 
     def get_thumbprint_from_crt(self, file_name):
         if not os.path.exists(file_name):
             raise IOError(errno.ENOENT, "File not found", file_name)
         else:
-            cmd = "{0} x509 -in {1} -fingerprint -noout 2>/dev/null".format(self.openssl_cmd, file_name)
-            thumbprint = shellutil.run_get_output(cmd)[1]
+            cmd = "{0} x509 -in {1} -fingerprint -noout".format(self.openssl_cmd, file_name)
+            thumbprint = shellutil.run_command(cmd.split(" "))
             thumbprint = thumbprint.rstrip().split('=')[1].replace(':', '').upper()
             return thumbprint
 

azurelinuxagent/common/utils/shellutil.py

@@ -110,6 +110,34 @@ def run_get_output(cmd, chk_err=True, log_cmd=True, expected_errors=[]):
     return 0, output
 
 
+def _encode_command_output(output):
+    return ustr(output, encoding='utf-8', errors="backslashreplace")
+
+
+def run_command(command):
+    """
+    Wrapper for subprocess.Popen.
+    Executes the given command and returns its stdout. Logs any errors executing the command and raises an exception.
+    """
+    try:
+        process = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=False)
+        stdout, stderr = process.communicate()
+        retcode = process.returncode
+
+        if retcode:
+            logger.error(u"Command: [{0}], return code: [{1}], "
+                         u"stdout: [{2}] stderr: [{3}]".format(command,
+                                                               retcode,
+                                                               _encode_command_output(stdout),
+                                                               _encode_command_output(stderr)))
+            raise subprocess.CalledProcessError(retcode, command)
+    except Exception as e:
+        logger.error(u"Command [{0}] raised unexpected exception: [{1}]".format(command, ustr(e)))
+        raise
+
+    return _encode_command_output(stdout)
+
+
 def quote(word_list):
     """
     Quote a list or tuple of strings for Unix Shell as words, using the

tests/utils/test_shell_util.py

@@ -21,6 +21,7 @@
 import unittest
 import os
 import azurelinuxagent.common.utils.shellutil as shellutil
+import subprocess
 import test
 
 
@@ -142,5 +143,40 @@ def test_it_should_log_unexpected_errors_as_errors(self):
         self.assertEquals(mock_logger.warn.call_count, 0)
 
 
+class RunCommandTestCase(AgentTestCase):
+    def test_run_command_it_should_run_without_errors(self):
+        command = "echo 42".split(" ")
+
+        with patch("azurelinuxagent.common.utils.shellutil.logger", autospec=True) as mock_logger:
+            ret = shellutil.run_command(command)
+            self.assertEquals(ret, "42\n")
+            self.assertEquals(mock_logger.error.call_count, 0)
+
+    def test_run_command_it_should_raise_an_exception_file_not_found(self):
+        command = "ls nonexistent_file".split(" ")
+        expected_returncode = 2
+
+        with patch("azurelinuxagent.common.utils.shellutil.logger") as mock_logger:
+            with self.assertRaises(subprocess.CalledProcessError) as context_manager:
+                shellutil.run_command(command)
+
+            ex = context_manager.exception
+            self.assertEquals(subprocess.CalledProcessError, type(ex))
+            self.assertEquals((expected_returncode, ["ls", "nonexistent_file"]), ex.args)
+
+            self.assertEquals(mock_logger.error.call_count, 2)
+
+            logged_error_first = "Command: [{0}], return code: [{1}], " \
+                                 "stdout: [] stderr: [{2}]".format(command, expected_returncode,
+                                                                   "ls: cannot access 'nonexistent_file': "
+                                                                   "No such file or directory\n")
+            self.assertEquals(mock_logger.error.call_args_list[0][0][0], logged_error_first)
+
+            logged_error_second = "Command [{0}] raised unexpected exception: " \
+                                  "[Command '{0}' returned non-zero exit status {1}.]".format(command,
+                                                                                              expected_returncode)
+            self.assertEquals(mock_logger.error.call_args_list[1][0][0], logged_error_second)
+
+
 if __name__ == '__main__':
     unittest.main()