fix: random failings from subprocesses and command formatting (#935)

* fix: random failings from subprocesses

    async executions of muliple processes leads to various errors.
    eg: get-app operation runs a "git clone" at the same time "pip
    install" is run. This causes failures as the folder either doesnt
    exist or isnt complete.

    Proposed solution to this is to execute blocking subprocesseses

* style: command logging format via exec_cmd

bench/utils.py

@@ -28,6 +28,7 @@ class color:
 	green = '\033[92m'
 	yellow = '\033[93m'
 	red = '\033[91m'
+	silver = '\033[90m'
 
 
 def is_bench_directory(directory=os.path.curdir):
@@ -172,26 +173,11 @@ def clone_apps_from(bench_path, clone_from, update_app=True):
 		setup_app(app)
 
 def exec_cmd(cmd, cwd='.'):
-	from .cli import from_command_line
+	import shlex
-
-	is_async = False if from_command_line else True
-	if is_async:
-		stderr = stdout = subprocess.PIPE
-	else:
-		stderr = stdout = None
-
 	logger.info(cmd)
-
+	cmd = shlex.split(cmd)
-	p = subprocess.Popen(cmd, cwd=cwd, shell=True, stdout=stdout, stderr=stderr,
+	print("{0}$ {1}{2}".format(color.silver, cmd, color.nc))
-		universal_newlines=True)
+	subprocess.call(cmd, cwd=cwd, universal_newlines=True)
-
-	if is_async:
-		return_code = print_output(p)
-	else:
-		return_code = p.wait()
-
-	if return_code > 0:
-		raise CommandFailedError(cmd)
 
 def which(executable, raise_err = False):
 	from distutils.spawn import find_executable