Print mock output when building with MockBuilder

Currently when building RPMs or SRPMs with MockBuilder, tito will not print the
output from mock. This makes diagnosis harder especially in CI
environments.

This PR will do the following changes:

1. If `--quiet` option is not specified, `run_command_print` will be used to
run the `mock` or `rpmbuild` command. Otherwise we will continue to use
`run_command`.
2. `run_command_print` will print error message when an error happens, like what `run_command`
does.

src/tito/builder/main.py

@@ -225,7 +225,8 @@ class BuilderBase(object):
             ' "_binary_filedigest_algorithm md5" %s %s %s --nodeps -bs %s' % (
                 rpmbuild_options, self._get_rpmbuild_dir_options(),
                 define_dist, self.spec_file))
-        output = run_command_print(cmd)
+        run_command_func = run_command if self.quiet else run_command_print
+        output = run_command_func(cmd)
         self.srpm_location = find_wrote_in_rpmbuild_output(output)[0]
         self.artifacts.append(self.srpm_location)
 
@@ -1142,25 +1143,26 @@ class MockBuilder(Builder):
             self.normal_builder.cleanup()
 
     def _build_in_mock(self):
+        run_command_func = run_command if self.quiet else run_command_print
         if not self.speedup:
             print("Initializing mock...")
-            run_command("mock %s -r %s --init" % (self.mock_cmd_args, self.mock_tag))
+            run_command_func("mock %s -r %s --init" % (self.mock_cmd_args, self.mock_tag))
         else:
             print("Skipping mock --init due to speedup option.")
 
         print("Installing deps in mock...")
-        run_command("mock %s -r %s %s" % (
+        run_command_func("mock %s -r %s %s" % (
             self.mock_cmd_args, self.mock_tag, self.srpm_location))
         print("Building RPMs in mock...")
-        run_command('mock %s -r %s --rebuild %s' %
+        run_command_func('mock %s -r %s --rebuild %s' %
                 (self.mock_cmd_args, self.mock_tag, self.srpm_location))
         mock_output_dir = os.path.join(self.rpmbuild_dir, "mockoutput")
-        run_command("mock %s -r %s --copyout /builddir/build/RPMS/ %s" %
+        run_command_func("mock %s -r %s --copyout /builddir/build/RPMS/ %s" %
                 (self.mock_cmd_args, self.mock_tag, mock_output_dir))
 
         # Copy everything mock wrote out to /tmp/tito:
         files = os.listdir(mock_output_dir)
-        run_command("cp -v %s/*.rpm %s" %
+        run_command_func("cp -v %s/*.rpm %s" %
                 (mock_output_dir, self.rpmbuild_basedir))
         print
         info_out("Wrote:")

src/tito/common.py

@@ -443,16 +443,29 @@ def run_command_print(command):
     output = []
     env = os.environ.copy()
     env['LC_ALL'] = 'C'
-    p = subprocess.Popen(shlex.split(command),
-        stdout=subprocess.PIPE, stderr=subprocess.STDOUT, env=env,
-        universal_newlines=True)
-    for line in run_subprocess(p):
-        line = line.rstrip('\n')
-        print(line)
-        output.append(line)
-    print("\n"),
-    if p.poll() > 0:
-        raise RunCommandException(command, p.poll(), "\n".join(output))
+    p = None
+    try:
+        p = subprocess.Popen(shlex.split(command),
+            stdout=subprocess.PIPE, stderr=subprocess.STDOUT, env=env,
+            universal_newlines=True)
+    except OSError as e:
+        status = e.errno
+        output = e.strerror
+    if p:
+        for line in run_subprocess(p):
+            line = line.rstrip('\n')
+            print(line)
+            output.append(line)
+        print("\n"),
+        status = p.poll()
+    if status > 0:
+        msgs = [
+            "Error running command: %s\n" % command,
+            "Status code: %s\n" % status,
+            "Command output: %s\n" % output,
+        ]
+        error_out(msgs, die=False)
+        raise RunCommandException(command, status, "\n".join(output))
     return '\n'.join(output)
 
 
@@ -462,7 +475,7 @@ def run_subprocess(p):
         line = p.stdout.readline()
         if len(line) > 0:
             yield line
-        if(retcode is not None):
+        if retcode is not None:
             break