import: Colour error messages red, and output them inline with status

Previously errors from subprocesses went to stdout straight away, and
were then reported at the end of the run. Other BaserockImportException
error messages were never printed at all.

Now all errors are printed as they happen, and are coloured red so that
they are easy to find even in lots of status output.

This adds a dependency on the 'ansicolor' module, available from PyPI.

1 files changed, 30 insertions, 9 deletions

diff --git a/import/main.py b/import/main.py
index c174dc62..5d906320 100644
--- a/import/main.py
+++ b/import/main.py
@@ -17,6 +17,7 @@
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
 
+import ansicolor
 import cliapp
 import morphlib
 import networkx
@@ -307,7 +308,6 @@ def run_extension(filename, args, cwd='.'):
 
     def report_extension_stderr(line):
         errors.append(line)
-        sys.stderr.write('%s\n' % line)
 
     def report_extension_logger(line):
         ext_logger.debug(line)
@@ -364,12 +364,28 @@ class BaserockImportApplication(cliapp.Application):
                               "error",
                               default=False)
 
+    def _stream_has_colours(self, stream):
+        # http://blog.mathieu-leplatre.info/colored-output-in-console-with-python.html
+        if not hasattr(stream, "isatty"):
+            return False
+        if not stream.isatty():
+            return False # auto color only on TTYs
+        try:
+            import curses
+            curses.setupterm()
+            return curses.tigetnum("colors") > 2
+        except:
+            # guess false in case of error
+            return False
+
     def setup(self):
         self.add_subcommand('omnibus', self.import_omnibus,
                             arg_synopsis='REPO PROJECT_NAME SOFTWARE_NAME')
         self.add_subcommand('rubygems', self.import_rubygems,
                             arg_synopsis='GEM_NAME')
 
+        self.stdout_has_colours = self._stream_has_colours(sys.stdout)
+
     def setup_logging_formatter_for_file(self):
         root_logger = logging.getLogger()
         root_logger.name = 'main'
@@ -386,9 +402,18 @@ class BaserockImportApplication(cliapp.Application):
 
         super(BaserockImportApplication, self).process_args(args)
 
-    def status(self, msg, *args):
-        print msg % args
-        logging.info(msg % args)
+    def status(self, msg, *args, **kwargs):
+        text = msg % args
+        if kwargs.get('error') == True:
+            logging.error(text)
+            if self.stdout_has_colours:
+                sys.stdout.write(ansicolor.red(text))
+            else:
+                sys.stdout.write(text)
+        else:
+            logging.info(text)
+            sys.stdout.write(text)
+        sys.stdout.write('\n')
 
     def import_omnibus(self, args):
         '''Import a software component from an Omnibus project.
@@ -552,9 +577,7 @@ class BaserockImportApplication(cliapp.Application):
                 runtime_deps = self.get_dependencies_from_morphology(
                     chunk_morph, 'x-runtime-dependencies-%s' % kind)
             except BaserockImportException as e:
-                # Don't print the exception on stdout; the error messages will
-                # have gone to stderr already.
-                logging.error(str(e))
+                self.status(str(e), error=True)
                 errors[current_item] = e
                 build_deps = runtime_deps = {}
 
@@ -566,8 +589,6 @@ class BaserockImportApplication(cliapp.Application):
                 current_item, runtime_deps, to_process, processed, False)
 
         if len(errors) > 0:
-            for package, exception in errors.iteritems():
-                self.status('\n%s: %s', package.name, exception)
             self.status(
                 '\nErrors encountered, not generating a stratum morphology.')
             self.status(