new CLI command brother_ql info version (#34)

brother_ql/cli.py

@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 
 # Python standard library
-import logging
+import logging, sys
 
 # external dependencies
 import click
@@ -52,7 +52,7 @@ def discover_and_list_available_devices(backend):
     print(textual_description_discovered_devices(available_devices))
 
 @cli.command()
-@click.argument('info', click.Choice(('labels', 'models')))
+@click.argument('info', click.Choice(('labels', 'models', 'version')))
 @click.pass_context
 def info(ctx, *args, **kwargs):
     """ list available choices (for labels or models) """
@@ -74,6 +74,19 @@ def info(ctx, *args, **kwargs):
         from brother_ql.output_helpers import textual_label_description
         print(textual_label_description(label_sizes))
 
+    elif kwargs['info'] == 'version':
+        """
+        Show the version of the package in the form:
+        ``brother_ql VERSION_STRING``
+        """
+        try:
+            import pkg_resources
+            version = pkg_resources.get_distribution("brother_ql").version
+            print("brother_ql %s" % version)
+        except:
+            logger.error("Couln't determine the version of the brother_ql package.")
+            sys.exit(1)
+
 @cli.command('print', short_help='Print a label')
 @click.argument('images', nargs=-1, metavar='IMAGE [IMAGE] ...')
 @click.option('-l', '--label', type=click.Choice(label_sizes), envvar='BROTHER_QL_LABEL', help='The label (size, type - die-cut or endless). Run `brother_ql info labels` for a full list including ideal pixel dimensions.')