Improve gerrit_dash_creator.cmd.creator

* use configparser instead of self written parsing
  (add new method read_dashboard_file)

* remove methods get_title and get_sections

* add requirement six (ConfigParser in Python2,
  configparser in Python3)

* remove import re and fileinput

* check if dashboard file exist and is readable before
  trying to parse it (new imports os and os.path)

* slighly change the output to be more informative

* add new parameter in section dashboard to make the
  base URL configurable

* check if necessary options in the used dashboard
  file are available

* improve exception handling and error output

* rename generate_url to generate_dashboard_url

* use correct exit codes (correct return values in the
  main method)

* rename internal argument name dash to dashboard_file

* add missing doc strings

Change-Id: Ifcaf20f7495b5619db30ac0046909b334672f756

gerrit_dash_creator/cmd/creator.py

@@ -13,76 +13,97 @@
 # under the License.
 
 import argparse
-import fileinput
-import re
+import os
+import os.path
 import sys
 import urllib
 
+from six.moves import configparser
+
 
 def escape_comma(buff):
     """Because otherwise Firefox is a sad panda."""
     return buff.replace(',', '%2c')
 
 
-def get_title(fname):
-    title = ""
-    foreach = ""
-    for line in fileinput.input(fname):
-        m = re.match("title = (.+)", line)
-        if m:
-            title = m.group(1)
+def generate_dashboard_url(dashboard):
+    """Generate a dashboard URL from a given definition."""
+    try:
+        title = dashboard.get('dashboard', 'title')
+    except configparser.NoOptionError:
+        raise ValueError("option 'title' in section 'dashboard' not set")
 
-        m = re.match("foreach = (.+)", line)
-        if m:
-            foreach = escape_comma(m.group(1))
-    fileinput.close()
-    return title, foreach
+    try:
+        foreach = escape_comma(dashboard.get('dashboard', 'foreach'))
+    except configparser.NoOptionError:
+        raise ValueError("option 'foreach' in section 'dashboard' not set")
 
+    try:
+        baseurl = dashboard.get('dashboard', 'baseurl')
+    except configparser.NoOptionError:
+        baseurl = 'https://review.openstack.org/#/dashboard/?'
 
-def get_sections(fname):
-    sections = []
-    sname = None
-    for line in fileinput.input(fname):
-        m = re.match('\[section "([^"]+)', line)
-        if m:
-            sname = m.group(1)
-        elif sname:
-            m = re.match("query = (.+)", line)
-            if m:
-                query = escape_comma(m.group(1))
-
-                sections.append({'title': sname, 'query': query})
-    fileinput.close()
-    return sections
-
-
-def gen_url(title, foreach, sections):
-    base = 'https://review.openstack.org/#/dashboard/?'
+    base = baseurl
     base += urllib.urlencode({'title': title, 'foreach': foreach})
     base += '&'
-    encoded = [urllib.urlencode({x['title']: x['query']}) for x in sections]
-    base += '&'.join(encoded)
+    for section in dashboard.sections():
+        if not section.startswith('section'):
+            continue
+
+        try:
+            query = dashboard.get(section, 'query')
+        except configparser.NoOptionError:
+            raise ValueError("option 'query' in '%s' not set" % section)
+
+        title = section[9:-1]
+        encoded = urllib.urlencode({title: query})
+        base += "&%s" % encoded
     return base
 
 
 def get_options():
+    """Parse command line arguments and options."""
     parser = argparse.ArgumentParser(
-        description='Create a gerrit dashboard URL from a dashboard '
-                    'definition')
-    parser.add_argument('dash',
+        description='Create a Gerrit dashboard URL from a dashboard '
+                    'definition file')
+    parser.add_argument('dashboard_file',
                         metavar='dashboard_file',
-                        help="Dashboard file to create url from")
+                        help='Dashboard definition file to create URL from')
     return parser.parse_args()
 
 
+def read_dashboard_file(fname):
+    """Read and parse a dashboard definition from a specified file."""
+    dashboard = configparser.ConfigParser()
+    dashboard.readfp(open(fname))
+    return dashboard
+
+
 def main():
+    """Entrypoint."""
     opts = get_options()
-    title, foreach = get_title(opts.dash)
-    sections = get_sections(opts.dash)
-    url = gen_url(title, foreach, sections)
-    print("URL for %s" % title)
+
+    if (not os.path.isfile(opts.dashboard_file) or
+            not os.access(opts.dashboard_file, os.R_OK)):
+        print("error: dashboard file '%s' is missing or is not readable" %
+              opts.dashboard_file)
+        return 1
+
+    dashboard = read_dashboard_file(opts.dashboard_file)
+
+    try:
+        url = generate_dashboard_url(dashboard)
+    except ValueError as e:
+        print("error:\tgenerating dashboard '%s' failed\n\t%s" %
+              (opts.dashboard_file, e))
+        return 1
+
+    print("Generated URL for the Gerrit dashboard '%s':" % opts.dashboard_file)
+    print("")
     print(url)
 
+    return 0
+
 
 if __name__ == '__main__':
     sys.exit(main())

requirements.txt

@@ -1,2 +1,3 @@
 argparse
 pbr>=0.6,!=0.7,<1.0
+six>=1.7.0