Add a standard 'light' palette

For use in a terminal with a white background.  Also add a config
file option that selects the default palette.

Change-Id: I1b4a61efa3d9011bfe089471fa80ad4563d9ba01

gertty.yaml-sample

@@ -15,6 +15,9 @@ palettes:
     test-SUCCESS: ['light green', '', '']
     test-FAILURE: ['light red', '', '']
 
+# Uncomment the next line if your terminal has a white background
+# palette: light
+
 commentlinks:
   - match: "^- (?P<job>.*?) (?P<url>.*?) : (?P<result>[^ ]+) ?(?P<comment>.*)$"
     test-result: "{job}"

gertty/config.py

@@ -92,6 +92,7 @@ class ConfigSchema(object):
     def getSchema(self, data):
         schema = v.Schema({v.Required('servers'): self.servers,
                            'palettes': self.palettes,
+                           'palette': str,
                            'commentlinks': self.commentlinks,
                            'dashboards': self.dashboards,
                            'reviewkeys': self.reviewkeys,
@@ -133,12 +134,15 @@ class Config(object):
         log_file = server.get('log_file', '~/.gertty.log')
         self.log_file = os.path.expanduser(log_file)
 
-        self.palettes = {}
+        self.palettes = {'default': gertty.palette.Palette({}),
+                         'light': gertty.palette.Palette(gertty.palette.LIGHT_PALETTE),
+                         }
         for p in self.config.get('palettes', []):
-            self.palettes[p['name']] = gertty.palette.Palette(p)
-        if not self.palettes:
-            self.palettes['default'] = gertty.palette.Palette({})
-        self.palette = self.palettes[palette]
+            if p['name'] not in self.palettes:
+                self.palettes[p['name']] = gertty.palette.Palette(p)
+            else:
+                self.palettes[p['name']].update(p)
+        self.palette = self.palettes[self.config.get('palette', palette)]
 
         self.commentlinks = [gertty.commentlink.CommentLink(c)
                              for c in self.config.get('commentlinks', [])]

gertty/palette.py

@@ -75,10 +75,30 @@ DEFAULT_PALETTE={
     'focused-reviewed-change': ['dark gray,standout', ''],
     }
 
+# A delta from the default palette
+LIGHT_PALETTE = {
+    'table-header': ['black,bold', ''],
+    'unreviewed-project': ['black', ''],
+    'subscribed-project': ['dark gray', ''],
+    'unsubscribed-project': ['dark gray', ''],
+    'focused-unreviewed-project': ['black,standout', ''],
+    'focused-subscribed-project': ['dark gray,standout', ''],
+    'focused-unsubscribed-project': ['dark gray,standout', ''],
+    'change-data': ['dark blue,bold', ''],
+    'reviewer-name': ['brown', ''],
+    'change-message-name': ['brown', ''],
+    'change-message-header': ['black', ''],
+    'focused-link': ['dark blue,bold', ''],
+    'filename': ['dark cyan', ''],
+    }
+
 class Palette(object):
     def __init__(self, config):
         self.palette = {}
         self.palette.update(DEFAULT_PALETTE)
+        self.update(config)
+
+    def update(self, config):
         d = config.copy()
         if 'name' in d:
             del d['name']