Consolidate status results

All the _list functions return the same thing; save the results and
use a common output function to generate the json or text output.

Change-Id: I9cb44b09de2cb948e7381ef10302b21040433a2c

nodepool/cmd/nodepoolcmd.py

@@ -156,13 +156,16 @@ class NodePoolCmd(NodepoolApp):
     def list(self, node_id=None, detail=False):
         if hasattr(self.args, 'detail'):
             detail = self.args.detail
-        print(status.node_list(self.zk, node_id, detail))
+        results = status.node_list(self.zk, node_id, detail)
+        print(status.output(results, 'pretty'))
 
     def dib_image_list(self):
-        print(status.dib_image_list(self.zk))
+        results = status.dib_image_list(self.zk)
+        print(status.output(results, 'pretty'))
 
     def image_list(self):
-        print(status.image_list(self.zk))
+        results = status.image_list(self.zk)
+        print(status.output(results, 'pretty'))
 
     def image_build(self, diskimage=None):
         diskimage = diskimage or self.args.image
@@ -334,7 +337,8 @@ class NodePoolCmd(NodepoolApp):
         # TODO(asselin,yolanda): add validation of secure.conf
 
     def request_list(self):
-        print(status.request_list(self.zk))
+        results = status.request_list(self.zk)
+        print(status.output(results, 'pretty'))
 
     def _wait_for_threads(self, threads):
         for t in threads:

nodepool/status.py

@@ -20,6 +20,29 @@ import time
 
 from prettytable import PrettyTable
 
+# General notes:
+#
+# All the _list functions should return a tuple
+#
+#  ([ {obj}, {obj}, ...], headers_table)
+#
+# The headers_table is an OrderedDict that maps the fields in the
+# returned objs to pretty-printable headers.  Each obj in the list
+# should be a dictionary with fields as described by the
+# headers_table.
+#
+# e.g.
+#
+#   headers_table = OrderedDict({
+#         'key1': 'Key One',
+#         'key2': 'Key Two'})
+#   objs = [ { 'key1': 'value', 'key2': 123 },
+#            { 'key1': 'value2', 'key2': 456 } ]
+#   return(objs, headers_table)
+#
+# The output() function takes this tuple result and a format to
+# produce results for consumption by the caller.
+
 
 def age(timestamp):
     now = time.time()
@@ -53,7 +76,18 @@ def _to_pretty_table(objs, headers_table):
     return t
 
 
-def node_list(zk, node_id=None, detail=False, format='pretty'):
+def output(results, fmt):
+    objs, headers_table = results
+    if fmt == 'pretty':
+        t = _to_pretty_table(objs, headers_table)
+        return str(t)
+    elif fmt == 'json':
+        return json.dumps(objs)
+    else:
+        raise ValueError('Unknown format "%s"' % fmt)
+
+
+def node_list(zk, node_id=None, detail=False):
     headers_table = [
         ("id", "ID"),
         ("provider", "Provider"),
@@ -126,16 +160,10 @@ def node_list(zk, node_id=None, detail=False, format='pretty'):
             objs.append(dict(zip(headers_table.keys(),
                                  values)))
 
-    if format == 'pretty':
+    return (objs, headers_table)
-        t = _to_pretty_table(objs, headers_table)
-        return str(t)
-    elif format == 'json':
-        return json.dumps(objs)
-    else:
-        raise ValueError('Unknown format "%s"' % format)
 
 
-def dib_image_list(zk, format='pretty'):
+def dib_image_list(zk):
     headers_table = OrderedDict([
         ("id", "ID"),
         ("image", "Image"),
@@ -154,16 +182,10 @@ def dib_image_list(zk, format='pretty'):
                          'state': build.state,
                          'age': int(build.state_time)
                          })
-    if format == 'pretty':
+    return (objs, headers_table)
-        t = _to_pretty_table(objs, headers_table)
-        return str(t)
-    elif format == 'json':
-        return json.dumps(objs)
-    else:
-        raise ValueError('Unknown format "%s"' % format)
 
 
-def image_list(zk, format='pretty'):
+def image_list(zk):
     headers_table = OrderedDict([
         ("id", "Build ID"),
         ("upload_id", "Upload ID"),
@@ -188,16 +210,10 @@ def image_list(zk, format='pretty'):
                               int(upload.state_time)]
                     objs.append(dict(zip(headers_table.keys(),
                                          values)))
-    if format == 'pretty':
+    return (objs, headers_table)
-        t = _to_pretty_table(objs, headers_table)
-        return str(t)
-    elif format == 'json':
-        return json.dumps(objs)
-    else:
-        raise ValueError('Unknown format "%s"' % format)
 
 
-def request_list(zk, format='pretty'):
+def request_list(zk):
     headers_table = OrderedDict([
         ("id", "Request ID"),
         ("state", "State"),
@@ -213,10 +229,4 @@ def request_list(zk, format='pretty'):
                   req.declined_by]
         objs.append(dict(zip(headers_table.keys(),
                              values)))
-    if format == 'pretty':
+    return (objs, headers_table)
-        t = _to_pretty_table(objs, headers_table)
-        return str(t)
-    elif format == 'json':
-        return json.dumps(objs)
-    else:
-        raise ValueError('Unknown format "%s"' % format)

nodepool/webapp.py

@@ -84,34 +84,29 @@ class WebApp(threading.Thread):
         result = self.cache.get(index)
         if result:
             return result
+
+        if path.endswith('.json'):
+            out_fmt = 'json'
+            path = path[:-5]
+        else:
+            out_fmt = 'pretty'
+
+        zk = self.nodepool.getZK()
+
         if path == '/image-list':
-            output = status.image_list(self.nodepool.getZK(),
+            results = status.image_list(zk)
-                                       format='pretty')
-        elif path == '/image-list.json':
-            output = status.image_list(self.nodepool.getZK(),
-                                       format='json')
         elif path == '/dib-image-list':
-            output = status.dib_image_list(self.nodepool.getZK(),
+            results = status.dib_image_list(zk)
-                                           format='pretty')
-        elif path == '/dib-image-list.json':
-            output = status.dib_image_list(self.nodepool.getZK(),
-                                           format='json')
         elif path == '/node-list':
-            output = status.node_list(self.nodepool.getZK(),
+            results = status.node_list(zk,
-                                      format='pretty',
+                                       node_id=params.get('node_id'))
-                                      node_id=params.get('node_id'))
-        elif path == '/node-list.json':
-            output = status.node_list(self.nodepool.getZK(),
-                                      format='json',
-                                      node_id=params.get('node_id'))
         elif path == '/request-list':
-            output = status.request_list(self.nodepool.getZK(),
+            results = status.request_list(zk)
-                                         format='pretty')
-        elif path == '/request-list.json':
-            output = status.request_list(self.nodepool.getZK(),
-                                         format='json')
         else:
             return None
+
+        output = status.output(results, out_fmt)
+
         return self.cache.put(index, output)
 
     def app(self, request):