Add option to file publisher to write json

Change-Id: I21f6f8fca8de1d6b8784e140382d1a1a99398279
Closes-Bug: #1783985

ceilometer/publisher/file.py

@@ -13,6 +13,7 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import json
 import logging
 import logging.handlers
 
@@ -41,12 +42,13 @@ class FilePublisher(publisher.ConfigPublisherBase):
             meters:
                 - "*"
             publishers:
-                - file:///var/test?max_bytes=10000000&backup_count=5
+                - file:///var/test?max_bytes=10000000&backup_count=5&json
 
     File path is required for this publisher to work properly. If max_bytes
     or backup_count is missing, FileHandler will be used to save the metering
     data. If max_bytes and backup_count are present, RotatingFileHandler will
-    be used to save the metering data.
+    be used to save the metering data. The json argument is used to explicitely
+    ask ceilometer to write json into the file.
     """
 
     def __init__(self, conf, parsed_url):
@@ -61,9 +63,13 @@ class FilePublisher(publisher.ConfigPublisherBase):
         rfh = None
         max_bytes = 0
         backup_count = 0
+        self.output_json = None
         # Handling other configuration options in the query string
         if parsed_url.query:
-            params = urlparse.parse_qs(parsed_url.query)
+            params = urlparse.parse_qs(parsed_url.query,
+                                       keep_blank_values=True)
+            if "json" in params:
+                self.output_json = True
             if params.get('max_bytes') and params.get('backup_count'):
                 try:
                     max_bytes = int(params.get('max_bytes')[0])
@@ -90,7 +96,10 @@ class FilePublisher(publisher.ConfigPublisherBase):
         """
         if self.publisher_logger:
             for sample in samples:
-                self.publisher_logger.info(sample.as_dict())
+                if self.output_json:
+                    self.publisher_logger.info(json.dumps(sample.as_dict()))
+                else:
+                    self.publisher_logger.info(sample.as_dict())
 
     def publish_events(self, events):
         """Send an event message for publishing
@@ -99,4 +108,7 @@ class FilePublisher(publisher.ConfigPublisherBase):
         """
         if self.publisher_logger:
             for event in events:
-                self.publisher_logger.info(event.as_dict())
+                if self.output_json:
+                    self.publisher_logger.info(json.dumps(event.as_dict()))
+                else:
+                    self.publisher_logger.info(event.as_dict())

ceilometer/tests/unit/publisher/test_file.py

@@ -16,6 +16,7 @@
 """
 
 import datetime
+import json
 import logging.handlers
 import os
 import tempfile
@@ -120,3 +121,32 @@ class TestFilePublisher(base.BaseTestCase):
         publisher.publish_samples(self.test_data)
 
         self.assertIsNone(publisher.publisher_logger)
+
+    def test_file_publisher_json(self):
+        tempdir = tempfile.mkdtemp()
+        name = '%s/log_file_json' % tempdir
+        parsed_url = netutils.urlsplit('file://%s?json' % name)
+
+        publisher = file.FilePublisher(self.CONF, parsed_url)
+        publisher.publish_samples(self.test_data)
+
+        handler = publisher.publisher_logger.handlers[0]
+        self.assertIsInstance(handler,
+                              logging.handlers.RotatingFileHandler)
+        self.assertEqual([0, name, 0], [handler.maxBytes,
+                                        handler.baseFilename,
+                                        handler.backupCount])
+        self.assertTrue(os.path.exists(name))
+        with open(name, 'r') as f:
+            content = f.readlines()
+
+        self.assertEqual(len(self.test_data), len(content))
+        for index, line in enumerate(content):
+            try:
+                json_data = json.loads(line)
+            except ValueError:
+                self.fail("File written is not valid json")
+            self.assertEqual(self.test_data[index].id,
+                             json_data['id'])
+            self.assertEqual(self.test_data[index].timestamp,
+                             json_data['timestamp'])

doc/source/admin/telemetry-data-pipelines.rst

@@ -247,6 +247,10 @@ The following options are available for the ``file`` publisher:
     the newest data is always the one that is specified without any
     extensions.
 
+``json``
+    If this option is present, will force ceilometer to write json format
+    into the file.
+
 http
 ````
 

releasenotes/notes/add-json-output-to-file-publisher-786380cb7e21b56b.yaml

@@ -0,0 +1,5 @@
+---
+features:
+  - >
+    Add new json output option for the existing file publisher.
+