Add Python PubSub pipeline for processing gcloud logs (#10)

* Add Python PubSub pipeline for processing gcloud logs

* Refactoring

* Refactoring

* Refactoring

Python/pubsub/gcloud_logs_filter_with_dlq.py

@@ -0,0 +1,133 @@
+#  Copyright 2023 Google LLC
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+import logging
+import json
+
+import apache_beam as beam
+from apache_beam import DoFn
+from apache_beam import Filter
+from apache_beam import Map
+from apache_beam import ParDo
+from apache_beam.io import ReadFromPubSub
+from apache_beam.io import WriteToPubSub
+from apache_beam.options.pipeline_options import PipelineOptions
+
+
+PROCESSED_TAG = "processed"
+UNPROCESSED_TAG = "unprocessed"
+
+
+class PubSubOptions(PipelineOptions):
+
+    @classmethod
+    def _add_argparse_args(cls, parser):
+        parser.add_argument(
+            "--input_topic",
+            default="projects/your-project/topics/your-input-test",
+            help="Input PubSub topic")
+        parser.add_argument(
+            "--output_topic",
+            default="projects/your-project/topics/your-output-test",
+            help="Output PubSub topic")
+        parser.add_argument(
+            "--dlq_topic",
+            default="projects/your-project/topics/your-dlq-test",
+            help="Dead Letter Queue PubSub topic")
+
+
+def run():
+    """
+    This Apache Beam pipeline processes log messages from a Google Cloud Pub/Sub topic.
+    The expected data format follows the standard Google Cloud log format,
+    which can be achieved by routing logs to a Pub/Sub topic via https://console.cloud.google.com/logs/router.
+
+    It performs the following steps:
+    1. Input Configuration:
+        - Reads messages from the specified input Pub/Sub topic.
+
+    2. Message Parsing:
+        - Parses each message as a JSON dictionary.
+
+    3. Message Splitting:
+        - Divides messages into two categories:
+        a. PROCESSED (contain both 'severity' and 'jsonPayload' fields)
+        b. UNPROCESSED (missing one or both of these fields).
+
+    4. Severity Filtering:
+        - For PROCESSED messages, filters out those with severity other than "ERROR".
+
+    5. Data Transformation:
+        - Extracts timestamp and message content from the 'jsonPayload' field for PROCESSED messages.
+
+    6. Output Handling:
+        - Writes transformed PROCESSED messages to a specified output Pub/Sub topic.
+        - Sends UNPROCESSED messages to a Dead Letter Queue (DLQ) topic.
+    """
+
+    options = PubSubOptions(streaming=True)
+
+    with beam.Pipeline(options=options) as p:
+        split_result = (p | "Read from PubSub" >> ReadFromPubSub(topic=options.input_topic)
+                            | "Parse JSON" >> Map(lambda msg: json.loads(msg))
+                            | "Split Messages" >> ParDo(SplitMessages()).with_outputs(UNPROCESSED_TAG, PROCESSED_TAG))
+
+        # Filter processed messages and write to output topic
+        (split_result[PROCESSED_TAG]
+         | "Filter by Severity" >> Filter(filter_by_severity)
+         | "Map to PubsubMessage for output" >> Map(to_pubsub_message_for_output)
+         | "Write to PubSub" >> WriteToPubSub(options.output_topic, with_attributes=True))
+
+        # Write unprocessed messages to DLQ
+        (split_result[UNPROCESSED_TAG]
+         | "Map to PubsubMessage for DLQ" >> Map(to_pubsub_message_for_dlq)
+         | "Write to DLQ" >> WriteToPubSub(options.dlq_topic, with_attributes=True))
+
+
+class SplitMessages(DoFn):
+    def process(self, element):
+        from apache_beam.pvalue import TaggedOutput
+
+        if ('severity' in element) & ('jsonPayload' in element):
+            yield TaggedOutput(PROCESSED_TAG, element)
+        else:
+            yield TaggedOutput(UNPROCESSED_TAG, element)
+
+
+def filter_by_severity(log):
+    # Filter logs by severity level (only process logs with severity "ERROR")
+    return log.get("severity").upper() == "ERROR"
+
+
+def to_pubsub_message_for_dlq(msg):
+    from apache_beam.io import PubsubMessage
+
+    return PubsubMessage(data=bytes(json.dumps(msg), "utf-8"), attributes=None)
+
+
+def to_pubsub_message_for_output(log):
+    from apache_beam.io import PubsubMessage
+
+    # Example transformation: Extract relevant information from the log
+    transformed_data = {
+        "timestamp": log.get("timestamp"),
+        "message": log.get("jsonPayload").get("message")
+    }
+    data = bytes(f"Error log message: {transformed_data['message']} [{transformed_data['timestamp']}]", "utf-8")
+    return PubsubMessage(data=data, attributes=transformed_data)
+
+
+if __name__ == "__main__":
+    logging.getLogger().setLevel(logging.INFO)
+    run()