feat: Enable gzip support for event payloads (#286)

Author: keelerm84

contract-tests/service.py

@@ -70,6 +70,7 @@ def status():
             'secure-mode-hash',
             'tags',
             'migrations',
+            'event-gzip',
             'event-sampling',
             'polling-gzip',
             'inline-context',

ldclient/impl/events/event_processor.py

@@ -12,6 +12,7 @@
 import uuid
 import queue
 import urllib3
+import gzip
 from ldclient.config import Config
 from datetime import timedelta
 from random import Random
@@ -559,19 +560,21 @@ def _post_events_with_retry(
 ):
     hdrs = _headers(config)
     hdrs['Content-Type'] = 'application/json'
+    hdrs['Content-Encoding'] = 'gzip'
     if payload_id:
         hdrs['X-LaunchDarkly-Event-Schema'] = str(__CURRENT_EVENT_SCHEMA__)
         hdrs['X-LaunchDarkly-Payload-ID'] = payload_id
     can_retry = True
     context = "posting %s" % events_description
+    data = gzip.compress(bytes(body, 'utf-8'))
     while True:
         next_action_message = "will retry" if can_retry else "some events were dropped"
         try:
             r = http_client.request(
                 'POST',
                 uri,
                 headers=hdrs,
-                body=body,
+                body=data,
                 timeout=urllib3.Timeout(connect=config.http.connect_timeout, read=config.http.read_timeout),
                 retries=0
             )