From fd5acb85e916f010e063c09ce7a08dc91acd1eda Mon Sep 17 00:00:00 2001
From: Robert Coup <robert@coup.net.nz>
Date: Fri, 27 Oct 2017 09:55:50 +0100
Subject: [PATCH] Suppress duplicate messages for multi-format package uploads.

---
 devpi_slack/main.py | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/devpi_slack/main.py b/devpi_slack/main.py
index 4f77919..f8c241d 100644
--- a/devpi_slack/main.py
+++ b/devpi_slack/main.py
@@ -9,6 +9,11 @@
 from devpi_slack import __version__
 
 
+# simple duplicate message suppression for multiple formats of the same package
+# the hook is triggered once per format upload
+last_message = None
+
+
 def devpiserver_indexconfig_defaults():
     return {"slack_icon": None, "slack_hook": None, "slack_user": None}
 
@@ -22,17 +27,23 @@ def devpiserver_on_upload_sync(log, application_url, stage, project, version):
     if not slack_hook:
         return
 
+    message = "Uploaded {}=={} to {}".format(
+        project,
+        version,
+        application_url
+    )
+    global last_message
+    if message == last_message:
+        log.debug("skipping duplicate Slack notification: %s", message)
+        return
+
     session = new_requests_session(agent=("devpi-slack", __version__))
     try:
         r = session.post(
             slack_hook,
             data={
                 'payload': json.dumps({
-                    "text": "Uploaded {}=={} to {}".format(
-                        project,
-                        version,
-                        application_url
-                    ),
+                    "text": message,
                     "icon_url": slack_icon,
                     "username": slack_user,
                 })
@@ -43,6 +54,7 @@ def devpiserver_on_upload_sync(log, application_url, stage, project, version):
 
     if 200 <= r.status_code < 300:
         log.info("successfully sent Slack notification: %s", slack_hook)
+        last_message = message
     else:
         log.error("%s: failed to send Slack notification: %s", r.status_code,
                   slack_hook)