Hi,

In October 2018, we (pre)announced that we were working on a consolidated pagure infra for git.centos.org and src.fedoraproject.org. (https://lists.centos.org/pipermail/centos-devel/2018-October/016997.html) We asked feedback from community and one of the remarks we had was about being able to follow commits for all /rpms/*

While there were requests to have that available through pagure API (for people already using the gitblit RPC feature of current https://git.centos.org instance), another idea was to simply send that to a message broker, so that people can just subscribe to that broker on a particular topic and consume the message payloads posted there.

As such MQTT support landed in pagure, we decided to upgrade (both instances) and we have (only at the CentOS side) implemented MQTT notifications to a "public" broker

Example : This dummy commit (specific branch) : https://git.stg.centos.org/rpms/bacula/c/61cd3575ba64b5f7afbf16eeb5c8dea7293...

(automatically replicated to https://src.stg.fedoraproject.org/rpms/bacula/c/61cd3575ba64b5f7afbf16eeb5c8...)

posted the following json message on our MQTT staging broker :

git.stg.centos.org/git.receive {"forced": false, "agent": "arrfab", "repo": {"custom_keys": [], "name": "bacula", "parent": null, "date_modified": "1539692831", "access_users": {"owner": ["centosrcm"], "admin": [], "ticket": [], "commit": []}, "namespace": "rpms", "priorities": {}, "close_status": [], "access_groups": {"admin": [], "commit": [], "ticket": []}, "milestones": {}, "user": {"fullname": "CentOS Sources", "name": "centosrcm"}, "date_created": "1539692831", "fullname": "rpms/bacula", "url_path": "rpms/bacula", "id": 6, "tags": [], "description": " Cross platform network backup for Linux, Unix, Mac and Windows"}, "end_commit": "61cd3575ba64b5f7afbf16eeb5c8dea7293b1241", "branch": "c7-sig-altarch-test", "authors": [{"fullname": "Fabian Arrotin", "name": "arrfab"}], "total_commits": 1, "start_commit": "61cd3575ba64b5f7afbf16eeb5c8dea7293b1241"}

The first part is just the topic, while the message payload is the json

How can you subscribe to that MQTT broker (if you want to automate some workflow) ? The only requirement is to trust our ACO (https://accounts.centos.org) CA cert and also to have your TLS cert from ACO All those steps are done automatically through centos-cert (from centos-packager, see https://wiki.centos.org/HowTos/CentosPackager)

From that point, you can use your MQTT client of choice (mosquitto_sub from mosquitto pkg, or python-paho-mqtt for python client, etc) and point to mqtt.stg.centos.org:8883

Simple example with mosquitto_sub :

mosquitto_sub --cafile ~/.centos-server-ca.cert --cert ~/.centos.cert --key ~/.centos.cert -h mqtt.stg.centos.org -p 8883 -t git.stg.centos.org/# -v

Hope that it helps people willing to get automatic notifications in "real-time" when repositories are created or that there are new commits landing there.

Worth noting that it's still only in staging, but once we have a green light, we should migrate git.centos.org to pagure with the same features set as the one deployed on staging.