From bdf879e15a356f446b0667467b4b411bd0b7c83b Mon Sep 17 00:00:00 2001
From: Florent Tapponnier <contact@mobula.io>
Date: Wed, 8 Jul 2026 23:43:20 +0200
Subject: [PATCH] =?UTF-8?q?alertmanager:=20split=20routing=20=E2=80=94=20a?=
 =?UTF-8?q?gg-latency=20stays=20on=20the=20relay=20channel,=20everything?=
 =?UTF-8?q?=20else=20to=20the=20dedicated=20OCB=20Slack=20webhook=20(env-i?=
 =?UTF-8?q?njected)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../alertmanager/alertmanager.yml.tmpl         | 18 +++++++++++++++++-
 .../monitoring/alertmanager/entrypoint.sh      |  7 ++++++-
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/infrastructure/monitoring/alertmanager/alertmanager.yml.tmpl b/infrastructure/monitoring/alertmanager/alertmanager.yml.tmpl
index 49d6d7ab..fd0f9799 100644
--- a/infrastructure/monitoring/alertmanager/alertmanager.yml.tmpl
+++ b/infrastructure/monitoring/alertmanager/alertmanager.yml.tmpl
@@ -6,9 +6,25 @@ route:
   group_wait: 10s
   group_interval: 30s
   repeat_interval: 5m
-  receiver: 'slack-webhook'
+  # Default: dedicated OCB Slack channel (direct incoming webhook).
+  receiver: 'slack-direct'
+  routes:
+    # Aggregator-latency alerts keep their historical channel via the
+    # internal relay (#alerting-aggregator-latency).
+    - matchers:
+        - app = "aggregator_latency_monitor"
+      receiver: 'slack-webhook'
 
 receivers:
+  - name: 'slack-direct'
+    slack_configs:
+      - api_url: '${SLACK_WEBHOOK_URL}'
+        send_resolved: true
+        title: '{{ if eq .Status "firing" }}⚠️{{ else }}✅{{ end }} {{ .CommonLabels.alertname }}'
+        text: |
+          {{ range .Alerts }}*{{ .Annotations.summary }}*
+          {{ .Annotations.description }}
+          {{ end }}
   - name: 'slack-webhook'
     webhook_configs:
       - url: '${ALERT_WEBHOOK_URL}'
diff --git a/infrastructure/monitoring/alertmanager/entrypoint.sh b/infrastructure/monitoring/alertmanager/entrypoint.sh
index 2c149d01..2f5afee8 100755
--- a/infrastructure/monitoring/alertmanager/entrypoint.sh
+++ b/infrastructure/monitoring/alertmanager/entrypoint.sh
@@ -12,7 +12,12 @@ if [ -z "$ALERT_WEBHOOK_URL" ]; then
   echo "WARNING: ALERT_WEBHOOK_URL not set — alerts will be dropped by the webhook receiver."
 fi
 
-sed "s|\${ALERT_WEBHOOK_URL}|${ALERT_WEBHOOK_URL}|g" \
+if [ -z "$SLACK_WEBHOOK_URL" ]; then
+  echo "WARNING: SLACK_WEBHOOK_URL not set — default receiver will drop alerts."
+fi
+
+sed -e "s|\${ALERT_WEBHOOK_URL}|${ALERT_WEBHOOK_URL}|g" \
+    -e "s|\${SLACK_WEBHOOK_URL}|${SLACK_WEBHOOK_URL}|g" \
   /etc/alertmanager/alertmanager.yml.tmpl \
   > /etc/alertmanager/alertmanager.yml