feat (chart): add Langfuse retention management with ClickHouse TTL and hard delete

infrastructure/README.md

@@ -188,6 +188,31 @@ For local development you can let Tilt generate Langfuse init secrets automatica
 - Tilt runs Kustomize on `infrastructure/kustomize/langfuse` and applies the resulting `langfuse-init-secrets` (hash disabled) before Helm resources.
 - This is dev-only. For production, create/manage secrets with your secret manager and set `secretKeyRef.name` in `values.yaml` to your managed secret.
 
+**Langfuse Trace Retention via ClickHouse TTL (without Enterprise)**  
+If you want automatic deletion (for example after 1 year) without Langfuse Enterprise data-retention management, enable the chart-level retention CronJob:
+
+```yaml
+langfuseRetention:
+  enabled: true
+  retentionDays: 365
+  schedule: "15 */6 * * *"
+  hardDelete:
+    enabled: true
+    schedule: "30 3 * * *"
+    mutationSync: 0
+  clickhouse:
+    database: "default"
+    onCluster: true
+    clusterName: "default"
+```
+
+Notes:
+- ClickHouse connection/auth for retention jobs is taken from `langfuse.clickhouse.*` (same source as Langfuse itself).
+- The CronJob applies idempotent `ALTER TABLE ... MODIFY TTL` statements on Langfuse tables (`traces`, `observations`, `scores`).
+- If `hardDelete.enabled=true`, an additional CronJob executes deterministic `ALTER TABLE ... DELETE WHERE ...` mutations.
+- Deletion is then handled by ClickHouse background merges (not instant at the exact cutoff timestamp).
+- Avoid applying TTL blindly to every table. Some tables are views/metadata and should not be retention-trimmed.
+
 ### 1.2 Qdrant
 
 The deployment of the Qdrant can be disabled by setting the following value in the helm-chart:

infrastructure/rag/templates/_helpers.tpl

@@ -78,3 +78,34 @@
 {{- toYaml $data -}}
 {{- end }}
 {{- end -}}
+
+{{/* Shared ClickHouse env for Langfuse retention CronJobs. */}}
+{{- define "rag.langfuseRetentionClickhouseEnv" -}}
+{{- $chHost := default (printf "%s-clickhouse" .Release.Name | trunc 63 | trimSuffix "-") .Values.langfuse.clickhouse.host -}}
+{{- $chUser := default "default" .Values.langfuse.clickhouse.auth.username -}}
+{{- $chPasswordSecretName := default (printf "%s-clickhouse" .Release.Name | trunc 63 | trimSuffix "-") .Values.langfuse.clickhouse.auth.existingSecret -}}
+{{- $chPasswordKey := .Values.langfuse.clickhouse.auth.existingSecretKey -}}
+{{- $chNativePort := default 9000 .Values.langfuse.clickhouse.nativePort -}}
+- name: CLICKHOUSE_HOST
+  value: {{ $chHost | quote }}
+- name: CLICKHOUSE_PORT
+  value: {{ $chNativePort | quote }}
+- name: CLICKHOUSE_USER
+  value: {{ $chUser | quote }}
+- name: CLICKHOUSE_DATABASE
+  value: {{ .Values.langfuseRetention.clickhouse.database | quote }}
+- name: CLICKHOUSE_ON_CLUSTER
+  value: {{ ternary "true" "false" .Values.langfuseRetention.clickhouse.onCluster | quote }}
+- name: CLICKHOUSE_CLUSTER_NAME
+  value: {{ .Values.langfuseRetention.clickhouse.clusterName | quote }}
+- name: RETENTION_DAYS
+  value: {{ .Values.langfuseRetention.retentionDays | quote }}
+- name: CLICKHOUSE_PASSWORD_LITERAL
+  value: {{ .Values.langfuse.clickhouse.auth.password | quote }}
+- name: CLICKHOUSE_PASSWORD
+  valueFrom:
+    secretKeyRef:
+      name: {{ $chPasswordSecretName | quote }}
+      key: {{ default "CLICKHOUSE_PASSWORD" $chPasswordKey | quote }}
+      optional: true
+{{- end -}}

infrastructure/rag/templates/langfuse-retention-cronjob.yaml

@@ -0,0 +1,70 @@
+{{- if and .Values.features.langfuse.enabled .Values.langfuseRetention.enabled }}
+{{- $retentionImage := printf "%s:%s" .Values.langfuseRetention.image.repository .Values.langfuseRetention.image.tag -}}
+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: {{ printf "%s-langfuse-retention" .Release.Name | trunc 63 | trimSuffix "-" }}
+  labels:
+    app.kubernetes.io/name: rag
+    app.kubernetes.io/instance: {{ .Release.Name }}
+spec:
+  schedule: {{ .Values.langfuseRetention.schedule | quote }}
+  concurrencyPolicy: Forbid
+  successfulJobsHistoryLimit: 1
+  failedJobsHistoryLimit: 3
+  jobTemplate:
+    spec:
+      template:
+        metadata:
+          labels:
+            app.kubernetes.io/name: rag
+            app.kubernetes.io/instance: {{ .Release.Name }}
+        spec:
+          restartPolicy: OnFailure
+          containers:
+            - name: apply-clickhouse-ttl
+              image: {{ $retentionImage | quote }}
+              imagePullPolicy: {{ .Values.langfuseRetention.image.pullPolicy | quote }}
+              command:
+                - /bin/bash
+                - -ec
+              args:
+                - |
+                  set -euo pipefail
+
+                  PASSWORD="${CLICKHOUSE_PASSWORD:-}"
+                  if [ -z "${PASSWORD}" ]; then
+                    PASSWORD="${CLICKHOUSE_PASSWORD_LITERAL:-}"
+                  fi
+
+                  if [ -z "${PASSWORD}" ]; then
+                    echo "No ClickHouse password found. Check langfuse.clickhouse.auth settings and secret."
+                    exit 1
+                  fi
+
+                  ON_CLUSTER_CLAUSE=""
+                  if [ "${CLICKHOUSE_ON_CLUSTER}" = "true" ]; then
+                    ON_CLUSTER_CLAUSE=" ON CLUSTER ${CLICKHOUSE_CLUSTER_NAME}"
+                  fi
+
+                  TABLE_ROWS="$(cat <<'EOF_TABLES'
+                  {{- range .Values.langfuseRetention.clickhouse.tables }}
+                  {{ .name }}	{{ .timestampColumn }}
+                  {{- end }}
+                  EOF_TABLES
+                  )"
+
+                  while IFS=$'\t' read -r table ts_col; do
+                    [ -z "${table}" ] && continue
+
+                    echo "Applying TTL=${RETENTION_DAYS}d to ${CLICKHOUSE_DATABASE}.${table} (${ts_col})"
+                    clickhouse-client \
+                      --host "${CLICKHOUSE_HOST}" \
+                      --port "${CLICKHOUSE_PORT}" \
+                      --user "${CLICKHOUSE_USER}" \
+                      --password "${PASSWORD}" \
+                      --query "ALTER TABLE ${CLICKHOUSE_DATABASE}.${table}${ON_CLUSTER_CLAUSE} MODIFY TTL toDateTime(${ts_col}) + toIntervalDay(${RETENTION_DAYS})"
+                  done <<< "${TABLE_ROWS}"
+              env:
+{{ include "rag.langfuseRetentionClickhouseEnv" . | nindent 16 }}
+{{- end }}

infrastructure/rag/templates/langfuse-retention-hard-delete-cronjob.yaml

@@ -0,0 +1,74 @@
+{{- if and .Values.features.langfuse.enabled .Values.langfuseRetention.hardDelete.enabled }}
+{{- $retentionImage := printf "%s:%s" .Values.langfuseRetention.image.repository .Values.langfuseRetention.image.tag -}}
+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: {{ printf "%s-langfuse-retention-delete" .Release.Name | trunc 63 | trimSuffix "-" }}
+  labels:
+    app.kubernetes.io/name: rag
+    app.kubernetes.io/instance: {{ .Release.Name }}
+spec:
+  schedule: {{ .Values.langfuseRetention.hardDelete.schedule | quote }}
+  concurrencyPolicy: Forbid
+  successfulJobsHistoryLimit: 1
+  failedJobsHistoryLimit: 3
+  jobTemplate:
+    spec:
+      template:
+        metadata:
+          labels:
+            app.kubernetes.io/name: rag
+            app.kubernetes.io/instance: {{ .Release.Name }}
+        spec:
+          restartPolicy: OnFailure
+          containers:
+            - name: delete-expired-rows
+              image: {{ $retentionImage | quote }}
+              imagePullPolicy: {{ .Values.langfuseRetention.image.pullPolicy | quote }}
+              command:
+                - /bin/bash
+                - -ec
+              args:
+                - |
+                  set -euo pipefail
+
+                  PASSWORD="${CLICKHOUSE_PASSWORD:-}"
+                  if [ -z "${PASSWORD}" ]; then
+                    PASSWORD="${CLICKHOUSE_PASSWORD_LITERAL:-}"
+                  fi
+
+                  if [ -z "${PASSWORD}" ]; then
+                    echo "No ClickHouse password found. Check langfuse.clickhouse.auth settings and secret."
+                    exit 1
+                  fi
+
+                  ON_CLUSTER_CLAUSE=""
+                  if [ "${CLICKHOUSE_ON_CLUSTER}" = "true" ]; then
+                    ON_CLUSTER_CLAUSE=" ON CLUSTER ${CLICKHOUSE_CLUSTER_NAME}"
+                  fi
+
+                  TABLE_ROWS="$(cat <<'EOF_TABLES'
+                  {{- range .Values.langfuseRetention.clickhouse.tables }}
+                  {{ .name }}	{{ .timestampColumn }}
+                  {{- end }}
+                  EOF_TABLES
+                  )"
+
+                  CUTOFF_UNIX="$(( $(date -u +%s) - RETENTION_DAYS * 86400 ))"
+
+                  while IFS=$'\t' read -r table ts_col; do
+                    [ -z "${table}" ] && continue
+
+                    echo "Deleting rows older than ${RETENTION_DAYS}d from ${CLICKHOUSE_DATABASE}.${table} (${ts_col})"
+                    clickhouse-client \
+                      --host "${CLICKHOUSE_HOST}" \
+                      --port "${CLICKHOUSE_PORT}" \
+                      --user "${CLICKHOUSE_USER}" \
+                      --password "${PASSWORD}" \
+                      --query "ALTER TABLE ${CLICKHOUSE_DATABASE}.${table}${ON_CLUSTER_CLAUSE} DELETE WHERE toDateTime(${ts_col}) < toDateTime(${CUTOFF_UNIX}) SETTINGS mutations_sync = ${MUTATION_SYNC}"
+                  done <<< "${TABLE_ROWS}"
+              env:
+                - name: MUTATION_SYNC
+                  value: {{ .Values.langfuseRetention.hardDelete.mutationSync | quote }}
+{{ include "rag.langfuseRetentionClickhouseEnv" . | nindent 16 }}
+{{- end }}

infrastructure/rag/values.yaml

@@ -734,6 +734,37 @@ langfuse:
           name: ""
       key: ""
 
+# Optional: enforce a ClickHouse TTL for Langfuse traces without Enterprise data retention management.
+# This runs as a CronJob and applies idempotent ALTER TABLE ... MODIFY TTL commands.
+langfuseRetention:
+  enabled: false
+  retentionDays: 365
+  schedule: "15 */6 * * *"
+  # Optional deterministic deletion in addition to TTL.
+  # Uses ALTER TABLE ... DELETE WHERE ... and can run nightly.
+  hardDelete:
+    enabled: false
+    schedule: "30 3 * * *"
+    # ClickHouse mutations_sync setting:
+    # 0 = async (default), 1 = wait for local completion, 2 = wait for all replicas.
+    mutationSync: 0
+  image:
+    repository: "bitnamilegacy/clickhouse"
+    tag: "25.2.1-debian-12-r0"
+    pullPolicy: IfNotPresent
+  clickhouse:
+    # Connection/auth are taken from langfuse.clickhouse.*.
+    database: "default"
+    onCluster: true
+    clusterName: "default"
+    tables:
+      - name: "traces"
+        timestampColumn: "timestamp"
+      - name: "observations"
+        timestampColumn: "event_ts"
+      - name: "scores"
+        timestampColumn: "timestamp"
+
 minio:
   image:
     repository: bitnamilegacy/minio