# GoChat Fluentd Configuration
# Reference: Chatwoot logging infrastructure pattern
# Collects structured JSON logs from GoChat containers and sends to Elasticsearch
#
# Deployment: deploy/fluentd/ — apply as ConfigMap + Deployment in K8s
# Usage: kubectl apply -k deploy/fluentd/

# ---- Source: tail GoChat container logs ----
<source>
  @type tail
  path /var/log/containers/gochat*.log
  pos_file /var/log/fluentd-gochat.pos
  tag gochat.app
  read_from_head true
  <parse>
    @type json
    time_key timestamp
    time_format %Y-%m-%dT%H:%M:%S.%NZ
    keep_time_key true
  </parse>
</source>

# ---- Source: tail GoChat worker logs ----
<source>
  @type tail
  path /var/log/containers/gochat-worker*.log
  pos_file /var/log/fluentd-gochat-worker.pos
  tag gochat.worker
  read_from_head true
  <parse>
    @type json
    time_key timestamp
    time_format %Y-%m-%dT%H:%M:%S.%NZ
    keep_time_key true
  </parse>
</source>

# ---- Filter: Add Kubernetes metadata (pod name, namespace, labels) ----
<filter gochat.**>
  @type kubernetes_metadata
  @id filter_kube_metadata
</filter>

# ---- Filter: Parse log level for Elasticsearch routing ----
<filter gochat.**>
  @type record_transformer
  <record>
    # Add searchable fields from GoChat structured logs
    log_level ${record["level"]}
    component ${record["component"]}
    environment ${record["GOCHAT_ENV"]}
    # Flatten error details for Kibana searching
    error_message ${record["error"]}
  </record>
</filter>

# ---- Output: Elasticsearch (primary) ----
<match gochat.**>
  @type elasticsearch
  @id out_es_gochat
  @log_level info

  # Elasticsearch connection
  host ${ELASTICSEARCH_HOST}
  port ${ELASTICSEARCH_PORT}
  scheme https
  ssl_version TLSv1_2
  # Authentication
  user ${ELASTICSEARCH_USER}
  password ${ELASTICSEARCH_PASSWORD}

  # Index naming: gochat-YYYY.MM.dd (daily rotation)
  index_name gochat
  template_name gochat
  template_file /fluentd/etc/gochat-index-template.json

  # ILM (Index Lifecycle Management) for automatic rotation
  ilm_policy_name gochat-log-policy
  ilm_policy_id gochat-log-policy

  # Bulk indexing for performance
  bulk_request_timeout 10s
  flush_interval 5s
  retry_max_interval 30s
  retry_forever true

  # Buffer configuration (disk-backed for reliability)
  <buffer>
    @type file
    path /var/log/fluentd/buffers/gochat
    flush_interval 5s
    flush_thread_interval 1s
    flush_mode lazy
    retry_type exponential_backoff
    retry_forever true
    overflow_action block
    chunk_limit_size 16M
    total_limit_size 8G
  </buffer>

  # Time-based index naming
  time_key timestamp
  time_slice_format %Y.%m.%d
  time_slice_wait 10m
</match>

# ---- Output: Stdout for debugging ----
<match gochat.debug.**>
  @type stdout
</match>