loki-alloy-example.yaml

# Grafana Alloy pipeline reference — ship serialmonitor pod logs to Loki
#
# This is NOT deployed by this repo. Add it to your Alloy config or Promtail
# pipeline config in your observability stack.
#
# serialmonitor emits structured JSON logs to stdout, e.g.:
#   {"time":"...","level":"INFO","port":"arduino","device":"/dev/ttyUSB0","msg":"received","data":"..."}
#
# The pipeline below:
#   1. Discovers serialmonitor pods via Kubernetes API
#   2. Parses the JSON log lines
#   3. Promotes "port", "level", and "device" fields to Loki labels
#   4. Ships to your Loki instance
#
# With this config you can query in Grafana:
#   {app="serialmonitor", port="arduino"} | json
#   {app="serialmonitor"} | json | level="ERROR"

# ── Alloy (River syntax) ──────────────────────────────────────
#
# discovery.kubernetes "serialmonitor_pods" {
#   role = "pod"
#   namespaces { names = ["default"] }   # adjust to your namespace
#   selectors {
#     role  = "pod"
#     label = "app.kubernetes.io/name=serialmonitor"
#   }
# }
#
# loki.source.kubernetes "serialmonitor" {
#   targets    = discovery.kubernetes.serialmonitor_pods.targets
#   forward_to = [loki.process.serialmonitor_json.receiver]
# }
#
# loki.process "serialmonitor_json" {
#   stage.json {
#     expressions = {
#       port   = "port",
#       level  = "level",
#       device = "device",
#     }
#   }
#   stage.labels {
#     values = {
#       port   = "",
#       level  = "",
#       device = "",
#     }
#   }
#   forward_to = [loki.write.default.receiver]
# }

# ── Promtail (YAML syntax, if you use Promtail instead of Alloy) ─────────────
#
# scrape_configs:
#   - job_name: serialmonitor
#     kubernetes_sd_configs:
#       - role: pod
#     relabel_configs:
#       - source_labels: [__meta_kubernetes_pod_label_app_kubernetes_io_name]
#         action: keep
#         regex: serialmonitor
#       - source_labels: [__meta_kubernetes_pod_name]
#         target_label: pod
#       - source_labels: [__meta_kubernetes_namespace]
#         target_label: namespace
#     pipeline_stages:
#       - json:
#           expressions:
#             port:   port
#             level:  level
#             device: device
#             output: data
#       - labels:
#           port:
#           level:
#           device:
#       - output:
#           source: output