promtail.clj

(ns monkey.ci.containers.promtail
  "Functions for configuring promtail containers.  This is not a container driver, but
   a utility namespace that is in turn used when pushing build logs to Loki."
  (:require [camel-snake-kebab.core :as csk]
            [clj-yaml.core :as yaml]
            [clojure.walk :as cw]
            [medley.core :as mc]
            [monkey.ci
             [build :as b]
             [runtime :as rt]]))

;; Default promtail settings
(def promtail-image "docker.io/grafana/promtail")
(def promtail-version "2.9.2")

(defn promtail-config
  "Generates config structure that can be passed to promtail.  The structure should
   be converted to yaml in order to be usable by promtail."
  [conf]
  {:server
   {:disable true}
   :positions
   {:filename "/tmp/positions.yaml"}
   :clients
   [(-> {:url (:loki-url conf)
         :tenant-id (:customer-id conf)}
        (mc/assoc-some :bearer-token (:token conf)))]
   :scrape-configs
   [{:job-name "build-logs"
     :static-configs
     (map (fn [path]
            {:labels (-> conf
                         (select-keys [:customer-id :repo-id :build-id :job-id])
                         ;; Add it as a string otherwise case conversion will drop the underscores
                         (assoc "__path__" (str path)))})
          (:paths conf))}]})

(defn ->yaml [conf]
  (letfn [(convert [x]
            (if (keyword? x)
              (csk/->snake_case (name x))
              x))]
    (->> (cw/postwalk
          (fn [obj]
            (if (map-entry? obj)
              [(convert (first obj)) (second obj)]
              obj))
          conf)
         (yaml/generate-string))))

(def yaml-config (comp ->yaml promtail-config))

(defn promtail-container
  "Generates container configuration for promtail.  This is used to push logs to Loki,
   which can then be retrieved later by the client."
  [{:keys [image-url image-tag] :as conf}]
  {:image-url (str (or image-url promtail-image) ":" (or image-tag promtail-version))
   :display-name "promtail"})

(defn rt->config
  "Extracts necessary values from the runtime to create a promtail config map, that
   can be passed to `promtail-config`."
  [rt]
  (letfn [(build-props []
            (zipmap [:customer-id :repo-id :build-id] (b/get-sid rt)))
          (job-props []
            {:job-id (b/rt->job-id rt)})]
    (-> (select-keys (:promtail (rt/config rt)) [:image-url :image-tag :loki-url])
        (merge (build-props)
               (job-props))
        (assoc :token (-> (rt/config rt) :api :token)))))