Add ClickHouse Support

project.clj

@@ -107,6 +107,7 @@
                    :kafka :kafka
                    :pushover :pushover
                    :msteams :msteams
+                   :clickhouse :clickhouse
                    :all (fn [_] true)}
 ;;  :javac-options     ["-target" "1.6" "-source" "1.6"]
   :java-source-paths ["src/riemann/"]

src/riemann/clickhouse.clj

@@ -0,0 +1,88 @@
+(ns riemann.clickhouse
+  "Forwards riemann events to ClickHouse."
+  (:require [clojure.string :as str]
+            [clj-http.client :as http]))
+
+(defn generate-tags
+  [tags]
+  (str/replace tags #"\"" "'"))
+
+(defn generate-datapoint
+  "Accepts riemann event and converts it into clickhouse datapoint."
+  [event]
+  (let [timestamp (long (:time event))
+        host      (:host event)
+        metric    (:metric event)
+        service   (:service event)
+        tags      (generate-tags (:tags event))]
+    (when (and host metric service)
+      (str timestamp "," host "," service "," metric "," tags \newline))))
+
+(defn generate-datapoint-batch
+  "Accepts riemann events and converts it into clickhouse datapoint batch."
+  [events]
+  (let [processed-events (map generate-datapoint events)]
+    (str/join "" processed-events)))
+
+(defn generate-url
+  "Generates the URL to which datapoint should be posted."
+  [opts]
+  (let [scheme   (:scheme opts)
+        host     (:host opts)
+        port     (:port opts)
+        database (:database opts)
+        table    (:table opts)]
+    (str scheme host ":" port "/?query=INSERT%20INTO%20" database "." table "%20FORMAT%20CSV")))
+
+(defn post-datapoint
+  "Post the riemann event as clickhouse datapoint."
+  [url datapoint]
+  (let [http-options {:body                  datapoint
+                      :content-type          :csv
+                      :conn-timeout          5000
+                      :socket-timeout        5000
+                      :throw-entire-message? true}]
+    (http/post url http-options)))
+
+(defn clickhouse
+  "Returns a function which accepts an event and sends it to clickhouse.
+
+   Usage:
+
+   (batch 10000 5 (clickhouse {:host \"play.clickhouse.com\"}))
+
+   Options:
+
+   - `:scheme`         ClickHouse URL Scheme (default: \"http://\")
+   - `:host`           ClickHouse Server IP (default: \"localhost\")
+   - `:port`           ClickHouse Server Port (default: 8123)
+   - `:database`       ClickHouse Database Name (default: \"default\")
+   - `:table`          ClickHouse Table Name (default: \"riemann\")
+
+   You need to first create a clickhouse table:
+
+   CREATE TABLE default.riemann
+   (
+      `timestamp` DateTime,
+      `host` String,
+      `service` String,
+      `metric` Float32,
+      `tags` Array(String)
+   )
+   ENGINE = MergeTree
+   PARTITION BY toYYYYMM(timestamp)
+   ORDER BY (timestamp, host, service)
+   SETTINGS index_granularity = 8192;
+  "
+  [opts]
+  (let [opts (merge {:scheme "http://"
+                     :host "localhost"
+                     :port 8123
+                     :database "default"
+                     :table "riemann"}
+                    opts)]
+    (fn [events]
+      (let [url (generate-url opts)
+            datapoint (generate-datapoint-batch events)]
+        (if-not (nil? datapoint)
+          (post-datapoint url datapoint))))))

src/riemann/config.clj

@@ -6,6 +6,7 @@
   (:import (java.io File))
   (:require [riemann [boundary    :refer [boundary]]
                      [client      :refer [udp-client tcp-client multi-client]]
+                     [clickhouse  :refer [clickhouse]]
                      [cloudwatch  :refer [cloudwatch]]
                      [common      :as common :refer [event]]
                      [core        :as core]

test/riemann/clickhouse_test.clj

@@ -0,0 +1,30 @@
+(ns riemann.clickhouse-test
+  (:use riemann.clickhouse
+        [riemann.time :only [unix-time]]
+        clojure.test)
+  (:require [riemann.logging :as logging]))
+
+(logging/init)
+
+(deftest ^:clickhouse ^:integration clickhouse-test
+  (let [k (clickhouse {:block-start true})]
+    (k {:host "riemann.local"
+        :service "clickhouse test"
+        :state "ok"
+        :description "all clear, uh, situation normal"
+        :metric -2
+        :time (unix-time)}))
+
+  (let [k (clickhouse {:block-start true})]
+    (k {:service "clickhouse test"
+        :state "ok"
+        :description "all clear, uh, situation normal"
+        :metric 3.14159
+        :time (unix-time)}))
+
+  (let [k (clickhouse {:block-start true})]
+    (k {:host "no-service.riemann.local"
+        :state "ok"
+        :description "missing service, not transmitted"
+        :metric 4
+        :time (unix-time)})))