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Add initial systemd lifecycle notification support #20

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jcharaoui wants to merge 1 commit into from
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Add initial systemd lifecycle notification support #20

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4 changes: 3 additions & 1 deletion project.clj
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Original file line number Diff line number Diff line change
Expand Up @@ -44,7 +44,9 @@
[puppetlabs/kitchensink nil :exclusions [cheshire]]
[puppetlabs/i18n]
[nrepl/nrepl]
[io.github.clj-kondo/config-slingshot-slingshot "1.0.0"]]
[io.github.clj-kondo/config-slingshot-slingshot "1.0.0"]

[com.kohlschutter.junixsocket/junixsocket-core "2.6.1" :extension "pom"]]

:deploy-repositories [["clojars" {:url "https://clojars.org/repo"
:username :env/CLOJARS_USERNAME
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40 changes: 37 additions & 3 deletions src/puppetlabs/trapperkeeper/internal.clj
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Original file line number Diff line number Diff line change
@@ -1,6 +1,4 @@
(ns puppetlabs.trapperkeeper.internal
(:import (clojure.lang ExceptionInfo IFn IDeref)
(java.lang ArithmeticException NumberFormatException))
(:require [clojure.tools.logging :as log]
[beckon]
[plumbing.graph :as graph]
Expand All @@ -14,7 +12,14 @@
[schema.core :as schema]
[clojure.core.async :as async]
[clojure.core.async.impl.protocols :as async-prot]
[me.raynes.fs :as fs]))
[me.raynes.fs :as fs])
(:import
(clojure.lang ExceptionInfo IFn IDeref)
(java.lang ArithmeticException NumberFormatException)
(java.io File)
(java.net DatagramPacket SocketException)
;; Looks like JDK 16+ support doesn't do SOCK_DGRAM yet
(org.newsclub.net.unix AFUNIXSocketAddress AFUNIXDatagramSocket)))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Schemas
Expand All @@ -28,6 +33,31 @@
;; Private
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; Optional systemd support

(def systemd-notify-socket (System/getenv "NOTIFY_SOCKET"))

(defn maybe-notify-systemd [message]
(when systemd-notify-socket
(with-open [s (AFUNIXDatagramSocket/newInstance)]
(let [buf (.getBytes message "UTF-8")
Comment on lines +42 to +43
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@ekohl ekohl Aug 19, 2025

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The linter shows this:

== Linting puppetlabs.trapperkeeper.internal ==
src/puppetlabs/trapperkeeper/internal.clj:43:17: reflection: call to method getBytes can't be resolved.
src/puppetlabs/trapperkeeper/internal.clj:44:18: reflection: call to java.io.File ctor can't be resolved.
src/puppetlabs/trapperkeeper/internal.clj:158:39: reflection: reference to field error can't be resolved.

Any idea how to solve those? is org.newsclub.net.unix somehow not pulled in project.cli?

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@rlbdv rlbdv Aug 19, 2025

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If trapperkeeper is enforcing "no reflection warnings" globally, then I'd assume those cases just need type hints, e.g. perhaps (.getBytes ^String message "UTF-8"), etc.

addr (-> systemd-notify-socket File. AFUNIXSocketAddress/of)
connected? (try
(.connect s addr)
true
;; Doesn't appear to throw ConnectException
;; for an unmonitored socket.
(catch SocketException _
(log/warn (i18n/trs "Unable to connect to NOTIFY_SOCKET {0}"
(pr-str systemd-notify-socket)))
nil))]
(when connected?
(.send s (DatagramPacket. buf (count buf))))))))

(defn notice-service-ready [] (maybe-notify-systemd "READY=1\n"))
(defn notice-service-reloading [] (maybe-notify-systemd "RELOADING=1\n"))
(defn notice-service-stopping [] (maybe-notify-systemd "STOPPING=1\n"))

;; This is (eww) a global variable that holds a reference to all of the running
;; Trapperkeeper apps in the process. It can be used when connecting via nrepl
;; to allow you to do useful things, and also may be used for other things
Expand Down Expand Up @@ -615,11 +645,13 @@
this)
(a/start [this]
(run-lifecycle-fns app-context s/start "start" ordered-services)
(notice-service-ready)
(inc-restart-counter! this)
this)
(a/stop [this]
(a/stop this false))
(a/stop [this throw?]
(notice-service-stopping)
(let [errors (shutdown! app-context)]
(if (and throw? (seq errors))
(let [msg (i18n/trs "Error during app shutdown!")]
Expand All @@ -628,10 +660,12 @@
this)))
(a/restart [this]
(try
(notice-service-reloading)
(run-lifecycle-fns app-context s/stop "stop" (reverse ordered-services))
(doseq [svc-id (keys services-by-id)] (swap! app-context assoc-in [:service-contexts svc-id] {}))
(run-lifecycle-fns app-context s/init "init" ordered-services)
(run-lifecycle-fns app-context s/start "start" ordered-services)
(notice-service-ready)
(inc-restart-counter! this)
this
(catch Throwable t
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