pisto is a simplistic formalization of the lifecycle of stateful systems. Removes a lot of the pain related to debugging a system of many simple services as long as they can be run in a single JVM.
Getting Started
A system of, for example, simple services can be expressed in a namespace like this.
(ns system.core
(:require [pisto.core :as pisto])
(:require [clojure.tools.namespace.repl :as tns])
(:require [wildrank.site :as wildrank])
(:require [annagreta.site :as annagreta]))
;all system state (at least the state needed in order to tear down the system) will be accessible through this var after system startup
(defonce system {:start-order [:annagreta :wildrank]
:parts {:annagreta {:config {:db {:uri "datomic:mem://auth"}
:uri {:port 8060}}}
:wildrank {:config {:uri {:port 8080}}}}})
(defn restart [] (alter-var-root #'system #(pisto/restart-parts %)))
(defn start [] (alter-var-root #'system #(pisto/start-parts %)))
(defn stop [] (alter-var-root #'system #(pisto/stop-parts %))
(alter-var-root #'system #(pisto/clear-all-stateful-info %)))
;These should be mapped to some keyboard shortcuts in the dev environment
(defn reload-and-restart [] (stop) (tns/refresh-all :after 'system.core/start))
(defn update-and-restart [] (stop) (tns/refresh :after 'system.core/start))It is then up to each part/sub system to ensure it can be started and stopped:
(ns annagreta.site
(:require [net.cgrand.moustache :as moustache])
(:require [pisto.core :as pisto]))
(defonce state nil)
(def routes (-> (moustache/app ["hello-world-resource"] (moustache/app :get (fn [req] {:body "hello world!!!"})))
(defmethod pisto/start-part :annagreta [[type {:keys [config]}]]
(let [db-uri (:uri (:db config))
site-jetty-port (:port (:uri config))]
(alter-var-root #'state
(fn [_]
{:auth-db-conn (when db-uri (connect-and-init! db-uri))
:site-jetty (when site-jetty-port (run-jetty #'routes {:port site-jetty-port :join? false}))}))))
(defmethod pisto/stop-part :annagreta [[type part]]
(let [db-uri (:uri (:db (:config part)))
site-jetty (:site-jetty (:state part))]
(when site-jetty (.stop site-jetty))
(d/delete-database db-uri)))Project Maturity
Developed primarily for my personal use. API's can change without notice.
Artifacts
Pisto on Clojars. If you are using Maven, add the following repository
definition to your pom.xml:
<repository>
<id>clojars.org</id>
<url>http://clojars.org/repo</url>
</repository>With Leiningen: [pisto "0.1"]
Major dependencies
- Clojure (version 1.5.1)
License
Copyright (C) 2013 Marcus Holst
Licensed under the Eclipse Public License v1.0 (the same as Clojure).
