self update (work in progress)

README.md

@@ -177,7 +177,8 @@ You can also use the convenience functions which use the global `*provider*`.
 
 The provider is initialized with
 [Stuart Sierra's Component](https://github.com/stuartsierra/component)
-library, therefore if you want you can include the provider component in your system map:
+library, therefore if you want you can include the provider component
+in your system map:
 
 ```Clojure
 (defn your-system [config-options]

project.clj

@@ -9,7 +9,8 @@
                  [com.maxmind.geoip2/geoip2 "2.3.1"]
                  [clj-http "1.1.2"]
                  [pandect "0.5.2"]
-                 [com.stuartsierra/component "0.2.3"]]
+                 [com.stuartsierra/component "0.2.3"]
+                 [com.brunobonacci/safely "0.1.0-SNAPSHOT"]]
 
   :deploy-repositories [["clojars" {:url "https://clojars.org/repo/"
                                     :sign-releases false}]])

src/ip_geoloc/maxmind.clj

@@ -1,5 +1,6 @@
 (ns ip-geoloc.maxmind
-  (:require [clojure.java.io :as io])
+  (:require [clojure.java.io :as io]
+            [safely.core :refer [safely sleep]])
   (:require [pandect.algo.md5 :as hash])
   (:require [clj-http.client :as http])
   (:import com.maxmind.geoip2.DatabaseReader$Builder
@@ -118,7 +119,10 @@
     "get a concise geo IP lookup")
 
   (coordinates [this ip]
-    "get only coordinates info."))
+    "get only coordinates info.")
+
+  (database-location [this]
+    "Returns the path of the current database"))
 
 
 (defmacro if-ip-exists [& body]
@@ -133,14 +137,16 @@
   GeoIpProvider
 
   (init [this]
-    (let [db (if (.endsWith db-path ".gz")
+    (let [db-path (if (string? db-path) db-path (.getAbsolutePath db-path))
+          db (if (.endsWith db-path ".gz")
                (java.util.zip.GZIPInputStream.
                 (io/input-stream db-path))
                (io/input-stream db-path))]
       (MaxMind2. db-path (.build (DatabaseReader$Builder. db)))))
 
   (close [this]
-    (.close db)
+    (when db
+      (.close db))
     nil)
 
   (full-geo-lookup [this ip]
@@ -166,7 +172,10 @@
   (coordinates [this ip]
     (if-ip-exists
      (->clojure
-      (.getLocation (.city db (java.net.InetAddress/getByName ip)))))))
+      (.getLocation (.city db (java.net.InetAddress/getByName ip))))))
+
+  (database-location [this]
+    db-path))
 
 
 (defn- gunzip-file [in out]
@@ -187,8 +196,13 @@
    (io/file to)))
 
 
-(defn check-db [md5 file]
-  (= md5 (hash/md5-file file)))
+(defn check-db [md5 afile]
+  (when afile
+    (= md5
+       (safely
+        (hash/md5-file afile)
+        :on-error
+        :default nil))))
 
 
 (defn fetch-db-md5 [url]
@@ -197,21 +211,121 @@
 
 (defn update-db [{:keys [database-url database-md5-url database-folder]}]
   (let [dbgz (io/file database-folder "GeoLite2-City.mmdb.gz")
-        db   (io/file database-folder "GeoLite2-City.mmdb")]
+        db   (io/file database-folder
+                      (str "GeoLite2-City.mmdb." (System/currentTimeMillis)))]
     (download-db database-url dbgz)
     (gunzip-file dbgz db)
-    (check-db (fetch-db-md5 database-md5-url) db)))
+    (if (check-db (fetch-db-md5 database-md5-url) db)
+      (do
+        (let [newdb (io/file (str (.getAbsolutePath db) ".ok"))]
+          (.renameTo db newdb)
+          newdb))
+      (safely (.delete db) :on-error :ignore true))))
+
+
+(defn find-last-available-db [{:keys [database-folder]}]
+  (->> (io/file database-folder)
+       (.list)
+       (filter #(re-matches #"GeoLite2-City\.mmdb\.\d+\.ok" %))
+       (sort)
+       (last)))
+
+
+(defn update-db-if-needed [current-db-file
+                           {:keys [database-url database-md5-url
+                                   database-folder] :as cfg}]
+  (when-not (check-db (fetch-db-md5 database-md5-url) current-db-file)
+    (update-db cfg)))
+
+
+(comment
+  {:database-file nil
+   :database-folder "/tmp/maxmind"
+   :auto-update true
+   :auto-update-check-time (* 3 60 60 1000) ;; every 3 hours
+   :provider (atom nil)
+   :update-thread (atom nil)})
+
+
+(defn update-db! [{:keys [provider] :as config}]
+  (safely
+   (let [old-provider    @provider
+         current-db-file (when old-provider (database-location old-provider))
+         newdb (update-db-if-needed current-db-file config)]
+     (when newdb
+       (println "A new ip-geoloc db has been found:" newdb)
+       (let [new-provider (init (MaxMind2. newdb nil))]
+         (if (compare-and-set! provider old-provider new-provider)
+           (do
+             (when old-provider (close old-provider))
+             (println "new db successfully installed."))
+           (do
+             (when new-provider (close new-provider))
+             (println "WARN the new db couldn't be loaded."))))))
+
+   :on-error
+   :ignore true))
+
+
+(defn start-update-db-background-thread!
+  [{:keys [auto-update-check-time] :as config}]
+  (let [thread
+        (Thread.
+         (fn []
+           (loop []
+             (println "background thread to update ip-geoloc db started!")
+
+             (update-db! config)
+
+             (sleep auto-update-check-time :+/- 0.20)
+
+             ;; if the thread is interrupted then exit
+             (when-not (.isInterrupted (Thread/currentThread))
+               (recur))
+
+             (println "background thread to update ip-geoloc db stopped!")))
+         "ip-geoloc update thread")]
+    (.start thread)
+    (fn [] (.interrupt thread))))
 
 (comment
 
-  (download-db *database-url* "/tmp/GeoLite2-City.mmdb.gz")
-  (gunzip-file "/tmp/GeoLite2-City.mmdb.gz" "/tmp/GeoLite2-City.mmdb")
+  (def lastdb
+    (update-db {:database-url *database-url*
+                :database-md5-url *database-md5-url*
+                :database-folder  "/tmp/dir2"}))
+
+  (update-db-if-needed lastdb
+                       {:database-url *database-url*
+                        :database-md5-url *database-md5-url*
+                        :database-folder  "/tmp/dir2"})
+
+
+  (def cfg {:database-file nil
+            :database-folder "/tmp/maxmind"
+            :auto-update true
+            :auto-update-check-time (* 3 1000) ;; every 3 hours
+            :provider (atom nil)
+            :update-thread (atom nil)
+            :database-url *database-url*
+            :database-md5-url *database-md5-url*
+            })
+
+
+  (update-db! cfg)
+
+  (database-location @(:provider cfg))
+
+  (def t (start-update-db-background-thread! cfg))
+
+  (t)
+
+  (update-db-if-needed nil
+                       cfg)
 
-  (check-db
-   (fetch-db-md5 *database-md5-url*)
-   "/tmp/GeoLite2-City.mmdb")
 
-  (update-db {:database-url *database-url*
-              :database-md5-url *database-md5-url*
-              :database-folder  "/tmp/dir2"})
+  (def p (MaxMind2. "/tmp/maxmind/GeoLite2-City.mmdb.1442851935955.ok" nil))
+  (def p (init p))
+  (close p)
+  (database-location nil)
   )