Merge branch 'log-testing'

Author: ataggart

CHANGELOG.md

@@ -6,6 +6,14 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ([despite its flaws](https://www.youtube.com/watch?v=oyLBGkS5ICk)).
 
 ## [Unreleased]
+### Added
+- Add support for testing logs in `clojure.tools.logging.test`
+
+### Changed
+- Now passes the context classloader of current thread to `Class/forName` when
+  determining whether logging implementation classes are available on the
+  classpath. This was done to allow testing of the various `impl/*-factory`
+  functions, and seems consistent with clojure internals.
 
 ## [0.4.1] - 2018-05-07
 ### Fixed

README.md

@@ -27,7 +27,7 @@ The following short example should give you what you need to get started:
 (defn divide [x y]
   (log/info "dividing" x "by" y)
   (try
-    (log/spyf "result: %s" (/ x y)) ; yields the result
+    (log/spyf "result is %s" (/ x y)) ; yields the result
     (catch Exception ex
       (log/error ex "There was an error in calculation"))))
 ```

project.clj

@@ -6,9 +6,13 @@
   :source-paths ["src/main/clojure"]
   :test-paths ["src/test/clojure"]
   :dependencies [[org.clojure/clojure "1.3.0"]]
-  :profiles {:test {:dependencies [[org.slf4j/slf4j-api "1.6.2"]
-                                   [org.slf4j/slf4j-log4j12 "1.6.2"]
-                                   [log4j "1.2.16"]
-                                   [org.apache.logging.log4j/log4j-api "2.8.2"]
-                                   [org.apache.logging.log4j/log4j-core "2.8.2"]
-                                   [commons-logging "1.1.1"]]}})
+  :aliases {"cloverage" ["with-profile" "dev,cloverage" "cloverage" "--fail-threshold" "100"]}
+  :profiles {:cloverage {:plugins [[lein-cloverage "1.0.9"]]}
+             :dev       {:dependencies [[org.clojure/clojure "1.8.0"]
+                                        [org.clojure/test.check "0.9.0"]
+                                        [org.slf4j/slf4j-api "1.6.2"]
+                                        [org.slf4j/slf4j-log4j12 "1.6.2"]
+                                        [log4j "1.2.16"]
+                                        [org.apache.logging.log4j/log4j-api "2.8.2"]
+                                        [org.apache.logging.log4j/log4j-core "2.8.2"]
+                                        [commons-logging "1.1.1"]]}})

src/main/clojure/clojure/tools/logging/impl.clj

@@ -44,12 +44,22 @@
     (name [_] "disabled")
     (get-logger [_ _] disabled-logger)))
 
+(defn class-found?
+  "Returns true if the Class associated with the given classname can be found
+   using the context ClassLoader for the current thread."
+  [name]
+  (try
+    (Class/forName name true (.. Thread currentThread getContextClassLoader))
+    true
+    (catch ClassNotFoundException _
+      false)))
+
+
 (defn slf4j-factory
   "Returns a SLF4J-based implementation of the LoggerFactory protocol, or nil if
   not available."
   []
-  (try
-    (Class/forName "org.slf4j.Logger")
+  (when (class-found? "org.slf4j.Logger")
     (eval
       `(do
         (extend org.slf4j.Logger
@@ -88,15 +98,13 @@
           (name [_#]
             "org.slf4j")
           (get-logger [_# logger-ns#]
-            (org.slf4j.LoggerFactory/getLogger ^String (str logger-ns#))))))
-    (catch Exception e nil)))
+            (org.slf4j.LoggerFactory/getLogger ^String (str logger-ns#))))))))
 
 (defn cl-factory
   "Returns a Commons Logging-based implementation of the LoggerFactory protocol, or
   nil if not available."
   []
-  (try
-    (Class/forName "org.apache.commons.logging.Log")
+  (when (class-found? "org.apache.commons.logging.Log")
     (eval
       `(do
          (extend org.apache.commons.logging.Log
@@ -134,15 +142,13 @@
            (name [_#]
              "org.apache.commons.logging")
            (get-logger [_# logger-ns#]
-             (org.apache.commons.logging.LogFactory/getLog (str logger-ns#))))))
-    (catch Exception e nil)))
+             (org.apache.commons.logging.LogFactory/getLog (str logger-ns#))))))))
 
 (defn log4j-factory
   "Returns a Log4j-based implementation of the LoggerFactory protocol, or nil if
   not available."
   []
-  (try
-    (Class/forName "org.apache.log4j.Logger")
+  (when (class-found? "org.apache.log4j.Logger")
     (eval
       `(let [levels# {:trace org.apache.log4j.Level/TRACE
                       :debug org.apache.log4j.Level/DEBUG
@@ -165,15 +171,13 @@
            (name [_#]
              "org.apache.log4j")
            (get-logger [_# logger-ns#]
-             (org.apache.log4j.Logger/getLogger ^String (str logger-ns#))))))
-    (catch Exception e nil)))
+             (org.apache.log4j.Logger/getLogger ^String (str logger-ns#))))))))
 
 (defn log4j2-factory
   "Returns a Log4j2-based implementation of the LoggerFactory protocol, or nil if
   not available."
   []
-  (try
-    (Class/forName "org.apache.logging.log4j.Logger")
+  (when (class-found? "org.apache.logging.log4j.Logger")
     (eval
       `(let [levels# {:trace org.apache.logging.log4j.Level/TRACE
                       :debug org.apache.logging.log4j.Level/DEBUG
@@ -202,15 +206,13 @@
            (name [_#]
              "org.apache.logging.log4j")
            (get-logger [_# logger-ns#]
-             (org.apache.logging.log4j.LogManager/getLogger ^String (str logger-ns#))))))
-    (catch Exception e nil)))
+             (org.apache.logging.log4j.LogManager/getLogger ^String (str logger-ns#))))))))
 
 (defn jul-factory
   "Returns a java.util.logging-based implementation of the LoggerFactory protocol,
   or nil if not available."
   []
-  (try
-    (Class/forName "java.util.logging.Logger")
+  (when (class-found? "java.util.logging.Logger")
     (eval
       `(let [levels# {:trace java.util.logging.Level/FINEST
                       :debug java.util.logging.Level/FINE
@@ -234,8 +236,7 @@
            (name [_#]
              "java.util.logging")
            (get-logger [_# logger-ns#]
-             (java.util.logging.Logger/getLogger (str logger-ns#))))))
-    (catch Exception e nil)))
+             (java.util.logging.Logger/getLogger (str logger-ns#))))))))
 
 (defn find-factory
   "Returns the first non-nil value from slf4j-factory, cl-factory,