Append a caught exception to the dynamic output of a step instead of …

…discarding the dynamic output (fixes #174)

CHANGELOG.md

@@ -4,6 +4,12 @@ This changelog contains a loose collection of changes in every release. I will a
 
 The format is based on [Keep a Changelog](http://keepachangelog.com/) and this project adheres to a "shifted" version of semantic versioning while the major version remains at 0: Minor version changes indicate breaking changes, patch version changes should not contain breaking changes.
 
+## 0.13.5
+
+### Fixed
+
+* Output of steps that throw an exception gets lost (#174)
+
 ## 0.13.4
 
 ### Fixed

src/clj/lambdacd/execution/internal/execute_step.clj

@@ -28,7 +28,9 @@
     (try
       (handler args ctx)
       (catch Exception e
-        {:status :failure :out (util-exceptions/stacktrace-to-string e)}))))
+        {:status :failure
+         :out (util-exceptions/stacktrace-to-string e)
+         ::append-out-to-async-out true}))))
 
 ; ============================================
 
@@ -98,7 +100,11 @@
           immediate-step-result     (handler args ctx-for-child)
           processed-async-result    (async/<!! processed-async-result-ch)
           complete-step-result      (merge processed-async-result immediate-step-result)]
-      complete-step-result)))
+      (if (::append-out-to-async-out immediate-step-result)
+        (-> complete-step-result
+            (assoc :out (str (:out processed-async-result) (:out immediate-step-result)))
+            (dissoc ::append-out-to-async-out))
+        complete-step-result))))
 
 ; ============================================
 

test/clj/lambdacd/execution/internal/execute_step_test.clj

@@ -33,9 +33,16 @@
 
 (def message-thrown-by-some-step-throwing-an-exception
   "Something went wrong!")
+(def output-written-before-throwing-an-exception
+  "some output before throwing exception")
 
 (defn some-step-throwing-an-exception [& _]
   (throw (Exception. ^String message-thrown-by-some-step-throwing-an-exception)))
+
+(defn some-step-writing-output-then-throwing-an-exception [_ {c :result-channel}]
+  (async/>!! c [:out output-written-before-throwing-an-exception])
+  (throw (Exception. ^String message-thrown-by-some-step-throwing-an-exception)))
+
 (defn some-step-throwing-an-error [& _]
   (throw (Error. ^String message-thrown-by-some-step-throwing-an-exception)))
 
@@ -163,9 +170,10 @@
          (testing "that the result indicates that a step has been waiting"
                   (is (= {:outputs { [0 0] {:status :success :has-been-waiting true}} :status :success} (execute-step {} [(some-ctx-with :step-id [0 0]) some-step-sending-a-wait] ))))
          (testing "that if an exception is thrown in the step, it will result in a failure and the exception output is logged"
-                  (let [output (execute-step {} [(some-ctx-with :step-id [0 0]) some-step-throwing-an-exception])]
+                  (let [output (execute-step {} [(some-ctx-with :step-id [0 0]) some-step-writing-output-then-throwing-an-exception])]
                     (is (= :failure (get-in output [:outputs [0 0] :status])))
-                    (is (.contains (get-in output [:outputs [0 0] :out]) "Something went wrong"))))
+                    (is (.contains (get-in output [:outputs [0 0] :out]) message-thrown-by-some-step-throwing-an-exception))
+                    (is (.contains (get-in output [:outputs [0 0] :out]) output-written-before-throwing-an-exception))))
          (testing "that the context passed to the step contains an output-channel and that results passed into this channel are merged into the result"
                   (is (= {:outputs { [0 0] {:out "hello world" :status :success}} :status :success} (execute-step {} [(some-ctx-with :step-id [0 0]) some-step-writing-to-the-result-channel]))))
          (testing "that the context data is being passed on to the step"