Merge pull request #32 from redvox/issue-28-add-junction

Add junction to control flow.  Fixes #28.

src/clj/lambdacd/internal/execution.clj

@@ -92,7 +92,7 @@
 (defn- to-context-and-step [ctx step-results-channel]
   (fn [idx step]
     (let [parent-step-id (:step-id ctx)
-          new-step-id (cons (inc idx) parent-step-id)
+          new-step-id (step-id/child-id parent-step-id (inc idx))
           step-ctx (assoc ctx :step-id new-step-id
                               :step-results-channel step-results-channel)]
     [step-ctx step])))
@@ -221,4 +221,4 @@
   (let [next-build-number (pipeline-state/next-build-number (:pipeline-state-component context))]
     (async/thread
       (retrigger pipeline context build-number step-id-to-run next-build-number ))
-    next-build-number))
+    next-build-number))

src/clj/lambdacd/internal/step_id.clj

@@ -23,4 +23,7 @@
 (defn before? [a b]
   (and
     (not (= a b))
-    (not (later-than? a b))))
+    (not (later-than? a b))))
+
+(defn child-id [parent-step-id child-number]
+  (cons child-number parent-step-id))

src/clj/lambdacd/steps/control_flow.clj

@@ -3,6 +3,7 @@
   (:require [lambdacd.core :as core]
             [clojure.core.async :as async]
             [lambdacd.steps.support :as support]
+            [lambdacd.internal.step-id :as step-id]
             [lambdacd.steps.status :as status]))
 
 (defn- post-process-container-results [result]
@@ -59,4 +60,14 @@
   (fn [args ctx]
     (post-process-container-results
       (core/execute-steps steps args ctx
-                          :unify-status-fn status/successful-when-all-successful))))
+                          :unify-status-fn status/successful-when-all-successful))))
+
+(defn- child-context [ctx child-number]
+  (assoc ctx :step-id (step-id/child-id (:step-id ctx) child-number)))
+
+(defn ^{:display-type :parallel} junction [condition-step success-step failiure-step]
+  (fn [args ctx]
+    (post-process-container-results
+      (if (= :success (:status (core/execute-step args [(child-context ctx 1) condition-step])))
+        (core/execute-step args [(child-context ctx 2) success-step])
+        (core/execute-step args [(child-context ctx 3) failiure-step])))))

test/clj/lambdacd/steps/control_flow_test.clj

@@ -54,6 +54,12 @@
 (defn some-step-that-returns-42 [args ctx]
   {:status :success :the-number 42})
 
+(defn some-step-that-returns-foo [args ctx]
+  {:status :success :message :foo})
+
+(defn some-step-that-returns-bar [args ctx]
+  {:status :success :message :bar})
+
 (deftest in-parallel-test
   (testing "that it collects all the outputs together correctly"
     (is (map-containing {:outputs { [1 0 0] {:foo :baz :status :undefined} [2 0 0] {:foo :baz :status :undefined}} :status :undefined} ((in-parallel some-step some-step) {} (some-ctx-with :step-id [0 0])))))
@@ -110,3 +116,11 @@
       (is (= [[:status :running]
               [:status :waiting]
               [:status :success]] (slurp-chan result-ch))))))
+
+(deftest junction-test
+  (testing "that it executes the success-step if the condition is a success"
+    (is (map-containing {:outputs {[2 0 0] {:status :success :message :foo}}}
+                        ((junction some-successful-step some-step-that-returns-foo some-step-that-returns-bar) {} (some-ctx-with :step-id [0 0])))))
+  (testing "that it executes the success-step if the condition is a success"
+    (is (map-containing {:outputs {[3 0 0] {:status :success :message :bar}}}
+                        ((junction some-failing-step some-step-that-returns-foo some-step-that-returns-bar) {} (some-ctx-with :step-id [0 0]))))))