Handle backend errors

Author: dtaniwaki

lib/configproxy.js

@@ -384,19 +384,23 @@ class ConfigurableProxy extends EventEmitter {
   }
 
   targetForReq(req) {
-    var timer = this.statsd.createTimer("find_target_for_req");
-    // return proxy target for a given url path
-    var basePath = this.hostRouting ? "/" + parseHost(req) : "";
-    var path = basePath + decodeURIComponent(URL.parse(req.url).pathname);
-
-    return this._routes.getTarget(path).then(function (route) {
-      timer.stop();
-      if (route) {
-        return {
-          prefix: route.prefix,
-          target: route.data.target,
-        };
-      }
+    return new Promise((resolve, reject) => {
+      var timer = this.statsd.createTimer("find_target_for_req");
+      // return proxy target for a given url path
+      var basePath = this.hostRouting ? "/" + parseHost(req) : "";
+      var path = basePath + decodeURIComponent(URL.parse(req.url).pathname);
+
+      resolve(
+        this._routes.getTarget(path).then(function (route) {
+          timer.stop();
+          if (route) {
+            return {
+              prefix: route.prefix,
+              target: route.data.target,
+            };
+          }
+        })
+      ).catch((e) => reject(e));
     });
   }
 
@@ -598,6 +602,10 @@ class ConfigurableProxy extends EventEmitter {
           }
         });
       }
+    })
+    .catch(function (e) {
+      if (res.finished) throw e;
+      that.handleProxyError(500, kind, req, res, e);
     });
   }
 

test/proxy_spec.js

@@ -379,6 +379,20 @@ describe("Proxy Tests", function () {
       .then(done);
   });
 
+  it("backend error", function (done) {
+    var proxyPort = 55550;
+    util
+      .setupProxy(proxyPort, { errorTarget: "http://127.0.0.1:55565" }, [])
+      .then(() => r("http://127.0.0.1:" + proxyPort + "/%"))
+      .then((body) => done.fail("Expected 500"))
+      .catch((err) => {
+        expect(err.statusCode).toEqual(500);
+        expect(err.response.headers["content-type"]).toEqual("text/plain");
+        expect(err.response.body).toEqual("/%");
+      })
+      .then(done);
+  });
+
   it("Redirect location untouched without rewrite options", function (done) {
     var redirectTo = "http://foo.com:12345/whatever";
     util