Feature/297 customize request routing outside knots #299

mariuszkubis · 2017-04-28T08:16:37Z

I hereby agree to the terms of the Knot.x Contributor License Agreement.

Previously, every request in Knot.X was routed through:
-Server
-RepositoryConnector
-FragmentSplitter
-customizable Knots (Engine)
-FragmentAssembler

This is now called a "default flow", a typical way of processing requests in Knot.X

Here, we introduce a new way of processing - "custom flow", which allows you to omit some blocks of the default flow.

A custom flow consists of:
-Server
-Gateway knot which sets the knot context of the request
-customizable Knots (Engine)
-Response provider Knot, which returns the result to the client (like FragmentAssembler in default flow, but it doesn't operate on Fragments)

To test this solution, run Example App and visit http://localhost:8092/customFlow/remote/simple.json to retrieve a JSON message processed by a custom flow.

…flows

toniedzwiedz · 2017-05-14T13:13:01Z

documentation/src/main/wiki/GatewayMode.md

@@ -0,0 +1,41 @@
+# Gateway Mode
+
+The gateway mode provides an alternative way of processing requests, alternative to than presented in [[Knot Routing section|KnotRouting]].


The gateway mode provides an alternative way of processing requests, alternative to than presented in [[Knot Routing section|KnotRouting]].

Some repetition and awkward grammar here. How about rewriting this as follows:

The gateway mode provides a way of processing requests alternative to that presented in the [[Knot Routing section|KnotRouting]].

toniedzwiedz · 2017-05-14T13:14:09Z

documentation/src/main/wiki/GatewayMode.md

+
+After the routing is over, the response is returned from a verticle called Response Provider. 
+
+//TODO an image of the routing simillar to this on Knot Routing page


Will this be provided as part of this Pull Request?

It should be done as part of this PR.

Unfortunately, I do not have access to the images in editable form.
If you can provide it, I will create the needed image.

toniedzwiedz · 2017-05-14T13:14:36Z

documentation/src/main/wiki/GatewayMode.md

+
+//TODO an image of the routing simillar to this on Knot Routing page
+
+Depending of your routing implementation, you can use the Gateway Mode to return the external services response 


Depending on

toniedzwiedz · 2017-05-14T13:16:09Z

documentation/src/main/wiki/HighLevelArchitecture.md

@@ -13,7 +13,7 @@ Diagram below depicts high level Knot.x architecture.

 Custom business logic can be encapsulated in dedicated Knots / Adapters.

-Knot is module which defines custom step while [request routing](#KnotRouting). It can process custom
+Knot is module which defines custom step while [[request routing|KnotRouting]]. It can process custom


Awkward grammar.

A Knot is a module which defines a custom step in the process of [[request routing|KnotRouting]].

toniedzwiedz · 2017-05-14T13:17:15Z

documentation/src/main/wiki/KnotRouting.md

@@ -86,3 +86,6 @@ Knot performs its business logic and returns a transition. The transition define
 In some cases Knot can decide to break the route and redirect the user to a different page.

 When all Knots on the route processed the request or one of Knots break the routing, Server returns a response to the user.
+
+It is also possible to define custom request flow, skipping Repository Connector, Fragment Splitter and Fragment Assembler. 


a custom request flow

toniedzwiedz · 2017-05-14T13:19:17Z

documentation/src/main/wiki/Server.md

@@ -116,6 +121,7 @@ In short, by default, server does:
 - Listens on port 8092
 - Displays exception details on error pages (for development purposes)
 - Returns certain headers in Http Response to the client (as shown above)
+- Uses [[default Knot.X routing mechanism|KnotRouting]]


Uses the default Knot.x routing mechanism.

malaskowski

Really great work, thank you guys.
I left some comments.

malaskowski · 2017-05-24T13:33:12Z

knotx-gateway/src/main/java/io/knotx/gateway/impl/RequestProcessorKnotProxyImpl.java

+
+public class RequestProcessorKnotProxyImpl extends AbstractKnotProxy {
+
+  private final static String RESPONSE = "{\"message\":\"This is a sample custom flow response\"}";


Should this class be a part of gateway implementation? It rather looks like an example. Maybe in such case this should go to knotx-examples or even to wiki docs?

Absolutely, this class was here just to show some example use-case and should not be a part of the implementation.
I've moved the RequestProcessorKnot to knotx-example module and updated the docs. I think having an example usage of Gateway Mode in the example application is beneficial.

malaskowski · 2017-05-24T13:35:31Z

knotx-server/src/main/java/io/knotx/server/KnotxGatewayResponseProviderHandler.java

+                }
+              },
+              error -> {
+                LOGGER.error("Error happened while communicating with {} engine", error,


Missing one {} in this log message.

malaskowski · 2017-05-24T13:38:19Z

knotx-server/src/main/java/io/knotx/server/SupportedMethodsAndPathsHandler.java

+    HttpMethod method = context.request().method();
+    boolean pathNotAllowedInDefaultFlow = isPathNotPresentInFlow(path, defaultFlow);
+    boolean pathNotAllowedInCustomFlow = isPathNotPresentInFlow(path, customFlow);
+    if (pathNotAllowedInDefaultFlow && pathNotAllowedInCustomFlow) {


This is a candidate for some unit tests.

…pdate Gateway Mode documentation

malaskowski · 2017-05-25T09:27:37Z

knotx-server/src/main/java/io/knotx/server/SupportedMethodsAndPathsHandler.java

      context.fail(HttpResponseStatus.NOT_FOUND.code());
+    } else if (!pathNotAllowedInDefaultFlow && isMethodDisallowedInFlow(method, defaultFlow)) {


So.. what exactly should happen, when defaultPath and defaultMethod are not allowed, but customPath and customMethod are allowed :) ?
It looks that we finish without any action on context (tip: there is double if).

malaskowski · 2017-05-25T15:11:58Z

I've refactored a bit and (I think that I...) fixed SupportedMethodsAndPathsHandler case I mentioned above.
Please check if this is still valid :)
I also added a unit test for this handler.

Please correct me if I'm wrong - this custom flow feature enables defining only a single custom routing? It is not possible to create two or more custom flows?

rkarwacki · 2017-05-25T17:39:39Z

@Skejven - that looks great.

Yes, it is possible to define only one custom flow. Why? Because you can still process your request in any way you want by plugging your custom logic between GatewayKnot and ResponseProviderKnot. They provide a minimal functionality to process any request - setting up the RequestContext and returning the response. We couldn't figure out a case when someone might need a few custom flows.

Similarly, you can only have one KnotRouting in the default flow - once the fragments are split, you can process them in any way you want, and the universal way of returning them is to route them through the FragmentAssembler. Having a second KnotRouting would not be beneficial because in every case, they could have been merged into one. The same applies to the Gateway Mode feature.

I think that the feature is quite powerful, and possibly you could even get rid of the default flow if you really wanted to, since you could just plug the whole existing logic (Connectors, Splitter, KnotRouting, Assembler) between GatewayKnot and ResponseProviderKnot on some paths. In this case, you could still have the ability to define any other custom routings.

malaskowski · 2017-05-26T07:32:47Z

Thanks @rkarwacki for explaining. I've added smal code refactors and I think work is ready to merge. This is great feature, thank you guys!

mariuszkubis and others added 16 commits April 25, 2017 15:29

Customize request routing outside Knots

45c21f8

Implement custom request processing flow

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Customize request routing outside Knots

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Customize request routing outside Knots: tests fix

e2f14d5

Customize request routing outside Knots: tests fix

f10d16a

Customize request routing outside Knots: clean up

66f919a

Customize request routing outside Knots: clean up

1b03194

Customize request routing outside Knots: clean up

2c10cef

Customize request routing outside Knots: removed unused loggers

53b1b74

Customize request routing outside Knots: removed unused loggers

d355c28

Customize request routing outside Knots: removed unused loggers

48e222b

Customize request routing outside Knots: removed unused loggers

1e7a8f0

Customize request routing outside Knots: removed unused loggers

993c017

Refactor retrieving verticle addresses from configuration

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Refactor retrieving verticle addresses from configuration

86719d5

Cleanup generated logback file

3d3eb91

rkarwacki requested review from marcinczeczko, tomaszmichalak and malaskowski May 2, 2017 18:09

Update documentation - add information about gateway mode and custom …

dfc0521

…flows

toniedzwiedz reviewed May 14, 2017

View reviewed changes

malaskowski added 2 commits May 24, 2017 15:10

merge with master and resolve conflicts

b8d0b20

Fixed grammar CR

0a2438b

malaskowski requested changes May 24, 2017

View reviewed changes

Move request processor knot to example application as a new module. U…

b6ac5b4

…pdate Gateway Mode documentation

malaskowski reviewed May 25, 2017

View reviewed changes

fixed SupportedMethodsHandler and unit tests

5c38d77

docs fixes

f997a5c

small CR fixes and simplifications

0cf1639

malaskowski approved these changes May 26, 2017

View reviewed changes

malaskowski merged commit 42a0341 into master May 26, 2017

malaskowski deleted the feature/297-customize-request-routing-outside-knots branch May 26, 2017 14:15

tomaszmichalak mentioned this pull request Jun 4, 2017

Customize request routing outside Knots #297

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Feature/297 customize request routing outside knots #299

Feature/297 customize request routing outside knots #299

mariuszkubis commented Apr 28, 2017

toniedzwiedz May 14, 2017

toniedzwiedz May 14, 2017

malaskowski May 24, 2017

rkarwacki May 24, 2017

toniedzwiedz May 14, 2017

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toniedzwiedz May 14, 2017

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malaskowski commented May 25, 2017 •

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malaskowski commented May 26, 2017

		@@ -0,0 +1,41 @@
		# Gateway Mode

		The gateway mode provides an alternative way of processing requests, alternative to than presented in [[Knot Routing section\|KnotRouting]].


		After the routing is over, the response is returned from a verticle called Response Provider.

		//TODO an image of the routing simillar to this on Knot Routing page


		//TODO an image of the routing simillar to this on Knot Routing page

		Depending of your routing implementation, you can use the Gateway Mode to return the external services response


		public class RequestProcessorKnotProxyImpl extends AbstractKnotProxy {

		private final static String RESPONSE = "{\"message\":\"This is a sample custom flow response\"}";

		context.fail(HttpResponseStatus.NOT_FOUND.code());
		} else if (!pathNotAllowedInDefaultFlow && isMethodDisallowedInFlow(method, defaultFlow)) {

Feature/297 customize request routing outside knots #299

Feature/297 customize request routing outside knots #299

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mariuszkubis commented Apr 28, 2017

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