-
Notifications
You must be signed in to change notification settings - Fork 53
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
Showing
107 changed files
with
3,070 additions
and
1,636 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,95 @@ | ||
| # Message cookie | ||
|
|
||
| ## Concept | ||
| The goal of this approach is to be able to route response into specific handler (the handler that have produced request) | ||
| into specific service into specific application/storm-bolt. | ||
|
|
||
| The message producer must include into the message info unambiguously describing the sender (into hierarchical manner) - | ||
| the message cookie object. Message recipient must produce response and copy message cookie from request. So the only | ||
| task for message recipient in this approach is to copy message cookie from request into response. | ||
|
|
||
| Message cookie hierarchy represent/mirror code hierarchy that produce this cookie - for example, from innermost to | ||
| outermost layers: `unique-request-id => unique-handler-id => service-id`. During message producing each code layer must | ||
| add corresponding cookie layer. | ||
|
|
||
| Message cookie must be placed into message envelope (`BaseMessage` and inheritors in our terminology). It will simplify | ||
| its copying on recipient side - message cookie will not be passed into code that handle request itself but copied on the | ||
| level responsible for message decoding/encoding. At same time on request producer side, carrier decorators can add | ||
| extra message cookie layers during delivering message payload into message ejecting level without any interaction with | ||
| message payload object. | ||
|
|
||
| Keeping all dispatch info into request/response objects relief from keeping it somewhere on request side and as result | ||
| no need to track it for invalidation and obsolescence. | ||
|
|
||
|  | ||
|
|
||
| ## Wrapping process | ||
|
|
||
| Cookie wrapping or layer adding process can be done by carrier(objects responsible for communication with transport layer) | ||
| decorators. I.e. application produce service and provide carrier object decorated with object that will add service | ||
| name cookie layer to each produced requests. | ||
|
|
||
| For example, we have an interface defining some carrier that will be used by service and by handlers inside service: | ||
|
|
||
| ```java | ||
| public interface SomeCarrier { | ||
| void sendCommandToSpeaker(CommandData command, @NonNull MessageCookie cookie); | ||
| } | ||
| ``` | ||
|
|
||
| We can define a decorator that adds some cookie layer during request to the `sendSpeakerCommand`. | ||
|
|
||
| ```java | ||
| public class SomeCarrierDecorator implements SomeCarrier { | ||
| private final SomeCarrier target; | ||
| private final String layerValue; | ||
|
|
||
| public SomeCarrierDecorator(SomeCarrier target, String layerValue) { | ||
| this.target = target; | ||
| this.layerValue = layerValue; | ||
| } | ||
|
|
||
| public void sendCommandToSpeaker(CommandData command, @NonNull MessageCookie cookie) { | ||
| target.sendCommandToSpeaker(command, new MessageCookie(layerValue, cookie)); | ||
| } | ||
| } | ||
| ``` | ||
|
|
||
| And on application init we will create service in this way: | ||
|
|
||
| ```java | ||
| public class App { | ||
| Map<Sting, ServiceBase> services = new Map<>(); | ||
|
|
||
| public void init() { | ||
| SomeService someService = new SomeService(new SomeCarrierDecorator(carrier, "some_service_name")); | ||
| serivces.put("some_service_name", someService); | ||
| } | ||
| } | ||
| ``` | ||
|
|
||
| So on response we can locate required service in this way: | ||
|
|
||
| ```java | ||
| public class App { | ||
| Map<Sting, ServiceBase> services = new Map<>(); | ||
|
|
||
| public void dispatch(MessageData payload, MessageCookie cookie) { | ||
| ServiceBase service = services.get(cookie.getValue()); | ||
| if (service != null) { | ||
| service.dispatch(payload, cookie.getNested()); | ||
| } else { | ||
| log.error("dispatch error"); | ||
| } | ||
| } | ||
| } | ||
| ``` | ||
|
|
||
| Service itself can add one more decorator to the carrier, responsible for adding handler unique id cookie layer. And | ||
| dispatching can be continued inside service. So each code layer process it's own message cookie layer and fully control | ||
| the meaning of cookie value (on specific layer). | ||
|
|
||
| ## Some possible tooling improvements | ||
|
|
||
| `MessageCookie` can define equals/hash methods that do not take into account value of nested field/cookie. In this case | ||
| cookie object itself can be used as `Map` key during dispatch. |
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,52 @@ | ||
| @startuml | ||
| title message round trip | ||
|
|
||
| collections handler | ||
| collections service | ||
| participant application | ||
| participant transport | ||
| participant remote | ||
| collections remote_handler | ||
|
|
||
| activate handler | ||
| handler -> handler : produce message payload\nand message cookie\nwith unique request id\n[payload, cookie[0]] | ||
| handler -> service : [payload, cookie[0]] | ||
| deactivate handler | ||
| service -> application : add handler-id layer\n[payload, cookie[1]] | ||
| application -> transport : add service name layer\n[payload, cookie[2]] | ||
|
|
||
| activate transport | ||
| transport -> transport : [payload, cookie[2]] => [request_message] | ||
| transport -> remote: [request_message] | ||
| deactivate transport | ||
|
|
||
| activate remote | ||
| remote -> remote : [request_message] => [payload, cookie[2]] | ||
| remote -> remote_handler : [payload] | ||
| activate remote_handler | ||
| remote_handler -> remote : [response] | ||
| deactivate remote_handler | ||
| remote -> remote : response + cookie[2] => [response_message] | ||
| remote -> transport : [response_message] | ||
| deactivate remote | ||
|
|
||
| activate transport | ||
| transport -> transport : [response_message] => [response, cookie[2]] | ||
| transport -> application : [response, cookie[2]] | ||
| deactivate transport | ||
|
|
||
| activate application | ||
| application -> application : select service by cookie[2]\nunwrap | ||
| application -> service : [response, cookie[1]] | ||
| deactivate application | ||
|
|
||
| activate service | ||
| service -> service : select handler by cookie[1]\nunwrap | ||
| service -> handler : [response, cookie[0]] | ||
| deactivate service | ||
|
|
||
| activate handler | ||
| handler -> handler : identify request by cookie[0]\nhandle response | ||
| deactivate handler | ||
|
|
||
| @enduml |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.