Update again

Author: minwoox

armeria_client_detail.md renamed to armeria_internal.md

@@ -15,7 +15,7 @@
     - `Subscriber.onComplete()` or `Subscriber.onError(throwable)` is called depending on the situation.
 - Reactive Streams implementations in Armeria
   - `Publisher` (`StreamMessage`)
-    - `HttpRequest` and `HttpResponse` implement it
+    - `HttpRequest` and `HttpResponse` extends it
     - `DefaultStreamMessage`
       - Queue based
     - `AbstractStreamMessageDuplicator`
@@ -27,12 +27,13 @@
     - `FilteredStreamMessage`
       - What if we want to add some header in the decorator?
     - `DeferredStreamMessage`
-  - Let's implement my own subscriber.
+      - Deferred?
+  - Let's implement our own subscriber.
   - `Subscriber`
     - `HttpMessageAggregator`
-      - `HttpClient.execute(...)` returns an `HttpResponse` which is one of `StreamMessage`s
+      - `HttpClient.execute(...)` returns an `HttpResponse`.
       - You can aggregate the `HttpResponse` using `HttpResponse.aggregate()`.
-      - Then, it will return a `CompletableFuture<AggregatedHttpMessage>`.
+      - Then, it will return a `CompletableFuture<AggregatedHttpResponse>`.
       - In `HttpResponse.aggregate()`, `HttpMessageAggregator` which is a `Subscriber`, subscribes
       the `StreamMessage` and it collects all the response.
     - `HttpRequestSubscriber`
@@ -45,21 +46,28 @@
         it consumes all the elements.
       - `Http1ResponseDecoder` implements `ChannelInboundHandler`.
     - `HttpResponseSubscriber` is used by the server side.
-
+    - Let's build a simple decorating service.
+  - The difference between `HttpRequest` and `HttpResponse`
+  
 ### Event Loop
 
 - Who does the all jobs above?
-- What is Event loop?
+- What is the event loop?
   - A general term which waits for and dispatches events or messages in a program.
   - We use `EventLoop` in Netty.
     - Handles all the I/O operations for a `Channel` once registered.
     - One `EventLoop` instance usually handles more than one `Channel` but this may depend on implementation details and internals.
     - `EventLoop` extends Java's `ScheduledExecutorService`.
     - Events and Tasks are executed in order received.
     - Let's see what it really does with [`EpollEventLoop`](https://github.com/netty/netty/blob/05e5ab1ecb98963604d686c1f59b2196cf73e244/transport-native-epoll/src/main/java/io/netty/channel/epoll/EpollEventLoop.java#L257)
+  - From the point of view of the `EventLoop`s   
 - How many `EventLoop`s ?
   - No official formula
     - Nthreads = Ncpu * Ucpu * (1 + W/C)
+- Let's build a simple reactive server.
+    
+### Request flow
+
 - Sending an `HttpRequest`
   - `HttpClient` -> `UserClient` -> HTTP decorators -> `HttpClientDelegate` -> `HttpSessionHandler`
   - Creates a `ClientRequestContext` in `UserClient`
@@ -71,13 +79,27 @@
     - So the thread who calls `HttpClient.execute()` and write to the `Channel` can be different.
 - Receiving an `HttpResponse`
   - The thread who writes to the response is the `EventLoop` you used when sending the `Request`.
+- Thrift client
+  - `HelloSerivce.Iface()` or `AsyncIface()` -> `THttpClientInvocationHandler` -> `DefaultTHttpClient(UserClient)` ->
+  RPC decorators -> `THttpClientDelegate` -> HTTP decorators -> `HttpClientDelegate`
+  
+### `RequestContext`
+
+- Thread-local storage
+  - `makeContextAware`
 
 ### Connection pooling
 
+- How many connections we have?
+  - HTTP/1.1
+    - What's the [pipelining](https://en.wikipedia.org/wiki/HTTP_pipelining)?
+    - [In Armeria](https://github.com/line/armeria/blob/armeria-0.88.0/core/src/main/java/com/linecorp/armeria/client/HttpClientDelegate.java#L224)
+  - HTTP/2
+    - Why is it possible just to have one connection?
+      - What Content-length header is for?
+    - [Frame format](https://tools.ietf.org/html/rfc7540#section-4.1)
+  
 - Creates a [`PoolKey`](https://github.com/line/armeria/blob/d90aea4704982df06251c1132bbc4da33301725d/core/src/main/java/com/linecorp/armeria/client/HttpClientDelegate.java#L104) with host, ip, port and session protocol.
 - Gets a [`KeyedChannelPool`](https://github.com/line/armeria/blob/d90aea4704982df06251c1132bbc4da33301725d/core/src/main/java/com/linecorp/armeria/client/HttpClientFactory.java#L289) using the `EventLoop`.
-- Gets a healthy `Channel` from the pool using the key.
-
-### Thrift client
 
-- `HelloSerivce.Iface()` or `AsyncIface()` -> `THttpClientInvocationHandler` -> `DefaultTHttpClient(UserClient)` -> RPC decorators -> `THttpClientDelegate` -> HTTP decorators -> `HttpClientDelegate`
+### Let's build a proxy server

build.gradle

@@ -0,0 +1,32 @@
+plugins {
+    id "io.spring.dependency-management" version "1.0.8.RELEASE"
+}
+
+apply plugin: 'java'
+apply plugin: 'idea'
+
+repositories {
+    mavenCentral()
+}
+
+dependencyManagement {
+    imports {
+        mavenBom 'com.linecorp.armeria:armeria-bom:0.88.0'
+    }
+}
+
+dependencies {
+    compile 'com.linecorp.armeria:armeria'
+
+    testCompile 'com.linecorp.armeria:armeria-testing-junit'
+    testCompile 'org.assertj:assertj-core:3.12.2'
+    testCompile 'org.awaitility:awaitility:4.0.0-rc1'
+}
+
+tasks.withType(JavaCompile) {
+    sourceCompatibility = '1.8'
+    targetCompatibility = '1.8'
+    options.encoding = 'UTF-8'
+    options.debug = true
+    options.compilerArgs += '-parameters'
+}

samples/gradle/wrapper/gradle-wrapper.jar renamed to gradle/wrapper/gradle-wrapper.jar

@@ -1,6 +1,6 @@
-#Fri Jul 27 11:26:30 KST 2018
+#Thu Jul 25 12:34:08 KST 2019
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.5-all.zip
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-all.zip
+zipStoreBase=GRADLE_USER_HOME

samples/gradle/wrapper/gradle-wrapper.properties renamed to gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1 @@
+rootProject.name = 'misc'

samples/gradlew renamed to gradlew

@@ -0,0 +1,19 @@
+import com.linecorp.armeria.client.HttpClient;
+import com.linecorp.armeria.common.AggregatedHttpResponse;
+import com.linecorp.armeria.common.HttpResponse;
+
+public class DecoratingService {
+
+    public static void main(String[] args) {
+        // build server
+
+        sendRequest();
+    }
+
+    private static void sendRequest() {
+        final HttpClient client = HttpClient.of("http://127.0.0.1:8080");
+        final HttpResponse httpResponse = client.get("/test");
+        final AggregatedHttpResponse res = httpResponse.aggregate().join();
+        System.err.println(res.headers());
+    }
+}