prepared 1.0

Dockerfile

@@ -0,0 +1,9 @@
+FROM openjdk:11-jre
+
+WORKDIR /app
+
+ADD target/${project.build.finalName}-jar-with-dependencies.jar app.jar
+# ADD target/yaproxy-1.0-SNAPSHOT-jar-with-dependencies.jar app.jar
+# ADD config.yml .
+
+ENTRYPOINT ["java", "-jar", "app.jar", "config.yml"]

README.md

@@ -0,0 +1,91 @@
+# yaproxy - Yet Another Proxy
+
+## What it be
+
+yaproxy is an experimental proxy implementation for HTTP/1.1 written in Java.
+yaproxy is designed to be used alternatively as __reverse proxy__ or as traditional __forward proxy__.
+
+Used as __reverse proxy__ yaproxy sits between multiple clients and one or several instances of a downstream service. It supports multiple downstream services with multiple instances, downstream services are identified using the `Host` HTTP header.
+yaproxy listens to HTTP requests and forwards them to one of the instances of a downstream service that will process the requests.
+Requests are load-balanced and multiple load-balancing strategies are supported.
+After processing the request, the downstream service sends the HTTP response back to yaproxy, that forwards the response to the client making the initial request.
+
+Used as __forward proxy__ yaproxy works exactly the same: the difference is only its configuration.
+
+## Requirements
+* Java 11
+* Maven 3.3 (only for build)
+
+## Usage
+yaproxy reads its configuration from a file at start.
+A standard `config.yml` looks like:
+```
+proxy:
+  listen: 
+    address: "127.0.0.1"
+    port: 8080
+  services:
+    - name: my-service
+      domain: my-service.my-company.com
+      hosts:
+        - address: "127.0.0.1"
+          port: 8888
+        - address: "127.0.0.2"
+          port: 8888
+          #downstreamPoxy: localhost:8888
+```
+A full fledged configuration may provide additional parameters like `downstreamPoxy` and `loadBalancerStrategy`:
+```
+proxy:
+  listen: 
+    address: "127.0.0.1"
+    port: 8080
+  services:
+    - name: my-service
+      domain: my-service.my-company.com
+      #downstreamPoxy: localhost:8888
+      hosts:
+        - address: "127.0.0.1"
+          port: 8888
+        - address: "127.0.0.2"
+          port: 8888
+          #downstreamPoxy: localhost:8888
+  #downstreamPoxy: localhost:8888
+loadBalancerStrategy: ROUND_ROBIN | RANDOM
+```
+yaproxy can be executed using the command:
+`java -jar yaproxy-1.0-SNAPSHOT-jar-with-dependencies.jar config.yml`
+
+## Features
+* multiple load balancer strategies
+  * `RANDOM` (default)
+  * `ROUND_ROBIN`
+* in-memory cache, compliant with HTTP/1.1 header `Cache-Control`
+  * matching regex [*(public, *)?(max-age|s-maxage)=(\d+)](https://regex101.com/r/1Gpcn6/1)
+  * automatic cache invalidation (every 1') whenever cache entries expired
+* support for downstream proxy (though without authentication mechanism)
+
+## Known limitations
+* No support for HTTPS
+* No support for chunked response entities nor for compressed response content
+* Headers from cached responses are forwarded as they were originally received (neither filtered nor adjusted)
+
+## Third-party libraries
+* org.yaml
+* junit
+* org.apache.logging.log4j
+* org.apache.httpcomponents
+
+## References
+* [RFC 2616 about HTTP/1.1](https://tools.ietf.org/html/rfc2616)
+* [Java Concurrency with Load Balancer Simulation](https://turkogluc.com/java-concurrency-with-load-balancer-simulation/)
+
+## Contributing
+
+Contributions are welcome.
+
+## Copyright / License
+
+Copyright 2021 Yaproxy
+
+This software is licensed under the terms of the GNU General Public License v3.0. See the [LICENSE](./LICENSE) file.

pom.xml

@@ -5,11 +5,11 @@
 
 	<groupId>com.github.greg.junkietech.yaproxy</groupId>
 	<artifactId>yaproxy</artifactId>
-	<version>1.0-SNAPSHOT</version>
+	<version>1.0</version>
 	<packaging>jar</packaging>
 
 	<name>yaproxy</name>
-	<url>http://maven.apache.org</url>
+	<url>https://github.com/greg-junkietech/yaproxy</url>
 
 	<properties>
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
@@ -50,11 +50,6 @@
 			<artifactId>httpclient</artifactId>
 			<version>4.5.2</version>
 		</dependency>
-		<!-- <dependency>
-			<groupId>org.apache.httpcomponents</groupId>
-			<artifactId>httpcore</artifactId>
-			<version>4.4.5</version>
-		</dependency> -->
 	</dependencies>
 
 	<build>

src/main/java/com/github/greg/junkietech/yaproxy/RequestHandler.java

@@ -51,21 +51,26 @@ public void handle(HttpExchange exchange) {
                 exchange.getRequestMethod(), exchange.getRequestURI().toString(),
                 exchange.getRemoteAddress().toString(), reqHost);
         try {
+            ALoadBalancer<ServiceRoute> lb = serviceMap.get(reqHost);
             /* String contentType = exchange.getRequestHeaders().getFirst("Content-Type");
             if (contentType == null || !contentType.startsWith("application/json")) {
                 HttpIOUtil.writeResponse(exchange, "{'error':'Content-Type application/json is required'}",
                         HttpStatus.SC_BAD_REQUEST);
-            } else */ if (!serviceMap.containsKey(reqHost)) {
+            } else */ if (lb == null) {
                 HttpIOUtil.writeResponse(exchange, "{'error':'no service domain defined for host " + reqHost + "'}",
                         HttpStatus.SC_BAD_REQUEST);
             } else {
-                ALoadBalancer<ServiceRoute> lb = serviceMap.get(reqHost);
                 handleClientRequest(exchange, lb);
             }
         } catch (IOException e) {
             LOGGER.warn("IOException occurred while serving {} {} {} from {} with header Host '{}': {}",
                     exchange.getProtocol(), exchange.getRequestMethod(), exchange.getRequestURI().toString(),
                     exchange.getRemoteAddress().toString(), reqHost, e.getMessage());
+        } catch (RuntimeException e) {
+            LOGGER.warn("RuntimeException occurred while serving {} {} {} from {} with header Host '{}': {}",
+                    exchange.getProtocol(), exchange.getRequestMethod(), exchange.getRequestURI().toString(),
+                    exchange.getRemoteAddress().toString(), reqHost, e.getMessage());
+            LOGGER.warn("RuntimeException details", e);
         }
     }
 
@@ -119,7 +124,7 @@ private static void handleClientRequestFromDownstream(HttpExchange exchange, ALo
     private static ProxyRequest createProxyRequest(HttpExchange exchange, ServiceRoute svcRoute) {
         HttpRequest httpRequest;
 
-        // HTTTP/1.1 RFC 2616 section 4.3: https://tools.ietf.org/html/rfc2616
+        // HTTP/1.1 RFC 2616 section 4.3: https://tools.ietf.org/html/rfc2616
         // The presence of a message-body in a request is signaled by the
         // inclusion of a Content-Length or Transfer-Encoding header field in
         // the request's message-headers.
@@ -147,14 +152,13 @@ private static void handleServiceResponse(HttpResponse svcResponse, HttpExchange
         copyResponseHeaders(svcResponse.getAllHeaders(), exchange.getResponseHeaders());
 
         if (statusCode == HttpStatus.SC_NOT_MODIFIED) {
-            // HTTTP/1.1 RFC 2616 section 4.3: https://tools.ietf.org/html/rfc2616
+            // HTTP/1.1 RFC 2616 section 4.3: https://tools.ietf.org/html/rfc2616
             // All 1xx (informational), 204 (no content), and 304 (not modified) responses
             // MUST NOT include a message-body. All other responses do include a
             // message-body, although it MAY be of zero length.
             exchange.sendResponseHeaders(statusCode, 0);
         } else {
-            long contentLength = RequestHandler
-                    .getContentLength(svcResponse.getFirstHeader("Content-Length").getValue());
+            long contentLength = RequestHandler.getContentLength(svcResponse.getFirstHeader("Content-Length"));
             exchange.sendResponseHeaders(statusCode, contentLength);
             HttpEntity entity = svcResponse.getEntity();
             if (entity.isChunked()) {
@@ -170,7 +174,7 @@ private static void handleServiceResponseBody(HttpResponse svcResponse, HttpEnti
         OutputStream os = exchange.getResponseBody();
         int statusCode = svcResponse.getStatusLine().getStatusCode();
 
-        // see HTTTP/1.1 RFC 2616 section 14.9: https://tools.ietf.org/html/rfc2616#section-14.9
+        // see HTTP/1.1 RFC 2616 section 14.9: https://tools.ietf.org/html/rfc2616#section-14.9
         Header ccHeader = svcResponse.getFirstHeader(HEADER_CACHE_CONTROL);
         Matcher ccHeaderPatternMatcher;
         final String cachingLoginfo;
@@ -182,7 +186,6 @@ private static void handleServiceResponseBody(HttpResponse svcResponse, HttpEnti
             entity.writeTo(os);
         } else if ((ccHeaderPatternMatcher = Pattern.compile(" *(public, *)?(max-age|s-maxage)=(\\d+)")
                 .matcher(ccHeader.getValue())).matches()) {
-            // TODO cope with large content where content length exceeds int capacity
             byte[] content = handleCachingResponseBody(entity, lb, proxyRequest, contentLength, ccHeaderPatternMatcher,
                     svcResponse.getAllHeaders());
             cachingLoginfo = String.format("cached as supported %s", ccHeader);
@@ -203,6 +206,7 @@ private static void handleServiceResponseBody(HttpResponse svcResponse, HttpEnti
     private static byte[] handleCachingResponseBody(HttpEntity entity, ALoadBalancer<ServiceRoute> lb,
             ProxyRequest proxyRequest, long contentLength, Matcher ccHeaderPatternMatcher, Header[] responseHeaders)
             throws IOException {
+        // TODO cope with large content where content length exceeds int capacity (2'048 MB)
         ByteArrayOutputStream baos = new ByteArrayOutputStream((int)contentLength);
         entity.writeTo(baos);
         byte[] responseBody = baos.toByteArray();
@@ -214,9 +218,16 @@ private static byte[] handleCachingResponseBody(HttpEntity entity, ALoadBalancer
         return responseBody;
     }
 
-    private static long getContentLength(String contentLengthHeader) {
+    private static long getContentLength(Header contentLengthHeader) {
         if (contentLengthHeader != null) {
-            return Long.parseLong(contentLengthHeader);
+            return getContentLength(contentLengthHeader.getValue());
+        }
+        return -1L;
+    }
+
+    private static long getContentLength(String contentLengthHeaderValue) {
+        if (contentLengthHeaderValue != null) {
+            return Long.parseLong(contentLengthHeaderValue);
         }
         return -1L;
     }

src/main/java/com/github/greg/junkietech/yaproxy/YAProxy.java

@@ -42,7 +42,7 @@ public YAProxy(Configuration config) throws IOException {
         this.config = config;
         this.clearCacheService = Executors.newScheduledThreadPool(config.getProxy().getServices().size());
         this.serviceMap = initServiceMap();
-        this.server = initServer(serviceMap);
+        this.server = initServer();
         initShutdownHook();
     }
 
@@ -59,9 +59,9 @@ private void initShutdownHook() {
     }
 
     public void start() {
+        server.start();
         LOGGER.info("server listening on {}:{}...", config.getProxy().getListen().getAddress(),
                 config.getProxy().getListen().getPort());
-        server.start();
     }
 
     private Map<String, ALoadBalancer<ServiceRoute>> initServiceMap() {
@@ -98,6 +98,7 @@ private Map<String, ALoadBalancer<ServiceRoute>> initServiceMap() {
     private static HttpHost setupDownstreamProxy(HttpClientBuilder builder, EndPoint host, Service service,
             Proxy proxy) {
         String proxyHost = null;
+        HttpHost result = null;
         if (host.getDownstreamPoxy() != null) {
             proxyHost = host.getDownstreamPoxy();
         } else if (service.getDownstreamPoxy() != null) {
@@ -106,11 +107,10 @@ private static HttpHost setupDownstreamProxy(HttpClientBuilder builder, EndPoint
             proxyHost = proxy.getDownstreamPoxy();
         }
         if (proxyHost != null) {
-            HttpHost result = HttpHost.create(proxyHost);
+            result = HttpHost.create(proxyHost);
             builder.setProxy(result);
-            return result;
         }
-        return null;
+        return result;
     }
 
     private ALoadBalancer<ServiceRoute> createLoadBalancer(List<ServiceRoute> targetList, String serviceName) {
@@ -131,7 +131,7 @@ private ALoadBalancer<ServiceRoute> createLoadBalancer(List<ServiceRoute> target
         return result;
     }
 
-    private HttpServer initServer(final Map<String, ALoadBalancer<ServiceRoute>> serviceMap) throws IOException {
+    private HttpServer initServer() throws IOException {
         HttpServer result = HttpServer.create(new InetSocketAddress(config.getProxy().getListen().getAddress(),
                 config.getProxy().getListen().getPort()), 0);
         LOGGER.info("initializing server listening on {}:{}", config.getProxy().getListen().getAddress(),

src/main/java/com/github/greg/junkietech/yaproxy/util/HttpIOUtil.java

@@ -5,6 +5,7 @@
 
 import com.sun.net.httpserver.HttpExchange;
 
+@SuppressWarnings("restriction")
 public class HttpIOUtil {
     public static void writeResponse(HttpExchange exchange, String response, int code) throws IOException {
         writeResponse(exchange, response.getBytes(), code);