More customizable reverse proxy, with built-in configuration.

rapidoid-commons/src/main/java/org/rapidoid/config/Conf.java

@@ -58,6 +58,7 @@ public Config map(String name) throws Exception {
 	public static final Config APP = section("app");
 	public static final Config GUI = section("gui");
 	public static final Config HTTP = section("http");
+	public static final Config REVERSE_PROXY = section("reverse-proxy");
 	public static final Config NET = section("net");
 	public static final Config ON = section("on");
 	public static final Config ADMIN = section("admin");

rapidoid-commons/src/main/resources/built-in-config.yml

@@ -117,6 +117,13 @@ http:
     server: true
     contentType: true
 
+reverse-proxy:
+  timeout: 10000
+  retryDelay: 300
+  maxConnections: 100
+  maxConnectionsPerRoute: 100
+  reuseConnections: true
+
 token:
   ttl: 0 # unlimited
 

rapidoid-http-server/src/main/java/org/rapidoid/reverseproxy/AbstractReverseProxyBean.java

@@ -3,6 +3,8 @@
 import org.rapidoid.RapidoidThing;
 import org.rapidoid.annotation.Authors;
 import org.rapidoid.annotation.Since;
+import org.rapidoid.config.Conf;
+import org.rapidoid.config.Config;
 import org.rapidoid.http.HttpClient;
 import org.rapidoid.util.LazyInit;
 
@@ -32,11 +34,17 @@
 @Since("5.2.0")
 public abstract class AbstractReverseProxyBean<T> extends RapidoidThing {
 
-	private volatile boolean reuseConnections = true;
+	private static final Config CFG = Conf.REVERSE_PROXY;
 
-	private volatile int maxConnTotal = 100;
+	private volatile long retryDelay = CFG.entry("retryDelay").or(300);
 
-	private volatile int maxConnPerRoute = 100;
+	private volatile long timeout = CFG.entry("timeout").or(10000);
+
+	private volatile boolean reuseConnections = CFG.entry("reuseConnections").or(true);
+
+	private volatile int maxConnections = CFG.entry("maxConnections").or(100);
+
+	private volatile int maxConnectionsPerRoute = CFG.entry("maxConnectionsPerRoute").or(100);
 
 	private final LazyInit<HttpClient> client = new LazyInit<HttpClient>(new Callable<HttpClient>() {
 		@Override
@@ -61,22 +69,40 @@ public T reuseConnections(boolean reuseConnections) {
 		return me();
 	}
 
-	public int maxConnTotal() {
-		return maxConnTotal;
+	public long retryDelay() {
+		return retryDelay;
 	}
 
-	public T maxConnTotal(int maxConnTotal) {
-		this.maxConnTotal = maxConnTotal;
-		return me();
+	public AbstractReverseProxyBean retryDelay(int retryDelay) {
+		this.retryDelay = retryDelay;
+		return this;
 	}
 
-	public int maxConnPerRoute() {
-		return maxConnPerRoute;
+	public long timeout() {
+		return timeout;
 	}
 
-	public T maxConnPerRoute(int maxConnPerRoute) {
-		this.maxConnPerRoute = maxConnPerRoute;
-		return me();
+	public AbstractReverseProxyBean timeout(int timeout) {
+		this.timeout = timeout;
+		return this;
+	}
+
+	public int maxConnections() {
+		return maxConnections;
+	}
+
+	public AbstractReverseProxyBean maxConnections(int maxConnections) {
+		this.maxConnections = maxConnections;
+		return this;
+	}
+
+	public int maxConnectionsPerRoute() {
+		return maxConnectionsPerRoute;
+	}
+
+	public AbstractReverseProxyBean maxConnectionsPerRoute(int maxConnectionsPerRoute) {
+		this.maxConnectionsPerRoute = maxConnectionsPerRoute;
+		return this;
 	}
 
 	public HttpClient client() {

rapidoid-http-server/src/main/java/org/rapidoid/reverseproxy/ReverseProxy.java

@@ -8,6 +8,7 @@
 import org.rapidoid.job.Jobs;
 import org.rapidoid.log.LogLevel;
 import org.rapidoid.u.U;
+import org.rapidoid.util.Msc;
 
 import java.io.IOException;
 import java.net.ConnectException;
@@ -37,10 +38,6 @@
 @Since("5.2.0")
 public class ReverseProxy extends AbstractReverseProxyBean<ReverseProxy> implements ReqRespHandler {
 
-	private static final int RETRY_AFTER_MS = 300;
-
-	private static final int TIMEOUT_MS = 10000;
-
 	private final ProxyMapping mapping;
 
 	public ReverseProxy(ProxyMapping mapping) {
@@ -64,10 +61,11 @@ protected ProxyMapping findMapping(Req req) {
 		return mapping; // customizable for more complex logic
 	}
 
-	protected void process(final Req req, final Resp resp, final ProxyMapping mapping, final int attempts, final long since) {
+	private void process(final Req req, final Resp resp, final ProxyMapping mapping, final int attempts, final long since) {
 		final String targetUrl = mapping.getTargetUrl(req);
 
-		Map<String, String> headers = req.headers();
+		Map<String, String> headers = U.map(req.headers());
+
 		headers.remove("transfer-encoding");
 		headers.remove("content-length");
 
@@ -107,12 +105,12 @@ public void onDone(HttpResp result, Throwable error) {
 			});
 	}
 
-	protected void handleError(Throwable error, final Req req, final Resp resp, final ProxyMapping mapping, final int attempts, final long since) {
+	private void handleError(Throwable error, final Req req, final Resp resp, final ProxyMapping mapping, final int attempts, final long since) {
 		if (error instanceof ConnectException || error instanceof IOException) {
 
-			if (HttpUtils.isGetReq(req) && (U.time() - since < TIMEOUT_MS)) {
+			if (HttpUtils.isGetReq(req) && !Msc.timedOut(since, timeout())) {
 
-				Jobs.after(RETRY_AFTER_MS).milliseconds(new Runnable() {
+				Jobs.after(retryDelay()).milliseconds(new Runnable() {
 					@Override
 					public void run() {
 						process(req, resp, mapping, attempts + 1, since);
@@ -134,8 +132,8 @@ protected HttpClient createClient() {
 		return HTTP.client()
 			.reuseConnections(reuseConnections())
 			.keepCookies(false)
-			.maxConnTotal(maxConnTotal())
-			.maxConnPerRoute(maxConnPerRoute());
+			.maxConnTotal(maxConnections())
+			.maxConnPerRoute(maxConnectionsPerRoute());
 	}
 
 }

rapidoid-http-server/src/main/java/org/rapidoid/reverseproxy/ReverseProxyMapDSL.java

@@ -6,6 +6,7 @@
 import org.rapidoid.log.Log;
 import org.rapidoid.setup.On;
 import org.rapidoid.setup.OnRoute;
+import org.rapidoid.setup.Setup;
 import org.rapidoid.u.U;
 
 import java.util.List;
@@ -59,15 +60,15 @@ public ReverseProxyMapDSL to(List<String> upstreams) {
 		return this;
 	}
 
-	public ReverseProxy add() {
+	public ReverseProxy addTo(Setup setup) {
 		Log.info("!Reverse proxy mapping", "!uriPrefix", uriPrefix, "!upstreams", upstreams);
 
 		ReverseProxy proxy = createReverseProxy();
 
 		U.must(uriPrefix.startsWith("/"), "The URI prefix must start with '/'");
 
 		String path = uriPrefix.equals("/") ? "/*" : uriPrefix + "/*";
-		OnRoute route = On.any(path);
+		OnRoute route = setup.any(path);
 
 		if (roles != null) route.roles(roles);
 		if (cacheTTL != null) route.cacheTTL(cacheTTL);
@@ -78,6 +79,10 @@ public ReverseProxy add() {
 		return proxy;
 	}
 
+	public ReverseProxy add() {
+		return addTo(On.setup());
+	}
+
 	private ReverseProxy createReverseProxy() {
 		List<ProxyUpstream> proxyUpstreams = U.list();