Merge pull request #4 from kekru/feature/custom-host-header

option to send a host header different from the upstream server

README.md

@@ -7,11 +7,12 @@ Inspired by [robszumski/k8s-service-proxy](https://github.com/robszumski/k8s-ser
 
 ## Configuration
 
-Every proxy rule consist of three env variables:
+Every proxy rule consist of three or four env variables:
 
 + `RULE_1_MODE`: <mode>
 + `RULE_1_PATTERN`: <regex pattern> (see [nginx regex names](http://nginx.org/en/docs/http/server_names.html#regex_names))
 + `RULE_1_TARGET`: <target with usage of pattern variables>
++ `RULE_1_TARGET_HOST_HEADER`: <(Optional) modified host header, defaults to TARGET>
 
 Example:  
 
@@ -23,6 +24,7 @@ RULE_1_TARGET: 'https://$service.ab.example.com'
 RULE_2_MODE: 'HTTP'
 RULE_2_PATTERN: '(?<service>.+).xy.127-0-0-1.nip.io'
 RULE_2_TARGET: 'https://$service.xy.example.com'
+RULE_2_TARGET_HOST_HEADER: '$service.modified-host.example.com'
 ```
 
 This creates two rules.  
@@ -31,7 +33,8 @@ The following example requests will get the shown proxy actions:
 + `http://hello.ab.127-0-0-1.nip.io` will proxy pass to  
   `https://hello.ab.example.com`
 + `http://world.xy.127-0-0-1.nip.io` will proxy pass to  
-  `https://world.xy.example.com`
+  `https://world.xy.example.com`  
+  but send the host header `world.modified-host.example.com`
 
 > Currently only mode HTTP is implemented
 

script/createConfigs.sh

@@ -18,8 +18,9 @@ do
     eval mode='$RULE_'$ruleName'_MODE'
     eval pattern='$RULE_'$ruleName'_PATTERN'
     eval target='$RULE_'$ruleName'_TARGET'
+    eval targetHostHeader='$RULE_'$ruleName'_TARGET_HOST_HEADER'
 
-    echo "Configuring rule $ruleName, mode: $mode, pattern: $pattern, target: $target"
+    echo "Configuring rule $ruleName, mode: $mode, pattern: $pattern, target: $target, targetHostHeader: $targetHostHeader"
 
     if [[ "$mode" == "TLSPASS" ]]; then
       echo "MODE TLSPASS is not yet implemented"
@@ -43,7 +44,11 @@ do
       file="/data/configs/http/http-$ruleName.conf"
       cp /data/templates/HTTP.conf $file
       sed -i "s|PATTERN|$pattern|g" $file
-      sed -i "s|TARGET|$target|g" $file
+      sed -i "s|TARGET_HOST_ADDRESS|$target|g" $file
+      if [ -z "$targetHostHeader" ]; then
+        targetHostHeader="\$proxy_host"
+      fi
+      sed -i "s|TARGET_HOST_HEADER|$targetHostHeader|g" $file
       sed -i "s|DNS_RESOLVER|$DNS_RESOLVER|g" $file
     fi
 

templates/HTTP.conf

@@ -4,9 +4,10 @@ server {
 
     location / {
         resolver DNS_RESOLVER;
-        proxy_pass TARGET;
+        proxy_pass TARGET_HOST_ADDRESS;
+        proxy_set_header Host TARGET_HOST_HEADER;
 
-        # Replace TARGET in 303 redirects with current hostname and port (from clients request)
-        proxy_redirect TARGET $scheme://$http_host;
+        # Replace TARGET_HOST_ADDRESS in 303 redirects with current hostname and port (from clients request)
+        proxy_redirect TARGET_HOST_ADDRESS $scheme://$http_host;
     }
 }

test/pom.xml

@@ -30,7 +30,7 @@
     <dependency>
       <groupId>org.testcontainers</groupId>
       <artifactId>testcontainers</artifactId>
-      <version>1.14.2</version>
+      <version>1.15.2</version>
       <scope>test</scope>
     </dependency>
     <dependency>

test/src/test/java/de/kekru/patternproxy/test/IntegrationTest.java

@@ -5,6 +5,10 @@
 import static org.mockserver.model.HttpRequest.request;
 import static org.mockserver.model.HttpResponse.response;
 
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
 import org.junit.Test;
 import org.mockserver.client.MockServerClient;
 import org.mockserver.model.MediaType;
@@ -89,19 +93,60 @@ public void testRedirectReaplacesWithClientsRequestHostHeader() {
     }
   }
 
+  @Test
+  public void testUsingDifferentHostHeaders() {
+    Map<String, String> additionalEnv = new HashMap<>();
+    additionalEnv.put("RULE_1_TARGET_HOST_HEADER", "something-strange-$service-that-does-not-resolve");
+    try (
+        Network network = createNetwork();
+        GenericContainer mockServerContainer = createMockServer(network);
+        GenericContainer patternProxyContainer = createPatternProxy(network, additionalEnv);
+    ) {
+      mockServerContainer.start();
+      patternProxyContainer.start();
+      patternProxyMappedPort = patternProxyContainer.getMappedPort(80);
+      mockServerMappedPort = mockServerContainer.getMappedPort(1090);
+      patternProxyContainer.followOutput(new Slf4jLogConsumer(LOG_PATTERN_PROXY));
+
+
+      mockServerClient = new MockServerClient("localhost", mockServerMappedPort);
+      mockServerClient
+          .when(request()
+              .withMethod("GET")
+              .withHeader("Host", "something-strange-abc-that-does-not-resolve")
+              .withPath("/something"))
+          .respond(response()
+              .withStatusCode(200)
+              .withContentType(MediaType.JSON_UTF_8)
+              .withBody("{ \"message\": \"It Works, requested was something-strange-abc-that-does-not-resolve\" }"));
+
+      given()
+          .when()
+          .redirects().follow(false)
+          .get("http://abc.pp.127-0-0-1.nip.io:" + patternProxyMappedPort + "/something")
+          .then()
+          .body("message", equalTo("It Works, requested was something-strange-abc-that-does-not-resolve"));
+    }
+  }
+
 
   private Network createNetwork() {
     return Network.newNetwork();
   }
 
   private GenericContainer createPatternProxy(Network network) {
+    return createPatternProxy(network, Collections.emptyMap());
+  }
+
+  private GenericContainer createPatternProxy(Network network, Map<String, String> additionalEnv) {
 
     GenericContainer container = new GenericContainer("kekru/pattern-proxy:temp-for-unittests")
         .withNetwork(network)
         .withExposedPorts(80).withEnv("RULE_1_MODE", "HTTP")
         .withEnv("RULE_1_PATTERN", "(?<service>.+).pp.127-0-0-1.nip.io")
         .withEnv("RULE_1_TARGET", "http://$service.mock-server:1090")
         .withEnv("DNS_RESOLVER", "127.0.0.11") // Internal Docker Network Resolver
+        .withEnv(additionalEnv)
         ;
     return container;
   }