Support HTTP headers on HttpWaitStrategy (#2549)

This enables webservers that depend on headers for healthchecks to be
able to correctly be queried by the HttpWaitStrategy.

Co-authored-by: Sergei Egorov <bsideup@gmail.com>

core/src/main/java/org/testcontainers/containers/wait/strategy/HttpWaitStrategy.java

@@ -2,6 +2,8 @@
 
 import com.google.common.base.Strings;
 import com.google.common.io.BaseEncoding;
+import java.util.HashMap;
+import java.util.Map;
 import lombok.extern.slf4j.Slf4j;
 import org.rnorth.ducttape.TimeoutException;
 import org.testcontainers.containers.ContainerLaunchException;
@@ -40,6 +42,7 @@ public class HttpWaitStrategy extends AbstractWaitStrategy {
     private boolean tlsEnabled;
     private String username;
     private String password;
+    private final Map<String, String> headers = new HashMap<>();
     private Predicate<String> responsePredicate;
     private Predicate<Integer> statusCodePredicate = null;
     private Optional<Integer> livenessPort = Optional.empty();
@@ -122,6 +125,27 @@ public HttpWaitStrategy withBasicCredentials(String username, String password) {
         return this;
     }
 
+    /**
+     * Add a custom HTTP Header to the call.
+     * @param name The HTTP Header name
+     * @param value The HTTP Header value
+     * @return this
+     */
+    public HttpWaitStrategy withHeader(String name, String value) {
+        this.headers.put(name, value);
+        return this;
+    }
+
+    /**
+     * Add multiple custom HTTP Headers to the call.
+     * @param headers Headers map of name/value
+     * @return this
+     */
+    public HttpWaitStrategy withHeaders(Map<String, String> headers) {
+        this.headers.putAll(headers);
+        return this;
+    }
+
     /**
      * Set the HTTP connections read timeout.
      *
@@ -191,6 +215,8 @@ protected void waitUntilReady() {
                             connection.setUseCaches(false);
                         }
 
+                        // Add user configured headers
+                        this.headers.forEach(connection::setRequestProperty);
                         connection.setRequestMethod(method);
                         connection.connect();
 

core/src/test/java/org/testcontainers/junit/wait/strategy/HttpWaitStrategyTest.java

@@ -1,8 +1,13 @@
 package org.testcontainers.junit.wait.strategy;
 
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.junit.Assert.assertThat;
+
+import java.util.HashMap;
 import org.jetbrains.annotations.NotNull;
 import org.junit.Test;
 import org.rnorth.ducttape.RetryCountExceededException;
+import org.testcontainers.containers.GenericContainer;
 import org.testcontainers.containers.wait.strategy.HttpWaitStrategy;
 
 import java.time.Duration;
@@ -30,6 +35,28 @@ public void testWaitUntilReadyWithSuccess() {
         waitUntilReadyAndSucceed(createShellCommand("200 OK", GOOD_RESPONSE_BODY));
     }
 
+    /**
+     * Ensures that HTTP requests made with the HttpWaitStrategy can be enriched with user defined headers,
+     * although the test web server does not depend on the header to response with a 200, by checking the
+     * logs we can ensure the HTTP request was correctly sent.
+     */
+    @Test
+    public void testWaitUntilReadyWithSuccessWithCustomHeaders() {
+        HashMap<String, String> headers = new HashMap<>();
+        headers.put("baz", "boo");
+        GenericContainer container = startContainerWithCommand(createShellCommand("200 OK", GOOD_RESPONSE_BODY),
+            createHttpWaitStrategy(ready)
+                .withHeader("foo", "bar")
+                .withHeaders(headers)
+        );
+        waitUntilReadyAndSucceed(container);
+
+        String logs = container.getLogs();
+
+        assertThat(logs, containsString("foo: bar"));
+        assertThat(logs, containsString("baz: boo"));
+    }
+
     /**
      * Expects that the WaitStrategy returns successfully after receiving an HTTP 401 response from the container.
      * This 401 response is checked with a lambda using {@link HttpWaitStrategy#forStatusCodeMatching(Predicate)}