feat: add bearerToken builder to pushgateway exporter

docs/content/exporters/pushgateway.md

@@ -80,6 +80,21 @@ PushGateway pushGateway = PushGateway.builder()
 
 The `PushGatewayTestApp` in `integration-tests/it-pushgateway` has a complete example of this.
 
+Bearer token
+----------
+
+The [PushGateway](/client_java/api/io/prometheus/metrics/exporter/pushgateway/PushGateway.html) supports Bearer token authentication.
+
+```java
+PushGateway pushGateway = PushGateway.builder()
+    .job("example")
+    .bearerToken("my_token")
+    .build();
+```
+
+The `PushGatewayTestApp` in `integration-tests/it-pushgateway` has a complete example of this.
+
+
 SSL
 ---
 
@@ -100,4 +115,4 @@ The `PushGatewayTestApp` in `integration-tests/it-pushgateway` has a complete ex
 Configuration Properties
 ------------------------
 
-The [PushGateway](/client_java/api/io/prometheus/metrics/exporter/pushgateway/PushGateway.html) supports a couple of properties that can be configured at runtime. See [config](../../config/config).
+The [PushGateway](/client_java/api/io/prometheus/metrics/exporter/pushgateway/PushGateway.html) supports a couple of properties that can be configured at runtime. See [config](../../config/config).

integration-tests/it-pushgateway/src/main/java/io/prometheus/metrics/it/pushgateway/PushGatewayTestApp.java

@@ -128,4 +128,4 @@ private static void makeMetrics() {
                 .register();
         duration.set(0.5);
     }
-}
+}

prometheus-metrics-exporter-pushgateway/src/main/java/io/prometheus/metrics/exporter/pushgateway/PushGateway.java

@@ -278,6 +278,17 @@ public Builder basicAuth(String user, String password) {
             return this;
         }
 
+        /**
+         * Bearer token authorization when pushing to the Pushgateway.
+         */
+        public Builder bearerToken(String token) {
+            if (token == null)  {
+                throw new NullPointerException();
+            }
+            requestHeaders.put("Authorization", String.format("Bearer %s", token));
+            return this;
+        }
+
         /**
          * Specify if metrics should be pushed using HTTP or HTTPS. Default is HTTP.
          * Can be overwritten at runtime with the {@code io.prometheus.exporter.pushgateway.scheme} property.

prometheus-metrics-exporter-pushgateway/src/test/java/io/prometheus/metrics/exporter/pushgateway/BearerTokenPushGatewayTest.java

@@ -0,0 +1,48 @@
+package io.prometheus.metrics.exporter.pushgateway;
+
+import io.prometheus.metrics.core.metrics.Gauge;
+import io.prometheus.metrics.model.registry.PrometheusRegistry;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.mockserver.client.MockServerClient;
+import org.mockserver.junit.MockServerRule;
+
+import java.io.IOException;
+
+import static org.mockserver.model.HttpRequest.request;
+import static org.mockserver.model.HttpResponse.response;
+
+public class BearerTokenPushGatewayTest {
+
+    @Rule
+    public MockServerRule mockServerRule = new MockServerRule(this);
+    private MockServerClient mockServerClient;
+
+    PrometheusRegistry registry;
+    Gauge gauge;
+    PushGateway pushGateway;
+
+    @Before
+    public void setUp() {
+        registry = new PrometheusRegistry();
+        gauge = Gauge.builder().name("g").help("help").build();
+        pushGateway = PushGateway.builder()
+                .address("localhost:" + mockServerRule.getPort())
+                .bearerToken("xxx")
+                .registry(registry)
+                .job("j")
+                .build();
+    }
+
+    @Test
+    public void testAuthorizedPush() throws IOException {
+        mockServerClient.when(
+                request()
+                        .withMethod("PUT")
+                        .withHeader("Authorization", "Bearer xxx")
+                        .withPath("/metrics/job/j")
+        ).respond(response().withStatusCode(202));
+        pushGateway.push();
+    }
+}