Handle slashes in pgw grouping label values. (#491)

Good base64 support was only added in Java 8,
we support back to Java 6 so this is a little unclean.

Signed-off-by: Brian Brazil <[email protected]>

Author: brian-brazil

simpleclient_pushgateway/src/main/java/io/prometheus/client/exporter/PushGateway.java

@@ -5,6 +5,7 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStreamWriter;
+import java.io.UnsupportedEncodingException;
 import java.net.HttpURLConnection;
 import java.net.InetAddress;
 import java.net.MalformedURLException;
@@ -15,6 +16,7 @@
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
+import javax.xml.bind.DatatypeConverter;
 
 import io.prometheus.client.Collector;
 import io.prometheus.client.CollectorRegistry;
@@ -79,7 +81,7 @@ public PushGateway(String address) {
    * @param serverBaseURL the base URL and optional context path of the Pushgateway server.
    */
   public PushGateway(URL serverBaseURL) {
-    this.gatewayBaseURL = URI.create(serverBaseURL.toString() + "/metrics/job/")
+    this.gatewayBaseURL = URI.create(serverBaseURL.toString() + "/metrics/")
       .normalize()
       .toString();
   }
@@ -275,11 +277,20 @@ public void delete(String job, String instance) throws IOException {
   }
 
   void doRequest(CollectorRegistry registry, String job, Map<String, String> groupingKey, String method) throws IOException {
-    String url = gatewayBaseURL + URLEncoder.encode(job, "UTF-8");
+    String url = gatewayBaseURL;
+    if (job.contains("/")) {
+      url += "job@base64/" + base64url(job);
+    } else {
+      url += "job/" + URLEncoder.encode(job, "UTF-8");
+    }
 
     if (groupingKey != null) {
       for (Map.Entry<String, String> entry: groupingKey.entrySet()) {
-        url += "/" + entry.getKey() + "/" + URLEncoder.encode(entry.getValue(), "UTF-8");
+        if (entry.getValue().contains("/")) {
+          url += "/" + entry.getKey() + "@base64/" + base64url(entry.getValue());
+        } else {
+          url += "/" + entry.getKey() + "/" + URLEncoder.encode(entry.getValue(), "UTF-8");
+        }
       }
     }
     HttpURLConnection connection = connectionFactory.create(url);
@@ -318,6 +329,15 @@ void doRequest(CollectorRegistry registry, String job, Map<String, String> group
     }
   }
 
+  private static String base64url(String v) {
+    // Per RFC4648 table 2. We support Java 6, and java.util.Base64 was only added in Java 8,
+    try {
+      return DatatypeConverter.printBase64Binary(v.getBytes("UTF-8")).replace("+", "-").replace("/", "_");
+    } catch (UnsupportedEncodingException e) {
+      throw new RuntimeException(e);  // Unreachable.
+    }
+  }
+
   /**
    * Returns a grouping key with the instance label set to the machine's IP address.
    * <p>

simpleclient_pushgateway/src/test/java/io/prometheus/client/exporter/PushGatewayTest.java

@@ -45,7 +45,7 @@ public void testInvalidURLThrowsRuntimeException() {
   public void testMultipleSlashesAreStrippedFromURL() {
     final PushGateway pushGateway = new PushGateway("example.com:1234/context///path//");
     Assert.assertEquals(
-        "http://example.com:1234/context/path/metrics/job/",
+        "http://example.com:1234/context/path/metrics/",
         pushGateway.gatewayBaseURL
     );
   }
@@ -106,9 +106,9 @@ public void testPushWithGroupingKeyWithSlashes() throws IOException {
     mockServerClient.when(
         request()
           .withMethod("PUT")
-          .withPath("/metrics/job/a%2Fb/l/v/l2/v%2F2")
+          .withPath("/metrics/job@base64/YS9i/l/v/l2@base64/75-_Lw==")
       ).respond(response().withStatusCode(202));
-    groupingKey.put("l2", "v/2");
+    groupingKey.put("l2", "\uF7FF/");
     pg.push(registry, "a/b", groupingKey);
   }
 
@@ -219,7 +219,7 @@ public void testOldPushWithSlashes() throws IOException {
     mockServerClient.when(
         request()
           .withMethod("PUT")
-          .withPath("/metrics/job/a%2Fb/instance/c%2Fd")
+          .withPath("/metrics/job@base64/YS9i/instance@base64/Yy9k")
       ).respond(response().withStatusCode(202));
     pg.push(registry, "a/b", "c/d");
   }