Apply feedback and add more doc

Author: tlrx

modules/repository-url/build.gradle

@@ -1,5 +1,3 @@
-import org.elasticsearch.gradle.test.AntFixture
-
 /*
  * Licensed to Elasticsearch under one or more contributor
  * license agreements. See the NOTICE file distributed with
@@ -18,6 +16,7 @@ import org.elasticsearch.gradle.test.AntFixture
  * specific language governing permissions and limitations
  * under the License.
  */
+import org.elasticsearch.gradle.test.AntFixture
 
 esplugin {
     description 'Module for URL repository'
@@ -33,7 +32,7 @@ forbiddenApisTest {
 // This directory is shared between two URL repositories and one FS repository in YAML integration tests
 File repositoryDir = new File(project.buildDir, "shared-repository")
 
-/** A task to start the URLFixture that exposes the repositoryDir over HTTP **/
+/** A task to start the URLFixture which exposes the repositoryDir over HTTP **/
 task urlFixture(type: AntFixture) {
     doFirst {
         repositoryDir.mkdirs()
@@ -47,6 +46,6 @@ integTestCluster {
     dependsOn urlFixture
     // repositoryDir is used by a FS repository to create snapshots
     setting 'path.repo', "${repositoryDir.absolutePath}"
-    // repositoryDir is used by a URL repository to restore snapshots
+    // repositoryDir is used by two URL repositories to restore snapshots
     setting 'repositories.url.allowed_urls', "http://snapshot.test*,http://${ -> urlFixture.addressAndPort }"
 }

modules/repository-url/src/test/java/org/elasticsearch/repositories/url/RepositoryURLClientYamlTestSuiteIT.java

@@ -58,6 +58,13 @@ public static Iterable<Object[]> parameters() throws Exception {
         return ESClientYamlSuiteTestCase.createParameters();
     }
 
+    /**
+     * This method registers 3 snapshot/restore repositories:
+     * - repository-fs: this FS repository is used to create snapshots.
+     * - repository-url: this URL repository is used to restore snapshots created using the previous repository. It uses
+     * the URLFixture to restore snapshots over HTTP.
+     * - repository-file: similar as the previous repository but using a file:// prefix instead of http://.
+     **/
     @Before
     public void registerRepositories() throws IOException {
         Response clusterSettingsResponse = client().performRequest("GET", "/_cluster/settings?include_defaults=true" +

modules/repository-url/src/test/java/org/elasticsearch/repositories/url/URLFixture.java

@@ -31,6 +31,7 @@
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -44,7 +45,7 @@
 
 /**
  * This {@link URLFixture} exposes a filesystem directory over HTTP. It is used in repository-url
- * integration tests to expose a directory populated using a regular FS repository.
+ * integration tests to expose a directory created by a regular FS repository.
  */
 public class URLFixture {
 
@@ -130,7 +131,8 @@ public void handle(HttpExchange exchange) throws IOException {
                     response = new Response(RestStatus.FORBIDDEN, emptyMap(), "text/plain", new byte[0]);
                 }
             } else {
-                response = new Response(RestStatus.INTERNAL_SERVER_ERROR, emptyMap(), "text/plain", new byte[0]);
+                response = new Response(RestStatus.INTERNAL_SERVER_ERROR, emptyMap(), "text/plain",
+                    "Unsupported HTTP method".getBytes(StandardCharsets.UTF_8));
             }
             exchange.sendResponseHeaders(response.status.getStatus(), response.body.length);
             if (response.body.length > 0) {

modules/repository-url/src/test/resources/rest-api-spec/test/repository_url/10_basic.yml

@@ -1,4 +1,13 @@
 # Integration tests for repository-url
+#
+# This test is based on 3 repositories, all registered before this
+# test is executed. The repository-fs is used to create snapshots
+# in a shared directory on the filesystem. Then the test uses a URL
+# repository with a "http://" prefix to test the restore of the
+# snapshots. In order to do that it uses a URLFixture that exposes
+# the content of the shared directory over HTTP. A second URL
+# repository is used to test the snapshot restore but this time
+# with a "file://" prefix. 
 setup:
 
   # Ensure that the FS repository is registered, so we can create
@@ -103,7 +112,7 @@ teardown:
     - do:
         nodes.info: {}
 
-    - match:  { nodes.$master.modules.0.name: repository-url  }
+    - match: { nodes.$master.modules.0.name: repository-url }
 
 ---
 "Restore with repository-url using http://":

modules/repository-url/src/test/resources/rest-api-spec/test/repository_url/20_repository.yml

@@ -14,3 +14,18 @@
         repository: test_repo1
 
   - is_true : test_repo1
+
+---
+"Repository cannot be be registered":
+
+  - do:
+      catch: /doesn't match any of the locations specified by path.repo or repositories.url.allowed_urls/
+      snapshot.create_repository:
+        repository: test_repo2
+        body:
+          type: url
+          settings:
+            url: "http://snapshot.unknown"
+
+
+