Move metrics handler utilities to new package in container-core

5 files changed, 171 insertions, 0 deletions

diff --git a/container-core/src/main/java/com/yahoo/container/handler/metrics/ErrorResponse.java b/container-core/src/main/java/com/yahoo/container/handler/metrics/ErrorResponse.java
new file mode 100644
index 00000000000..321f7b3994a
--- /dev/null
+++ b/container-core/src/main/java/com/yahoo/container/handler/metrics/ErrorResponse.java
@@ -0,0 +1,32 @@
+// Copyright 2020 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.container.handler.metrics;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import java.util.Map;
+import java.util.logging.Logger;
+
+import static java.util.logging.Level.WARNING;
+
+/**
+ * @author gjoranv
+ */
+public class ErrorResponse extends JsonResponse {
+    private static Logger log = Logger.getLogger(ErrorResponse.class.getName());
+
+    private static ObjectMapper objectMapper = new ObjectMapper();
+
+    public ErrorResponse(int code, String message) {
+        super(code, asErrorJson(message));
+    }
+
+    static String asErrorJson(String message) {
+        try {
+            return objectMapper.writeValueAsString(Map.of("error", message));
+        } catch (JsonProcessingException e) {
+            log.log(WARNING, "Could not encode error message to json:", e);
+            return "Could not encode error message to json, check the log for details.";
+        }
+    }
+}
diff --git a/container-core/src/main/java/com/yahoo/container/handler/metrics/HttpHandlerBase.java b/container-core/src/main/java/com/yahoo/container/handler/metrics/HttpHandlerBase.java
new file mode 100644
index 00000000000..92840cee48f
--- /dev/null
+++ b/container-core/src/main/java/com/yahoo/container/handler/metrics/HttpHandlerBase.java
@@ -0,0 +1,78 @@
+// Copyright 2020 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.container.handler.metrics;
+
+import com.yahoo.container.jdisc.HttpRequest;
+import com.yahoo.container.jdisc.HttpResponse;
+import com.yahoo.container.jdisc.ThreadedHttpRequestHandler;
+import com.yahoo.restapi.Path;
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.net.URI;
+import java.util.List;
+import java.util.Optional;
+import java.util.concurrent.Executor;
+
+import static com.yahoo.jdisc.Response.Status.INTERNAL_SERVER_ERROR;
+import static com.yahoo.jdisc.Response.Status.METHOD_NOT_ALLOWED;
+import static com.yahoo.jdisc.Response.Status.NOT_FOUND;
+import static com.yahoo.jdisc.Response.Status.OK;
+import static com.yahoo.jdisc.http.HttpRequest.Method.GET;
+import static java.util.logging.Level.WARNING;
+
+/**
+ * @author gjoranv
+ */
+public abstract class HttpHandlerBase extends ThreadedHttpRequestHandler {
+
+    protected HttpHandlerBase(Executor executor) {
+        super(executor);
+    }
+
+    protected abstract Optional<HttpResponse> doHandle(URI requestUri, Path apiPath, String consumer);
+
+    @Override
+    public final HttpResponse handle(HttpRequest request) {
+        if (request.getMethod() != GET) return new JsonResponse(METHOD_NOT_ALLOWED, "Only GET is supported");
+
+        Path path = new Path(request.getUri());
+
+        return doHandle(request.getUri(), path, getConsumer(request))
+                .orElse(new ErrorResponse(NOT_FOUND, "No content at given path"));
+    }
+
+    private String getConsumer(HttpRequest request) {
+        return request.getProperty("consumer");
+    }
+
+    protected JsonResponse resourceListResponse(URI requestUri, List<String> resources) {
+        try {
+            return new JsonResponse(OK, resourceList(requestUri, resources));
+        } catch (JSONException e) {
+            log.log(WARNING, "Bad JSON construction in generated resource list for " + requestUri.getPath(), e);
+            return new ErrorResponse(INTERNAL_SERVER_ERROR,
+                                     "An error occurred when generating the list of api resources.");
+        }
+    }
+
+    // TODO: Use jackson with a "Resources" class instead of JSONObject
+    private static String resourceList(URI requestUri, List<String> resources) throws JSONException {
+        int port = requestUri.getPort();
+        String host = requestUri.getHost();
+        StringBuilder base = new StringBuilder("http://");
+        base.append(host);
+        if (port >= 0) {
+            base.append(":").append(port);
+        }
+        String uriBase = base.toString();
+        JSONArray linkList = new JSONArray();
+        for (String api : resources) {
+            JSONObject resource = new JSONObject();
+            resource.put("url", uriBase + api);
+            linkList.put(resource);
+        }
+        return new JSONObject().put("resources", linkList).toString(4);
+    }
+
+}
diff --git a/container-core/src/main/java/com/yahoo/container/handler/metrics/JsonResponse.java b/container-core/src/main/java/com/yahoo/container/handler/metrics/JsonResponse.java
new file mode 100644
index 00000000000..def06ce9de3
--- /dev/null
+++ b/container-core/src/main/java/com/yahoo/container/handler/metrics/JsonResponse.java
@@ -0,0 +1,30 @@
+// Copyright 2020 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.container.handler.metrics;
+
+import com.yahoo.container.jdisc.HttpResponse;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.nio.charset.Charset;
+
+/**
+ * @author gjoranv
+ */
+public class JsonResponse extends HttpResponse {
+    private final byte[] data;
+
+    public JsonResponse(int code, String data) {
+        super(code);
+        this.data = data.getBytes(Charset.forName(DEFAULT_CHARACTER_ENCODING));
+    }
+
+    @Override
+    public String getContentType() {
+        return "application/json";
+    }
+
+    @Override
+    public void render(OutputStream outputStream) throws IOException {
+        outputStream.write(data);
+    }
+}
diff --git a/container-core/src/main/java/com/yahoo/container/handler/metrics/package-info.java b/container-core/src/main/java/com/yahoo/container/handler/metrics/package-info.java
new file mode 100644
index 00000000000..031886afc94
--- /dev/null
+++ b/container-core/src/main/java/com/yahoo/container/handler/metrics/package-info.java
@@ -0,0 +1,6 @@
+// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+/** Exported config package */
+@ExportPackage
+package com.yahoo.container.handler.metrics;
+
+import com.yahoo.osgi.annotation.ExportPackage;
diff --git a/container-core/src/test/java/com/yahoo/container/handler/metrics/ErrorResponseTest.java b/container-core/src/test/java/com/yahoo/container/handler/metrics/ErrorResponseTest.java
new file mode 100644
index 00000000000..882f9044dce
--- /dev/null
+++ b/container-core/src/test/java/com/yahoo/container/handler/metrics/ErrorResponseTest.java
@@ -0,0 +1,25 @@
+// Copyright 2020 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.container.handler.metrics;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * @author gjoranv
+ */
+public class ErrorResponseTest {
+
+    @Test
+    public void error_message_is_wrapped_in_json_object() {
+        var json =  ErrorResponse.asErrorJson("bad");
+        assertEquals("{\"error\":\"bad\"}", json);
+    }
+
+    @Test
+    public void quotes_are_escaped() {
+        var json =  ErrorResponse.asErrorJson("Message \" with \" embedded quotes.");
+        assertEquals("{\"error\":\"Message \\\" with \\\" embedded quotes.\"}", json);
+    }
+
+}