Decouple flags REST API from config server

20 files changed, 261 insertions, 136 deletions

diff --git a/configserver-flags/src/main/java/com/yahoo/vespa/configserver/flags/ConfigServerFlagSource.java b/configserver-flags/src/main/java/com/yahoo/vespa/configserver/flags/ConfigServerFlagSource.java
index b1ffc05e70c..90709951dec 100644
--- a/configserver-flags/src/main/java/com/yahoo/vespa/configserver/flags/ConfigServerFlagSource.java
+++ b/configserver-flags/src/main/java/com/yahoo/vespa/configserver/flags/ConfigServerFlagSource.java
@@ -5,6 +5,7 @@ import com.google.inject.Inject;
 import com.yahoo.vespa.configserver.flags.db.BootstrapFlagSource;
 import com.yahoo.vespa.configserver.flags.db.ZooKeeperFlagSource;
 import com.yahoo.vespa.flags.OrderedFlagSource;
+import com.yahoo.vespa.flags.persistence.FlagsDb;
 
 import java.nio.file.FileSystem;
 import java.nio.file.FileSystems;
diff --git a/configserver-flags/src/main/java/com/yahoo/vespa/configserver/flags/FlagsDb.java b/configserver-flags/src/main/java/com/yahoo/vespa/configserver/flags/FlagsDb.java
deleted file mode 100644
index 2c29ae0b818..00000000000
--- a/configserver-flags/src/main/java/com/yahoo/vespa/configserver/flags/FlagsDb.java
+++ /dev/null
@@ -1,25 +0,0 @@
-// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-package com.yahoo.vespa.configserver.flags;
-
-import com.yahoo.vespa.flags.FlagId;
-import com.yahoo.vespa.flags.json.FlagData;
-
-import java.util.Map;
-import java.util.Optional;
-
-/**
- * @author hakonhall
- */
-public interface FlagsDb {
-    /** Get the String value of the flag. */
-    Optional<FlagData> getValue(FlagId flagId);
-
-    /** Set the String value of the flag. */
-    void setValue(FlagId flagId, FlagData data);
-
-    /** Remove the flag value if it exists. */
-    void removeValue(FlagId flagId);
-
-    /** Get all flags that have been set. */
-    Map<FlagId, FlagData> getAllFlags();
-}
diff --git a/configserver-flags/src/main/java/com/yahoo/vespa/configserver/flags/db/ZooKeeperFlagSource.java b/configserver-flags/src/main/java/com/yahoo/vespa/configserver/flags/db/ZooKeeperFlagSource.java
index 4a9d604b4bd..e6ab3f5b387 100644
--- a/configserver-flags/src/main/java/com/yahoo/vespa/configserver/flags/db/ZooKeeperFlagSource.java
+++ b/configserver-flags/src/main/java/com/yahoo/vespa/configserver/flags/db/ZooKeeperFlagSource.java
@@ -1,7 +1,7 @@
 // Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.configserver.flags.db;
 
-import com.yahoo.vespa.configserver.flags.FlagsDb;
+import com.yahoo.vespa.flags.persistence.FlagsDb;
 import com.yahoo.vespa.flags.FetchVector;
 import com.yahoo.vespa.flags.FlagId;
 import com.yahoo.vespa.flags.FlagSource;
diff --git a/configserver-flags/src/test/java/com/yahoo/vespa/configserver/flags/ConfigServerFlagSourceTest.java b/configserver-flags/src/test/java/com/yahoo/vespa/configserver/flags/ConfigServerFlagSourceTest.java
index d0d1d61628c..b2f891326fc 100644
--- a/configserver-flags/src/test/java/com/yahoo/vespa/configserver/flags/ConfigServerFlagSourceTest.java
+++ b/configserver-flags/src/test/java/com/yahoo/vespa/configserver/flags/ConfigServerFlagSourceTest.java
@@ -7,6 +7,7 @@ import com.yahoo.vespa.flags.FetchVector;
 import com.yahoo.vespa.flags.FlagId;
 import com.yahoo.vespa.flags.Flags;
 import com.yahoo.vespa.flags.RawFlag;
+import com.yahoo.vespa.flags.persistence.FlagsDb;
 import com.yahoo.vespa.test.file.TestFileSystem;
 import org.junit.After;
 import org.junit.Before;
@@ -103,4 +104,4 @@ public class ConfigServerFlagSourceTest {
         assertFalse(rawFlag2.isPresent());
         verify(flagsDb, times(1)).getValue(flagId2);
     }
-}
\ No newline at end of file
+}
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/http/flags/V1Response.java b/configserver/src/main/java/com/yahoo/vespa/config/server/http/flags/V1Response.java
deleted file mode 100644
index 3594c801ca8..00000000000
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/http/flags/V1Response.java
+++ /dev/null
@@ -1,34 +0,0 @@
-// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-package com.yahoo.vespa.config.server.http.flags;
-
-import com.yahoo.jdisc.Response;
-import com.yahoo.slime.Cursor;
-import com.yahoo.slime.Slime;
-import com.yahoo.text.Utf8;
-import com.yahoo.vespa.config.SlimeUtils;
-import com.yahoo.vespa.config.server.http.HttpConfigResponse;
-import com.yahoo.vespa.config.server.http.StaticResponse;
-
-import java.util.Arrays;
-import java.util.List;
-
-import static com.yahoo.yolean.Exceptions.uncheck;
-
-/**
- * @author hakonhall
- */
-public class V1Response extends StaticResponse {
-    public V1Response(String flagsV1Uri, String... names) {
-        super(Response.Status.OK, HttpConfigResponse.JSON_CONTENT_TYPE, generateBody(flagsV1Uri, Arrays.asList(names)));
-    }
-
-    private static String generateBody(String flagsV1Uri, List<String> names) {
-        Slime slime = new Slime();
-        Cursor root = slime.setObject();
-        names.forEach(name -> {
-            Cursor data = root.setObject(name);
-            data.setString("url", flagsV1Uri + "/" + name);
-        });
-        return Utf8.toString(uncheck(() -> SlimeUtils.toJsonBytes(slime)));
-    }
-}
diff --git a/configserver/src/main/resources/configserver-app/services.xml b/configserver/src/main/resources/configserver-app/services.xml
index cfacd6ff8c9..b429e220c33 100644
--- a/configserver/src/main/resources/configserver-app/services.xml
+++ b/configserver/src/main/resources/configserver-app/services.xml
@@ -54,7 +54,7 @@
     <preprocess:include file='model-integration.xml' required='true' />
 
     <component id="com.yahoo.vespa.configserver.flags.ConfigServerFlagSource" bundle="configserver-flags"/>
-    <component id="com.yahoo.vespa.configserver.flags.db.FlagsDbImpl" bundle="configserver-flags"/>
+    <component id="com.yahoo.vespa.flags.persistence.FlagsDb" bundle="flags"/>
 
     <preprocess:include file='metrics-packets.xml' required='false' />
     <preprocess:include file='container.xml' required='false' />
@@ -92,10 +92,6 @@
     <handler id='com.yahoo.vespa.config.server.http.status.StatusHandler' bundle='configserver'>
       <binding>http://*/status</binding>
     </handler>
-    <handler id='com.yahoo.vespa.config.server.http.flags.FlagsHandler' bundle='configserver'>
-      <binding>http://*/flags/v1</binding>
-      <binding>http://*/flags/v1/*</binding>
-    </handler>
     <handler id='com.yahoo.vespa.config.server.http.v2.TenantHandler' bundle='configserver'>
       <binding>http://*/application/v2/tenant/</binding>
       <binding>http://*/application/v2/tenant/*</binding>
diff --git a/flags/pom.xml b/flags/pom.xml
index c1e9eca20ab..7ef082cc1bc 100644
--- a/flags/pom.xml
+++ b/flags/pom.xml
@@ -59,7 +59,18 @@
             <classifier>no_aop</classifier>
             <scope>provided</scope>
         </dependency>
-
+        <dependency>
+            <groupId>com.yahoo.vespa</groupId>
+            <artifactId>container-dev</artifactId>
+            <version>${project.version}</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.yahoo.vespa</groupId>
+            <artifactId>zkfacade</artifactId>
+            <version>${project.version}</version>
+            <scope>provided</scope>
+        </dependency>
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/http/flags/DefinedFlag.java b/flags/src/main/java/com/yahoo/vespa/flags/http/DefinedFlag.java
index 92397fc84a7..8234e9df725 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/http/flags/DefinedFlag.java
+++ b/flags/src/main/java/com/yahoo/vespa/flags/http/DefinedFlag.java
@@ -1,12 +1,11 @@
 // Copyright 2019 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-package com.yahoo.vespa.config.server.http.flags;
+package com.yahoo.vespa.flags.http;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ArrayNode;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 import com.yahoo.container.jdisc.HttpResponse;
 import com.yahoo.jdisc.Response;
-import com.yahoo.vespa.config.server.http.HttpConfigResponse;
 import com.yahoo.vespa.flags.FlagDefinition;
 import com.yahoo.vespa.flags.json.DimensionHelper;
 
@@ -42,6 +41,7 @@ public class DefinedFlag extends HttpResponse {
 
     @Override
     public String getContentType() {
-        return HttpConfigResponse.JSON_CONTENT_TYPE;
+        return "application/json";
     }
+
 }
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/http/flags/DefinedFlags.java b/flags/src/main/java/com/yahoo/vespa/flags/http/DefinedFlags.java
index 9604c51ee4b..e1db7dda6e0 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/http/flags/DefinedFlags.java
+++ b/flags/src/main/java/com/yahoo/vespa/flags/http/DefinedFlags.java
@@ -1,11 +1,10 @@
 // Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-package com.yahoo.vespa.config.server.http.flags;
+package com.yahoo.vespa.flags.http;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 import com.yahoo.container.jdisc.HttpResponse;
 import com.yahoo.jdisc.Response;
-import com.yahoo.vespa.config.server.http.HttpConfigResponse;
 import com.yahoo.vespa.flags.FlagDefinition;
 
 import java.io.IOException;
@@ -18,8 +17,7 @@ import java.util.List;
  */
 public class DefinedFlags extends HttpResponse {
     private static ObjectMapper mapper = new ObjectMapper();
-    private static final Comparator<FlagDefinition> sortByFlagId =
-            (left, right) -> left.getUnboundFlag().id().compareTo(right.getUnboundFlag().id());
+    private static final Comparator<FlagDefinition> sortByFlagId = Comparator.comparing(flagDefinition -> flagDefinition.getUnboundFlag().id());
 
     private final List<FlagDefinition> flags;
 
@@ -40,6 +38,6 @@ public class DefinedFlags extends HttpResponse {
 
     @Override
     public String getContentType() {
-        return HttpConfigResponse.JSON_CONTENT_TYPE;
+        return "application/json";
     }
 }
diff --git a/flags/src/main/java/com/yahoo/vespa/flags/http/ErrorResponse.java b/flags/src/main/java/com/yahoo/vespa/flags/http/ErrorResponse.java
new file mode 100644
index 00000000000..969903093a4
--- /dev/null
+++ b/flags/src/main/java/com/yahoo/vespa/flags/http/ErrorResponse.java
@@ -0,0 +1,66 @@
+// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.flags.http;
+
+import com.yahoo.slime.Cursor;
+import com.yahoo.slime.Slime;
+
+import static com.yahoo.jdisc.Response.Status.BAD_REQUEST;
+import static com.yahoo.jdisc.Response.Status.FORBIDDEN;
+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.UNAUTHORIZED;
+
+/**
+ * A HTTP JSON response containing an error code and a message
+ *
+ * @author bratseth
+ */
+public class ErrorResponse extends SlimeJsonResponse {
+
+    public enum errorCodes {
+        NOT_FOUND,
+        BAD_REQUEST,
+        FORBIDDEN,
+        METHOD_NOT_ALLOWED,
+        INTERNAL_SERVER_ERROR,
+        UNAUTHORIZED
+    }
+
+    public ErrorResponse(int statusCode, String errorType, String message) {
+        super(statusCode, asSlimeMessage(errorType, message));
+    }
+
+    private static Slime asSlimeMessage(String errorType, String message) {
+        Slime slime = new Slime();
+        Cursor root = slime.setObject();
+        root.setString("error-code", errorType);
+        root.setString("message", message);
+        return slime;
+    }
+
+    public static ErrorResponse notFoundError(String message) {
+        return new ErrorResponse(NOT_FOUND, errorCodes.NOT_FOUND.name(), message);
+    }
+
+    public static ErrorResponse internalServerError(String message) {
+        return new ErrorResponse(INTERNAL_SERVER_ERROR, errorCodes.INTERNAL_SERVER_ERROR.name(), message);
+    }
+
+    public static ErrorResponse badRequest(String message) {
+        return new ErrorResponse(BAD_REQUEST, errorCodes.BAD_REQUEST.name(), message);
+    }
+
+    public static ErrorResponse forbidden(String message) {
+        return new ErrorResponse(FORBIDDEN, errorCodes.FORBIDDEN.name(), message);
+    }
+
+    public static ErrorResponse unauthorized(String message) {
+        return new ErrorResponse(UNAUTHORIZED, errorCodes.UNAUTHORIZED.name(), message);
+    }
+
+    public static ErrorResponse methodNotAllowed(String message) {
+        return new ErrorResponse(METHOD_NOT_ALLOWED, errorCodes.METHOD_NOT_ALLOWED.name(), message);
+    }
+
+}
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/http/flags/FlagDataListResponse.java b/flags/src/main/java/com/yahoo/vespa/flags/http/FlagDataListResponse.java
index b33fc7c2b04..5af97007997 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/http/flags/FlagDataListResponse.java
+++ b/flags/src/main/java/com/yahoo/vespa/flags/http/FlagDataListResponse.java
@@ -1,12 +1,11 @@
 // Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-package com.yahoo.vespa.config.server.http.flags;
+package com.yahoo.vespa.flags.http;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ArrayNode;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 import com.yahoo.container.jdisc.HttpResponse;
 import com.yahoo.jdisc.Response;
-import com.yahoo.vespa.config.server.http.HttpConfigResponse;
 import com.yahoo.vespa.flags.FlagId;
 import com.yahoo.vespa.flags.json.FlagData;
 import com.yahoo.vespa.flags.json.wire.WireFlagDataList;
@@ -54,6 +53,6 @@ public class FlagDataListResponse extends HttpResponse {
 
     @Override
     public String getContentType() {
-        return HttpConfigResponse.JSON_CONTENT_TYPE;
+        return "application/json";
     }
 }
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/http/flags/FlagDataResponse.java b/flags/src/main/java/com/yahoo/vespa/flags/http/FlagDataResponse.java
index 054b218ff2d..f6e81e030c7 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/http/flags/FlagDataResponse.java
+++ b/flags/src/main/java/com/yahoo/vespa/flags/http/FlagDataResponse.java
@@ -1,9 +1,8 @@
 // Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-package com.yahoo.vespa.config.server.http.flags;
+package com.yahoo.vespa.flags.http;
 
 import com.yahoo.container.jdisc.HttpResponse;
 import com.yahoo.jdisc.Response;
-import com.yahoo.vespa.config.server.http.HttpConfigResponse;
 import com.yahoo.vespa.flags.json.FlagData;
 
 import java.io.OutputStream;
@@ -26,6 +25,6 @@ public class FlagDataResponse extends HttpResponse {
 
     @Override
     public String getContentType() {
-        return HttpConfigResponse.JSON_CONTENT_TYPE;
+        return "application/json";
     }
 }
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/http/flags/FlagsHandler.java b/flags/src/main/java/com/yahoo/vespa/flags/http/FlagsHandler.java
index 00f3d457d3d..76f74cbe931 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/http/flags/FlagsHandler.java
+++ b/flags/src/main/java/com/yahoo/vespa/flags/http/FlagsHandler.java
@@ -1,19 +1,17 @@
 // Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-package com.yahoo.vespa.config.server.http.flags;
+package com.yahoo.vespa.flags.http;
 
 import com.google.inject.Inject;
 import com.yahoo.container.jdisc.HttpRequest;
 import com.yahoo.container.jdisc.HttpResponse;
 import com.yahoo.container.jdisc.LoggingRequestHandler;
+import com.yahoo.log.LogLevel;
 import com.yahoo.restapi.Path;
-import com.yahoo.vespa.config.server.http.HttpErrorResponse;
-import com.yahoo.vespa.config.server.http.HttpHandler;
-import com.yahoo.vespa.config.server.http.NotFoundException;
-import com.yahoo.vespa.configserver.flags.FlagsDb;
 import com.yahoo.vespa.flags.FlagDefinition;
 import com.yahoo.vespa.flags.FlagId;
 import com.yahoo.vespa.flags.Flags;
 import com.yahoo.vespa.flags.json.FlagData;
+import com.yahoo.vespa.flags.persistence.FlagsDb;
 import com.yahoo.yolean.Exceptions;
 
 import java.io.UncheckedIOException;
@@ -25,7 +23,8 @@ import java.util.Objects;
  *
  * @author hakonhall
  */
-public class FlagsHandler extends HttpHandler {
+public class FlagsHandler extends LoggingRequestHandler {
+
     private final FlagsDb flagsDb;
 
     @Inject
@@ -35,28 +34,44 @@ public class FlagsHandler extends HttpHandler {
     }
 
     @Override
-    protected HttpResponse handleGET(HttpRequest request) {
+    public HttpResponse handle(HttpRequest request) {
+        try {
+            switch (request.getMethod()) {
+                case GET: return handleGET(request);
+                case DELETE: return handleDELETE(request);
+                case PUT: return handlePUT(request);
+                default: return ErrorResponse.methodNotAllowed("Method '" + request.getMethod() + "' is not supported");
+            }
+        }
+        catch (IllegalArgumentException e) {
+            return ErrorResponse.badRequest(Exceptions.toMessageString(e));
+        }
+        catch (RuntimeException e) {
+            log.log(LogLevel.WARNING, "Unexpected error handling '" + request.getUri() + "'", e);
+            return ErrorResponse.internalServerError(Exceptions.toMessageString(e));
+        }
+    }
+
+    private HttpResponse handleGET(HttpRequest request) {
         Path path = new Path(request.getUri());
         if (path.matches("/flags/v1")) return new V1Response(flagsV1Uri(request), "data", "defined");
         if (path.matches("/flags/v1/data")) return getFlagDataList(request);
         if (path.matches("/flags/v1/data/{flagId}")) return getFlagData(findFlagId(request, path));
         if (path.matches("/flags/v1/defined")) return new DefinedFlags(Flags.getAllFlags());
         if (path.matches("/flags/v1/defined/{flagId}")) return getDefinedFlag(findFlagId(request, path));
-        throw new NotFoundException("Nothing at path '" + path + "'");
+        return ErrorResponse.notFoundError("Nothing at path '" + path + "'");
     }
 
-    @Override
-    protected HttpResponse handlePUT(HttpRequest request) {
+    private HttpResponse handlePUT(HttpRequest request) {
         Path path = new Path(request.getUri());
         if (path.matches("/flags/v1/data/{flagId}")) return putFlagData(request, findFlagId(request, path));
-        throw new NotFoundException("Nothing at path '" + path + "'");
+        return ErrorResponse.notFoundError("Nothing at path '" + path + "'");
     }
 
-    @Override
-    protected HttpResponse handleDELETE(HttpRequest request) {
+    private HttpResponse handleDELETE(HttpRequest request) {
         Path path = new Path(request.getUri());
         if (path.matches("/flags/v1/data/{flagId}")) return deleteFlagData(findFlagId(request, path));
-        throw new NotFoundException("Nothing at path '" + path + "'");
+        return ErrorResponse.notFoundError("Nothing at path '" + path + "'");
     }
 
     private String flagsV1Uri(HttpRequest request) {
@@ -66,9 +81,11 @@ public class FlagsHandler extends HttpHandler {
     }
 
     private HttpResponse getDefinedFlag(FlagId flagId) {
-        FlagDefinition definition = Flags.getFlag(flagId)
-                .orElseThrow(() -> new NotFoundException("Flag " + flagId + " not defined"));
-        return new DefinedFlag(definition);
+        var definedFlag = Flags.getFlag(flagId).map(DefinedFlag::new);
+        if (definedFlag.isPresent()) {
+            return definedFlag.get();
+        }
+        return ErrorResponse.notFoundError("Flag " + flagId + " not defined");
     }
 
     private HttpResponse getFlagDataList(HttpRequest request) {
@@ -77,8 +94,11 @@ public class FlagsHandler extends HttpHandler {
     }
 
     private HttpResponse getFlagData(FlagId flagId) {
-        FlagData data = flagsDb.getValue(flagId).orElseThrow(() -> new NotFoundException("Flag " + flagId + " not set"));
-        return new FlagDataResponse(data);
+        var data = flagsDb.getValue(flagId).map(FlagDataResponse::new);
+        if (data.isPresent()) {
+            return data.get();
+        }
+        return ErrorResponse.notFoundError("Flag " + flagId + " not set");
     }
 
     private HttpResponse putFlagData(HttpRequest request, FlagId flagId) {
@@ -86,7 +106,7 @@ public class FlagsHandler extends HttpHandler {
         try {
             data = FlagData.deserialize(request.getData());
         } catch (UncheckedIOException e) {
-            return HttpErrorResponse.badRequest("Failed to deserialize request data: " + Exceptions.toMessageString(e));
+            return ErrorResponse.badRequest("Failed to deserialize request data: " + Exceptions.toMessageString(e));
         }
 
         if (!isForce(request)) {
@@ -105,16 +125,14 @@ public class FlagsHandler extends HttpHandler {
 
     private FlagId findFlagId(HttpRequest request, Path path) {
         FlagId flagId = new FlagId(path.get("flagId"));
-
-        if (!isForce(request)) {
-            Flags.getFlag(flagId).orElseThrow(() ->
-                    new NotFoundException("There is no flag '" + flagId + "' (use ?force=true to override)"));
+        if (!isForce(request) && Flags.getFlag(flagId).isEmpty()) {
+            throw new IllegalArgumentException("There is no flag '" + flagId + "' (use ?force=true to override)");
         }
-
         return flagId;
     }
 
     private boolean isForce(HttpRequest request) {
         return Objects.equals(request.getProperty("force"), "true");
     }
+
 }
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/http/flags/OKResponse.java b/flags/src/main/java/com/yahoo/vespa/flags/http/OKResponse.java
index 87c02ae56f1..d094e2d5734 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/http/flags/OKResponse.java
+++ b/flags/src/main/java/com/yahoo/vespa/flags/http/OKResponse.java
@@ -1,9 +1,8 @@
 // Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-package com.yahoo.vespa.config.server.http.flags;
+package com.yahoo.vespa.flags.http;
 
 import com.yahoo.container.jdisc.EmptyResponse;
 import com.yahoo.jdisc.Response;
-import com.yahoo.vespa.config.server.http.HttpConfigResponse;
 
 /**
  * @author hakonhall
@@ -15,6 +14,6 @@ public class OKResponse extends EmptyResponse {
 
     @Override
     public String getContentType() {
-        return HttpConfigResponse.JSON_CONTENT_TYPE;
+        return "application/json";
     }
 }
diff --git a/flags/src/main/java/com/yahoo/vespa/flags/http/SlimeJsonResponse.java b/flags/src/main/java/com/yahoo/vespa/flags/http/SlimeJsonResponse.java
new file mode 100644
index 00000000000..dd71795ae43
--- /dev/null
+++ b/flags/src/main/java/com/yahoo/vespa/flags/http/SlimeJsonResponse.java
@@ -0,0 +1,38 @@
+// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.flags.http;
+
+import com.yahoo.container.jdisc.HttpResponse;
+import com.yahoo.slime.JsonFormat;
+import com.yahoo.slime.Slime;
+
+import java.io.IOException;
+import java.io.OutputStream;
+
+/**
+ * A generic Json response using Slime for JSON encoding
+ *
+ * @author bratseth
+ */
+public class SlimeJsonResponse extends HttpResponse {
+
+    private final Slime slime;
+
+    public SlimeJsonResponse(Slime slime) {
+        super(200);
+        this.slime = slime;
+    }
+
+    public SlimeJsonResponse(int statusCode, Slime slime) {
+        super(statusCode);
+        this.slime = slime;
+    }
+
+    @Override
+    public void render(OutputStream stream) throws IOException {
+        new JsonFormat(true).encode(stream, slime);
+    }
+
+    @Override
+    public String getContentType() { return "application/json"; }
+
+}
diff --git a/flags/src/main/java/com/yahoo/vespa/flags/http/V1Response.java b/flags/src/main/java/com/yahoo/vespa/flags/http/V1Response.java
new file mode 100644
index 00000000000..e8ff0bd99a4
--- /dev/null
+++ b/flags/src/main/java/com/yahoo/vespa/flags/http/V1Response.java
@@ -0,0 +1,46 @@
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.flags.http;
+
+import com.yahoo.container.jdisc.HttpResponse;
+import com.yahoo.jdisc.Response;
+import com.yahoo.slime.Cursor;
+import com.yahoo.slime.JsonFormat;
+import com.yahoo.slime.Slime;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.List;
+
+/**
+ * @author hakonhall
+ */
+public class V1Response extends HttpResponse {
+
+    private final Slime slime;
+
+    public V1Response(String flagsV1Uri, String... names) {
+        super(Response.Status.OK);
+        this.slime = generateBody(flagsV1Uri, List.of(names));
+    }
+
+    @Override
+    public void render(OutputStream stream) throws IOException {
+        new JsonFormat(true).encode(stream, slime);
+    }
+
+    @Override
+    public String getContentType() {
+        return "application/json";
+    }
+
+    private static Slime generateBody(String flagsV1Uri, List<String> names) {
+        Slime slime = new Slime();
+        Cursor root = slime.setObject();
+        names.forEach(name -> {
+            Cursor data = root.setObject(name);
+            data.setString("url", flagsV1Uri + "/" + name);
+        });
+        return slime;
+    }
+
+}
diff --git a/configserver-flags/src/main/java/com/yahoo/vespa/configserver/flags/db/FlagsDbImpl.java b/flags/src/main/java/com/yahoo/vespa/flags/persistence/FlagsDb.java
index 5058358ba03..2ed762f2895 100644
--- a/configserver-flags/src/main/java/com/yahoo/vespa/configserver/flags/db/FlagsDbImpl.java
+++ b/flags/src/main/java/com/yahoo/vespa/flags/persistence/FlagsDb.java
@@ -1,9 +1,8 @@
 // Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-package com.yahoo.vespa.configserver.flags.db;
+package com.yahoo.vespa.flags.persistence;
 
 import com.google.inject.Inject;
 import com.yahoo.path.Path;
-import com.yahoo.vespa.configserver.flags.FlagsDb;
 import com.yahoo.vespa.curator.Curator;
 import com.yahoo.vespa.flags.FlagId;
 import com.yahoo.vespa.flags.json.FlagData;
@@ -20,14 +19,15 @@ import java.util.stream.Collectors;
 /**
  * @author hakonhall
  */
-public class FlagsDbImpl implements FlagsDb {
+public class FlagsDb {
+
     private static final Path ROOT_PATH = Path.fromString("/flags/v1");
 
     private final Curator curator;
     private final Curator.DirectoryCache cache;
 
     @Inject
-    public FlagsDbImpl(Curator curator) {
+    public FlagsDb(Curator curator) {
         this.curator = curator;
         curator.create(ROOT_PATH);
         ExecutorService executorService = Executors.newFixedThreadPool(1);
@@ -35,28 +35,28 @@ public class FlagsDbImpl implements FlagsDb {
         cache.start();
     }
 
-    @Override
+    /** Get the String value of the flag. */
     public Optional<FlagData> getValue(FlagId flagId) {
         return Optional.ofNullable(cache.getCurrentData(getZkPathFor(flagId)))
-                .map(ChildData::getData)
-                .map(FlagData::deserializeUtf8Json);
+                       .map(ChildData::getData)
+                       .map(FlagData::deserializeUtf8Json);
     }
 
-    @Override
+    /** Set the String value of the flag. */
     public void setValue(FlagId flagId, FlagData data) {
         curator.set(getZkPathFor(flagId), data.serializeToUtf8Json());
     }
 
-    @Override
+    /** Get all flags that have been set. */
     public Map<FlagId, FlagData> getAllFlags() {
         List<ChildData> dataList = cache.getCurrentData();
         return dataList.stream()
-                .map(ChildData::getData)
-                .map(FlagData::deserializeUtf8Json)
-                .collect(Collectors.toMap(FlagData::id, Function.identity()));
+                       .map(ChildData::getData)
+                       .map(FlagData::deserializeUtf8Json)
+                       .collect(Collectors.toMap(FlagData::id, Function.identity()));
     }
 
-    @Override
+    /** Remove the flag value if it exists. */
     public void removeValue(FlagId flagId) {
         curator.delete(getZkPathFor(flagId));
     }
@@ -64,4 +64,5 @@ public class FlagsDbImpl implements FlagsDb {
     private static Path getZkPathFor(FlagId flagId) {
         return ROOT_PATH.append(flagId.toString());
     }
+
 }
diff --git a/flags/src/main/java/com/yahoo/vespa/flags/persistence/package-info.java b/flags/src/main/java/com/yahoo/vespa/flags/persistence/package-info.java
new file mode 100644
index 00000000000..d4753ed1756
--- /dev/null
+++ b/flags/src/main/java/com/yahoo/vespa/flags/persistence/package-info.java
@@ -0,0 +1,8 @@
+// Copyright 2019 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+/**
+ * @author mpolden
+ */
+@ExportPackage
+package com.yahoo.vespa.flags.persistence;
+
+import com.yahoo.osgi.annotation.ExportPackage;
diff --git a/configserver/src/test/java/com/yahoo/vespa/config/server/http/flags/FlagsHandlerTest.java b/flags/src/test/java/com/yahoo/vespa/flags/http/FlagsHandlerTest.java
index 5ae6ce9820b..8ae1008ba22 100644
--- a/configserver/src/test/java/com/yahoo/vespa/config/server/http/flags/FlagsHandlerTest.java
+++ b/flags/src/test/java/com/yahoo/vespa/flags/http/FlagsHandlerTest.java
@@ -1,25 +1,26 @@
 // Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-package com.yahoo.vespa.config.server.http.flags;
+package com.yahoo.vespa.flags.http;
 
 import com.yahoo.container.jdisc.HttpRequest;
 import com.yahoo.container.jdisc.HttpResponse;
 import com.yahoo.jdisc.http.HttpRequest.Method;
 import com.yahoo.text.Utf8;
-import com.yahoo.vespa.config.server.http.SessionHandlerTest;
-import com.yahoo.vespa.configserver.flags.db.FlagsDbImpl;
 import com.yahoo.vespa.curator.mock.MockCurator;
 import com.yahoo.vespa.flags.FetchVector;
 import com.yahoo.vespa.flags.FlagId;
 import com.yahoo.vespa.flags.Flags;
 import com.yahoo.vespa.flags.UnboundBooleanFlag;
+import com.yahoo.vespa.flags.persistence.FlagsDb;
+import com.yahoo.yolean.Exceptions;
 import org.junit.Test;
 
 import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
 import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
-import static com.yahoo.yolean.Exceptions.uncheck;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.is;
@@ -37,7 +38,7 @@ public class FlagsHandlerTest {
 
     private static final String FLAGS_V1_URL = "https://foo.com:4443/flags/v1";
 
-    private final FlagsDbImpl flagsDb = new FlagsDbImpl(new MockCurator());
+    private final FlagsDb flagsDb = new FlagsDb(new MockCurator());
     private final FlagsHandler handler = new FlagsHandler(FlagsHandler.testOnlyContext(), flagsDb);
 
     @Test
@@ -161,7 +162,7 @@ public class FlagsHandlerTest {
 
     @Test
     public void testForcing() {
-        assertThat(handle(Method.PUT, "/data/" + new FlagId("undef"), "", 404),
+        assertThat(handle(Method.PUT, "/data/" + new FlagId("undef"), "", 400),
                 containsString("There is no flag 'undef'"));
 
         assertThat(handle(Method.PUT, "/data/" + new FlagId("undef") + "?force=true", "", 400),
@@ -191,10 +192,12 @@ public class FlagsHandlerTest {
         HttpResponse response = handler.handle(request);
         assertEquals(expectedStatus, response.getStatus());
         assertEquals("application/json", response.getContentType());
-        return uncheck(() -> SessionHandlerTest.getRenderedString(response));
+        var outputStream = new ByteArrayOutputStream();
+        Exceptions.uncheck(() -> response.render(outputStream));
+        return outputStream.toString(StandardCharsets.UTF_8);
     }
 
     private InputStream makeInputStream(String content) {
         return new ByteArrayInputStream(Utf8.toBytes(content));
     }
-}
\ No newline at end of file
+}
diff --git a/configserver-flags/src/test/java/com/yahoo/vespa/configserver/flags/db/FlagsDbImplTest.java b/flags/src/test/java/com/yahoo/vespa/flags/persistence/FlagsDbTest.java
index ecc9bacb081..5102305af90 100644
--- a/configserver-flags/src/test/java/com/yahoo/vespa/configserver/flags/db/FlagsDbImplTest.java
+++ b/flags/src/test/java/com/yahoo/vespa/flags/persistence/FlagsDbTest.java
@@ -1,5 +1,5 @@
 // Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-package com.yahoo.vespa.configserver.flags.db;
+package com.yahoo.vespa.flags.persistence;
 
 import com.yahoo.vespa.curator.mock.MockCurator;
 import com.yahoo.vespa.flags.FetchVector;
@@ -23,11 +23,11 @@ import static org.junit.Assert.assertTrue;
 /**
  * @author hakonhall
  */
-public class FlagsDbImplTest {
+public class FlagsDbTest {
     @Test
     public void test() {
         MockCurator curator = new MockCurator();
-        FlagsDbImpl db = new FlagsDbImpl(curator);
+        FlagsDb db = new FlagsDb(curator);
 
         Condition condition1 = new Condition(Condition.Type.WHITELIST, FetchVector.Dimension.HOSTNAME, "host1");
         Rule rule1 = new Rule(Optional.of(JsonNodeRawFlag.fromJson("13")), condition1);
@@ -39,8 +39,8 @@ public class FlagsDbImplTest {
         assertTrue(dataCopy.isPresent());
 
         assertEquals("{\"id\":\"id\",\"rules\":[{\"conditions\":[{\"type\":\"whitelist\",\"dimension\":\"hostname\"," +
-                "\"values\":[\"host1\"]}],\"value\":13}],\"attributes\":{\"zone\":\"zone-a\"}}",
-                dataCopy.get().serializeToJson());
+                     "\"values\":[\"host1\"]}],\"value\":13}],\"attributes\":{\"zone\":\"zone-a\"}}",
+                     dataCopy.get().serializeToJson());
 
         FlagId flagId2 = new FlagId("id2");
         FlagData data2 = new FlagData(flagId2, new FetchVector().with(FetchVector.Dimension.ZONE_ID, "zone-a"), rule1);
@@ -53,4 +53,4 @@ public class FlagsDbImplTest {
         db.removeValue(flagId2);
         assertFalse(db.getValue(flagId2).isPresent());
     }
-}
\ No newline at end of file
+}