pkuwm commented on a change in pull request #761: Add REST read endpoints to helix-rest for metadata store directory URL: https://github.com/apache/helix/pull/761#discussion_r381053697
########## File path: helix-rest/src/main/java/org/apache/helix/rest/server/resources/metadatastore/MetadataStoreDirectoryAccessor.java ########## @@ -111,41 +132,56 @@ public Response deleteMetadataStoreRealm(@PathParam("realm") String realm) { } /** - * Gets sharding keys mapped at path "HTTP GET /sharding-keys" which returns all sharding keys in - * a namespace, or path "HTTP GET /sharding-keys?realm={realmName}" which returns sharding keys in - * a realm. + * Gets all sharding keys mapped at paths: + * - "HTTP GET /sharding-keys" which returns all sharding keys in a namespace. + * - "HTTP GET /sharding-keys?realm={realm}" which returns sharding keys in the realm. + * - "HTTP GET /sharding-keys?prefix={prefix}" which returns sharding keys that have the prefix. + * -- JSON response example for this path: + * { + * "prefix": "/sharding/key", + * "shardingKeys": [{ + * "realm": "testRealm2", + * "shardingKey": "/sharding/key/1/f" + * }, { + * "realm": "testRealm2", + * "shardingKey": "/sharding/key/1/e" + * }, { + * "realm": "testRealm1", + * "shardingKey": "/sharding/key/1/b" + * }, { + * "realm": "testRealm1", + * "shardingKey": "/sharding/key/1/a" + * }] + * } + * + * - "HTTP GET /sharding-keys?realm={realm}&prefix={prefix}" which returns sharding keys in the + * realm and that have the prefix. * - * @param realm Query param in endpoint path - * @return Json representation of a map: shardingKeys -> collection of sharding keys. + * @param realm Query param in endpoint path: metadata store realm. + * @param prefix Query param in endpoint path: prefix substring of sharding key. + * @return Json representation for the sharding keys. */ @GET @Path("/sharding-keys") - public Response getShardingKeys(@QueryParam("realm") String realm) { - Map<String, Object> responseMap; - Collection<String> shardingKeys; + public Response getShardingKeys(@QueryParam("realm") String realm, + @QueryParam("prefix") String prefix) { try { - // If realm is not set in query param, the endpoint is: "/sharding-keys" - // to get all sharding keys in a namespace. - if (realm == null) { - shardingKeys = _metadataStoreDirectory.getAllShardingKeys(_namespace); - // To avoid allocating unnecessary resource, limit the map's capacity only for - // SHARDING_KEYS. - responseMap = new HashMap<>(1); + if (realm == null && prefix == null) { + // For endpoint: "/sharding-keys" to get all sharding keys in a namespace. + return getAllShardingKeys(); + } else if (prefix == null) { + // For endpoint: "/sharding-keys?realm={realm}" + return getAllShardingKeysInRealm(realm); + } else if (realm == null) { + // For endpoint: "/sharding-keys?prefix={prefix}" + return getAllShardingKeysUnderPath(prefix); } else { - // For endpoint: "/sharding-keys?realm={realmName}" - shardingKeys = _metadataStoreDirectory.getAllShardingKeysInRealm(_namespace, realm); - // To avoid allocating unnecessary resource, limit the map's capacity only for - // SHARDING_KEYS and SINGLE_METADATA_STORE_REALM. - responseMap = new HashMap<>(2); - responseMap.put(MetadataStoreRoutingConstants.SINGLE_METADATA_STORE_REALM, realm); + // For endpoint: "/sharding-keys?realm={realm}&prefix={prefix}" + return getRealmShardingKeysUnderPath(realm, prefix); Review comment: > There is a good way to simplify the logic here utilizing the default values as @dasahcc has mentioned. If the prefix is not provided, consider assigning "/" to the prefix variable and use the same logic as the situation where prefix exists. @NealSun96 I don't think adding "/" to the prefix var is a better idea because: - The Json responses are different for each case here. If you assign "/" to a method, the response could have `{ "prefix": "/" }` - I've tried to find a good default value for this prefix. If I assign "/" as a default value, I've no idea how to differentiate if prefix is not provide or it is "/". - The code logic to generate response map is different. If I don't understand your idea, feel free to clarify it. Thanks for the tip. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@helix.apache.org For additional commands, e-mail: reviews-h...@helix.apache.org