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_r381000691
##########
File path:
helix-rest/src/main/java/org/apache/helix/rest/server/resources/metadatastore/MetadataStoreDirectoryAccessor.java
##########
@@ -111,41 +135,74 @@ 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"
+ * }]
+ * }
*
- * @param realm Query param in endpoint path
- * @return Json representation of a map: shardingKeys -> collection of
sharding keys.
+ * - "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: 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);
}
} catch (NoSuchElementException ex) {
return notFound(ex.getMessage());
}
+ }
- responseMap.put(MetadataStoreRoutingConstants.SHARDING_KEYS, shardingKeys);
-
- return JSONRepresentation(responseMap);
+ /**
+ * Gets all path-based sharding keys for a queried realm at endpoint:
+ * "GET /metadata-store-realms/{realm}/sharding-keys". This endpoint is
equivalent to
+ * the endpoint: "GET /sharding-keys?realm={realm}".
+ *
+ * @param realm Queried metadata store realm to get sharding keys.
+ * @return All path-based sharding keys in the queried realm.
+ */
+ @GET
+ @Path("/metadata-store-realms/{realm}/sharding-keys")
+ public Response getRealmShardingKeys(@PathParam("realm") String realm) {
+ try {
+ return getAllShardingKeysInRealm(realm);
+ } catch (NoSuchElementException ex) {
+ return notFound(ex.getMessage());
Review comment:
@NealSun96 Thanks for reviewing.
As you referred in the link, `400 Bad Request`: The request could not be
understood by the server due to **malformed syntax**. If you request a POST/PUT
with json payload which has syntax error, I believe `Bad Request` is more
suitable.
`404 Not Found` means the endpoint is correct but resource is not found in
server, which matches exactly our case here `NoSuchElementException`. (refs as
an examples:
- https://stackoverflow.com/questions/26968479/404-not-found-or-bad-request;
-
https://stackoverflow.com/questions/19671317/400-bad-request-http-error-code-meaning)
What do you think?
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