YUKI Hiroshi
null+****@clear*****
Fri Feb 28 13:42:25 JST 2014
YUKI Hiroshi 2014-02-28 13:42:25 +0900 (Fri, 28 Feb 2014) New Revision: de51ed257be7fc396e4d99b57434063bc27fdd4f https://github.com/droonga/droonga.org/commit/de51ed257be7fc396e4d99b57434063bc27fdd4f Message: Fix I/O of handlers Modified files: tutorial/plugin-development/handler/index.md Modified: tutorial/plugin-development/handler/index.md (+38 -17) =================================================================== --- tutorial/plugin-development/handler/index.md 2014-02-28 12:55:31 +0900 (b02bbd3) +++ tutorial/plugin-development/handler/index.md 2014-02-28 13:42:25 +0900 (66799c2) @@ -73,7 +73,9 @@ They can be appear in an array, like: "inReplyTo": "(message id)", "statusCode": 200, "type": "countRecords.result", - "body": [10, 10] + "body": { + "counts": [10, 10] + } } ~~~ @@ -159,7 +161,7 @@ module Droonga class Handler < Droonga::Handler def handle(message) - [0] + { "counts" => [0] } end end end @@ -173,7 +175,7 @@ The class `Handler` is a handler class for our new command. * It implements the logic to handle requests. Its instance method `#handle` actually handles requests. -Currently the handler does nothing and returns an array of a number. +Currently the handler does nothing and returns an result including an array of a number. The returned value is used to construct the response body. The handler is bound to the step with the configuration `step.handler`. @@ -221,7 +223,7 @@ Note that you need to specify ./lib directory in RUBYLIB environment variable in # kill $(cat fluentd.pid) # RUBYLIB=./lib fluentd --config fluentd.conf --log fluentd.log --daemon fluentd.pid -Then, send a message for the `countRecords` command to the Droonga Engine. +Then, send a request message for the `countRecords` command to the Droonga Engine. ~~~ # droonga-request --tag starbucks count-records.json @@ -233,7 +235,9 @@ Elapsed time: 0.01494 "inReplyTo": "1392621168.0119512", "statusCode": 200, "type": "countRecords.result", - "body": [0, 0, 0] + "body": { + "counts": [0, 0, 0] + } } ] ~~~ @@ -245,20 +249,20 @@ Look at these points: It is automatically named by the Droonga Engine. * The format of the `body` is same to the returned value of the handler's `handle` method. -There are 3 elements in the array. Why? +There are 3 elements in the array `"counts"`. Why? * Remember that we have configured the `Starbucks` dataset to use 3 partitions (and each has 2 replicas) in the `catalog.json` of [the basic tutorial][basic]. - * Because it is a read-only command, an incoming message is distributed only to paritions, not to replicas. + * Because it is a read-only command, a request is delivered only to paritions, not to replicas. So there are only 3 results, not 6. (TODO: I have to add a figure to indicate active nodes: [000, 001, 010, 011, 020, 021] => [000, 011, 020]) * The `SumCollector` collects them. Those 3 results are joined to just one array by the collector. -As the result, just one array with 3 elements appears in the response message. +As the result, just one array with 3 elements appears in the final response. ### Read-only access to the storage -Now, each instance of the handler class always returns `[0]` as its result. +Now, each instance of the handler class always returns `0` as its result. Let's implement codes to count up the number of records from the actual storage. lib/droonga/plugins/count-records.rb: @@ -267,15 +271,21 @@ lib/droonga/plugins/count-records.rb: (snip) class Handler < Droonga::Handler def handle(message) - table_name = message["body"]["table"] + request = message.request + table_name = request["body"]["table"] table = @context[table_name] count = table.size - [count] + { "counts" => [count] } end end (snip) ~~~ +Look at the argument of the `handle` method. +It is different from the one an adapter receives. +A handler receives a message meaning a distributed task. +So you have to extract the request message from the distributed task by the code `request = message.request`. + The instance variable `@context` is an instance of `Groonga::Context` for the storage of the partition. See the [class reference of Rroonga][Groonga::Context]. You can use any feature of Rroonga via `@context`. @@ -296,7 +306,9 @@ Elapsed time: 0.01494 "inReplyTo": "1392621168.0119512", "statusCode": 200, "type": "countRecords.result", - "body": [12, 12, 11] + "body": { + "counts": [12, 12, 11] + } } ] ~~~ @@ -340,7 +352,9 @@ The response must have a boolean value to indicate "success" or "fail", like: "inReplyTo": "(message id)", "statusCode": 200, "type": "deleteStores.result", - "body": true + "body": { + "success": true + } } ~~~ @@ -425,12 +439,13 @@ module Droonga class Handler < Droonga::Handler def handle(message) - keyword = message["body"]["keyword"] + request = message.request + keyword = request["body"]["keyword"] table = @context["Store"] table.delete do |record| record.key @ keyword end - true + { "success" => true } end end end @@ -438,6 +453,8 @@ module Droonga end ~~~ +Remember, you have to extract the request message from the received task message. + The handler finds and deletes existing records which have the given keyword in its "key", by the [API of Rroonga][Groonga::Table_delete]. And, the `AndCollector` is bound to the step by the configuration `step.collector`. @@ -475,7 +492,9 @@ Elapsed time: 0.01494 "inReplyTo": "1392621168.0119512", "statusCode": 200, "type": "deleteStores.result", - "body": true + "body": { + "success": true + } } ] ~~~ @@ -493,7 +512,9 @@ Elapsed time: 0.01494 "inReplyTo": "1392621168.0119512", "statusCode": 200, "type": "countRecords.result", - "body": [8, 8, 7] + "body": { + "counts": [8, 8, 7] + } } ] ~~~ -------------- next part -------------- HTML����������������������������...Download
