[
https://issues.apache.org/jira/browse/STORM-138?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14002445#comment-14002445
]
ASF GitHub Bot commented on STORM-138:
--------------------------------------
Github user d2r commented on a diff in the pull request:
https://github.com/apache/incubator-storm/pull/84#discussion_r12817824
--- Diff: storm-core/src/jvm/backtype/storm/spout/ShellSpout.java ---
@@ -35,91 +35,84 @@
private SpoutOutputCollector _collector;
private String[] _command;
private ShellProcess _process;
+ private SpoutMsg spoutMsg;
public ShellSpout(ShellComponent component) {
this(component.get_execution_command(), component.get_script());
}
-
+
public ShellSpout(String... command) {
_command = command;
}
-
+
public void open(Map stormConf, TopologyContext context,
SpoutOutputCollector collector) {
- _process = new ShellProcess(_command);
_collector = collector;
- try {
- Number subpid = _process.launch(stormConf, context);
- LOG.info("Launched subprocess with pid " + subpid);
- } catch (IOException e) {
- throw new RuntimeException("Error when launching multilang
subprocess\n" + _process.getErrorsString(), e);
- }
+ _process = new ShellProcess(_command);
+
+ Number subpid = _process.launch(stormConf, context);
+ LOG.info("Launched subprocess with pid " + subpid);
}
public void close() {
_process.destroy();
}
- private JSONObject _next;
public void nextTuple() {
- if (_next == null) {
- _next = new JSONObject();
- _next.put("command", "next");
+ if (spoutMsg == null) {
+ spoutMsg = new SpoutMsg();
}
-
- querySubprocess(_next);
+ spoutMsg.setCommand("next");
+ spoutMsg.setId("");
+ querySubprocess();
}
- private JSONObject _ack;
public void ack(Object msgId) {
- if (_ack == null) {
- _ack = new JSONObject();
- _ack.put("command", "ack");
+ if (spoutMsg == null) {
+ spoutMsg = new SpoutMsg();
}
-
- _ack.put("id", msgId);
- querySubprocess(_ack);
+ spoutMsg.setCommand("ack");
+ spoutMsg.setId(msgId);
+ querySubprocess();
}
- private JSONObject _fail;
public void fail(Object msgId) {
- if (_fail == null) {
- _fail = new JSONObject();
- _fail.put("command", "fail");
+ if (spoutMsg == null) {
+ spoutMsg = new SpoutMsg();
}
-
- _fail.put("id", msgId);
- querySubprocess(_fail);
+ spoutMsg.setCommand("fail");
+ spoutMsg.setId(msgId);
+ querySubprocess();
}
- private void querySubprocess(Object query) {
+ private void querySubprocess() {
try {
- _process.writeMessage(query);
+ _process.writeSpoutMsg(spoutMsg);
while (true) {
- JSONObject action = _process.readMessage();
- String command = (String) action.get("command");
+ ShellMsg shellMsg = _process.readShellMsg();
+ String command = shellMsg.getCommand();
if (command.equals("sync")) {
return;
} else if (command.equals("log")) {
- String msg = (String) action.get("msg");
+ String msg = shellMsg.getMsg();
LOG.info("Shell msg: " + msg);
} else if (command.equals("emit")) {
- String stream = (String) action.get("stream");
- if (stream == null) stream = Utils.DEFAULT_STREAM_ID;
--- End diff --
This is not a big enough issue to keep from merging this in. If we run
into troubles with this down the road, we can file another JIRA as an
enhancement.
> Pluggable serialization for multilang
> -------------------------------------
>
> Key: STORM-138
> URL: https://issues.apache.org/jira/browse/STORM-138
> Project: Apache Storm (Incubating)
> Issue Type: New Feature
> Reporter: James Xu
> Priority: Minor
>
> https://github.com/nathanmarz/storm/issues/373
> Currently JSON is used to serialize tuples for multilang. It would be great
> if the serialization mechanism were pluggable so that using richer types with
> multilang would be possible.
> ---------
> francis-liberty: Hello, I am a newbie here, and I wanted to pick up this
> issue. I also noticed a recent PR here #697 by jsgilmore, is it feasible for
> this issue, too?
> I looked around the source code, and I would like to talk about my opinions
> on this issue here.
> For now, ShellProcess only supports JSON to communicate with multilang
> process: read, write. And, ShellSpout and ShellBolt talk with ShellProcess
> through JSON, too. This is all because ShellProcess's interface use
> JSONObject only. Conceptually, ShellProcess should encapsulate the multilang
> details, and talk with Bolt and Spout using Tuple. (jsgilmore invented two
> new classes, Immission and Emission. But I think all information Bolt and
> Spout need is in Tuple already, no need for new data structures.) So, I think
> it would be much cleaner to do serialization in ShellProcess only, and both
> ShellSpout and ShellBolt don't know anything about how ShellProcess convert
> between Tuple and strings.
> So, I suppose I can do the work of
> 1. change the interface of ShellProcess to return and accept Tuple data
> structure, instead of JSONObject.
> 2. make ShellSpout and ShellBolt work on Tuple, all information like task_id,
> stream_id and tuples should be retrieve/encapsulate in this data structure.
> 3. what other serialization format would you like to add? I think in the end
> we need to add some example other than JSON to storm-starter storm.py/rb,
> which I would also like to work on.
> ----------
> jsgilmore: Hi, all serialisation is done in the JSONSerialiser, so no
> serialisation is done in ShellBolt, ShellProcess or ShellSpout. They just
> send around the Emission and Immission classes. The point of the ISerializer
> interface is to achieve the separation of serialisation.
> I come from the multilang side of Storm, so I'm not that familiar with the
> internal Storm structures. If there is a class that the ISerializer interface
> can use, instead of the Emission and Immission classes, I'm open to it.
> I would recommend that further discussion of PR #697 rather happen in the PR
> thread itself though.
> I created an issue to add protocol buffer serialisation for multilang to
> Storm in issue #654 , but I didn't see this issue. The whole purpose of PR
> #697 is to solve this issue.
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