[BucketingSink] notify on moving into pending/ final state

[Rinat]

Hi mates, I got a proposal about functionality of BucketingSink.

During implementation of one of our tasks we got the following need - create a meta-file, with the path and additional information about the file, created by BucketingSink, when it’s been moved into final place.

Unfortunately such behaviour is currently not available for us. 

We’ve implemented our own Sink, that provides an opportunity to register notifiers, that will be called, when file state is changing, but current API doesn’t allow us to add such behaviour using inheritance ...

It seems, that such functionality could be useful, and could be a part of BucketingSink API

What do you sink, should I make a PR ?

Sincerely yours,

Rinat Sharipov

Software Engineer at 1DMP CORE Team

email: [hidden email]

mobile: [phone]

CleverDATA

make your data clever

[Piotr Nowojski]

Hi,

I see that could be a useful feature. What exactly now is preventing you from inheriting from BucketingSink? Maybe it would be just enough to make the BucketingSink easier extendable.

One thing now that could collide with such feature is that Kostas is now working on larger BucketingSink rework/refactor. 

Piotrek

On 8 Jun 2018, at 16:38, Rinat <[hidden email]> wrote:

Hi mates, I got a proposal about functionality of BucketingSink.

During implementation of one of our tasks we got the following need - create a meta-file, with the path and additional information about the file, created by BucketingSink, when it’s been moved into final place.

Unfortunately such behaviour is currently not available for us. 

We’ve implemented our own Sink, that provides an opportunity to register notifiers, that will be called, when file state is changing, but current API doesn’t allow us to add such behaviour using inheritance ...

It seems, that such functionality could be useful, and could be a part of BucketingSink API

What do you sink, should I make a PR ?

Sincerely yours,

Rinat Sharipov

Software Engineer at 1DMP CORE Team

email: [hidden email]

mobile: [phone]

CleverDATA

make your data clever

[Rinat]

Hi guys, thx for your reply.

The following code info is actual for release-1.5.0 tag, org.apache.flink.streaming.connectors.fs.bucketing.BucketingSink class

For now, BucketingSink has the following lifecycle of files

When moving files from opened to pending state:

1. on each item (method invoke:434 line), we check that suitable bucket exist, and contain opened file, in case, when opened file doesn’t exist, we create one, and write item to it
2. on each item (method invoke:434 line), we check that suitable opened file doesn’t exceed the limits, and if limits are exceeded, we close it and move into pending state using closeCurrentPartFile:568 line - private method
3. on each timer request (onProcessingTime:482 line), we check, if items haven't been added to the opened file longer, than specified period of time, we close it, using the same private method closeCurrentPartFile:588 line

So, the only way, that we have, is to call our hook from closeCurrentPartFile, that is private, so we copy-pasted the current impl and injected our logic there

Files are moving from pending state into final, during checkpointing lifecycle, in notifyCheckpointComplete:657 line, that is public, and contains a lot of logic, including discovery of files in pending states, synchronization of state access and it’s modification, etc … 

So we couldn’t override it, or call super method and add some logic, because when current impl changes the state of files, it removes them from state, and we don’t have any opportunity to know, 

for which files state have been changed.

To solve such problem, we've created the following interface

/**
 * The {@code FileStateChangeCallback} is used to perform any additional operations, when {@link BucketingSink}
 * moves file from one state to another. For more information about state management of {@code BucketingSink}, look
 * through it's official documentation.
 */
public interface FileStateChangeCallback extends Serializable {

    /**
     * Used to perform any additional operations, related with moving of file into next state.
     *
     * @param fs provides access for working with file system
     * @param path path to the file, moved into next state
     *
     * @throws IOException if something went wrong, while performing any operations with file system
     */
    void call(FileSystem fs, Path path) throws IOException;
}

And have added an ability to register this callbacks in BucketingSink impl in the following manner

public BucketingSink<T> registerOnFinalStateChangeCallback(FileStateChangeCallback… callbacks) {...}

public BucketingSink<T> registerOnPendingStateChangeCallback(FileStateChangeCallback... callbacks) {...}

I’m ready to discuss the best ways, how such hooks could be implemented in the core impl or any other improvements, that will help us to add such functionality into our extension, using public api, instead of copy-pasting the source code.

Thx for your help, mates =)

On 11 Jun 2018, at 11:37, Piotr Nowojski <[hidden email]> wrote:

Hi,

I see that could be a useful feature. What exactly now is preventing you from inheriting from BucketingSink? Maybe it would be just enough to make the BucketingSink easier extendable.

One thing now that could collide with such feature is that Kostas is now working on larger BucketingSink rework/refactor. 

Piotrek

On 8 Jun 2018, at 16:38, Rinat <[hidden email]> wrote:

Hi mates, I got a proposal about functionality of BucketingSink.

During implementation of one of our tasks we got the following need - create a meta-file, with the path and additional information about the file, created by BucketingSink, when it’s been moved into final place.

Unfortunately such behaviour is currently not available for us. 

We’ve implemented our own Sink, that provides an opportunity to register notifiers, that will be called, when file state is changing, but current API doesn’t allow us to add such behaviour using inheritance ...

It seems, that such functionality could be useful, and could be a part of BucketingSink API

What do you sink, should I make a PR ?

Sincerely yours,

Rinat Sharipov

Software Engineer at 1DMP CORE Team

email: [hidden email]

mobile: [phone]

CleverDATA

make your data clever

Sincerely yours,

Rinat Sharipov

Software Engineer at 1DMP CORE Team

email: [hidden email]

mobile: [phone]

CleverDATA

make your data clever

[Piotr Nowojski]

Hi,

Couple of things:

1. Please create a Jira ticket with this proposal, so we can move discussion from user mailing list.

I haven’t thought it through, so take my comments with a grain of salt, however:

2. If we were to go with such callback, I would prefer to have one BucketStateChangeCallback, with methods like `onInProgressToPending(…)`, `onPendingToFinal`, `onPendingToCancelled(…)`, etc, in oppose to having one interface passed three times/four times for different purposes.

3. Other thing that I had in mind is that BucketingSink could be rewritten to extend TwoPhaseCommitSinkFunction. In that case, with 

public class BucketingSink2 extends TwoPhaseCommitSinkFunction<???>

user could add his own hooks by overriding following methods

BucketingSink2#beginTransaction, BucketingSink2#preCommit, BucketingSink2#commit, BucketingSink2#abort. For example:

public class MyBucketingSink extends BucketingSink2 {

  @Override

  protected void  commit(??? txn) {

    super.commit(txn);

    // My hook on moving file from pending to commit state

  };

}

Alternatively, we could implement before mentioned callbacks support in TwoPhaseCommitSinkFunction and provide such feature to Kafka/Pravega/BucketingSink at once.

Piotrek

On 13 Jun 2018, at 22:45, Rinat <[hidden email]> wrote:

Hi guys, thx for your reply.

The following code info is actual for release-1.5.0 tag, org.apache.flink.streaming.connectors.fs.bucketing.BucketingSink class

For now, BucketingSink has the following lifecycle of files

When moving files from opened to pending state:

1. on each item (method invoke:434 line), we check that suitable bucket exist, and contain opened file, in case, when opened file doesn’t exist, we create one, and write item to it
2. on each item (method invoke:434 line), we check that suitable opened file doesn’t exceed the limits, and if limits are exceeded, we close it and move into pending state using closeCurrentPartFile:568 line - private method
3. on each timer request (onProcessingTime:482 line), we check, if items haven't been added to the opened file longer, than specified period of time, we close it, using the same private method closeCurrentPartFile:588 line

So, the only way, that we have, is to call our hook from closeCurrentPartFile, that is private, so we copy-pasted the current impl and injected our logic there

Files are moving from pending state into final, during checkpointing lifecycle, in notifyCheckpointComplete:657 line, that is public, and contains a lot of logic, including discovery of files in pending states, synchronization of state access and it’s modification, etc … 

So we couldn’t override it, or call super method and add some logic, because when current impl changes the state of files, it removes them from state, and we don’t have any opportunity to know, 

for which files state have been changed.

To solve such problem, we've created the following interface

/**
 * The {@code FileStateChangeCallback} is used to perform any additional operations, when {@link BucketingSink}
 * moves file from one state to another. For more information about state management of {@code BucketingSink}, look
 * through it's official documentation.
 */
public interface FileStateChangeCallback extends Serializable {

    /**
     * Used to perform any additional operations, related with moving of file into next state.
     *
     * @param fs provides access for working with file system
     * @param path path to the file, moved into next state
     *
     * @throws IOException if something went wrong, while performing any operations with file system
     */
    void call(FileSystem fs, Path path) throws IOException;
}

And have added an ability to register this callbacks in BucketingSink impl in the following manner

public BucketingSink<T> registerOnFinalStateChangeCallback(FileStateChangeCallback… callbacks) {...}

public BucketingSink<T> registerOnPendingStateChangeCallback(FileStateChangeCallback... callbacks) {...}

I’m ready to discuss the best ways, how such hooks could be implemented in the core impl or any other improvements, that will help us to add such functionality into our extension, using public api, instead of copy-pasting the source code.

Thx for your help, mates =)

On 11 Jun 2018, at 11:37, Piotr Nowojski <[hidden email]> wrote:

Hi,

I see that could be a useful feature. What exactly now is preventing you from inheriting from BucketingSink? Maybe it would be just enough to make the BucketingSink easier extendable.

One thing now that could collide with such feature is that Kostas is now working on larger BucketingSink rework/refactor. 

Piotrek

On 8 Jun 2018, at 16:38, Rinat <[hidden email]> wrote:

Hi mates, I got a proposal about functionality of BucketingSink.

During implementation of one of our tasks we got the following need - create a meta-file, with the path and additional information about the file, created by BucketingSink, when it’s been moved into final place.

Unfortunately such behaviour is currently not available for us. 

We’ve implemented our own Sink, that provides an opportunity to register notifiers, that will be called, when file state is changing, but current API doesn’t allow us to add such behaviour using inheritance ...

It seems, that such functionality could be useful, and could be a part of BucketingSink API

What do you sink, should I make a PR ?

Sincerely yours,

Rinat Sharipov

Software Engineer at 1DMP CORE Team

email: [hidden email]

mobile: [phone]

CleverDATA

make your data clever

Sincerely yours,

Rinat Sharipov

Software Engineer at 1DMP CORE Team

email: [hidden email]

mobile: [phone]

CleverDATA

make your data clever

[Rinat]

Hi Piotr, I’ve create an issue https://issues.apache.org/jira/browse/FLINK-9592

The third proposal looks great, may I try to contribute this issue ?

On 14 Jun 2018, at 12:29, Piotr Nowojski <[hidden email]> wrote:

Hi,

Couple of things:

1. Please create a Jira ticket with this proposal, so we can move discussion from user mailing list.

I haven’t thought it through, so take my comments with a grain of salt, however:

2. If we were to go with such callback, I would prefer to have one BucketStateChangeCallback, with methods like `onInProgressToPending(…)`, `onPendingToFinal`, `onPendingToCancelled(…)`, etc, in oppose to having one interface passed three times/four times for different purposes.

3. Other thing that I had in mind is that BucketingSink could be rewritten to extend TwoPhaseCommitSinkFunction. In that case, with 

public class BucketingSink2 extends TwoPhaseCommitSinkFunction<???>

user could add his own hooks by overriding following methods

BucketingSink2#beginTransaction, BucketingSink2#preCommit, BucketingSink2#commit, BucketingSink2#abort. For example:

public class MyBucketingSink extends BucketingSink2 {

  @Override

  protected void  commit(??? txn) {

    super.commit(txn);

    // My hook on moving file from pending to commit state

  };

}

Alternatively, we could implement before mentioned callbacks support in TwoPhaseCommitSinkFunction and provide such feature to Kafka/Pravega/BucketingSink at once.

Piotrek

Sincerely yours,

Rinat Sharipov

Software Engineer at 1DMP CORE Team

email: [hidden email]

mobile: [phone]

CleverDATA

make your data clever

[Rinat]

Hi Piotr, during the migration to the latest Flink version, we’ve decided to try to contribute this functionality to the master branch.

PR is available here https://github.com/apache/flink/pull/6824 

More details about hooking the state changes in BucketingSink are available in https://issues.apache.org/jira/browse/FLINK-9592 

Thx !

On 14 Jun 2018, at 23:29, Rinat <[hidden email]> wrote:

Hi Piotr, I’ve create an issue https://issues.apache.org/jira/browse/FLINK-9592

The third proposal looks great, may I try to contribute this issue ?

On 14 Jun 2018, at 12:29, Piotr Nowojski <[hidden email]> wrote:

Hi,

Couple of things:

1. Please create a Jira ticket with this proposal, so we can move discussion from user mailing list.

I haven’t thought it through, so take my comments with a grain of salt, however:

2. If we were to go with such callback, I would prefer to have one BucketStateChangeCallback, with methods like `onInProgressToPending(…)`, `onPendingToFinal`, `onPendingToCancelled(…)`, etc, in oppose to having one interface passed three times/four times for different purposes.

3. Other thing that I had in mind is that BucketingSink could be rewritten to extend TwoPhaseCommitSinkFunction. In that case, with 

public class BucketingSink2 extends TwoPhaseCommitSinkFunction<???>

user could add his own hooks by overriding following methods

BucketingSink2#beginTransaction, BucketingSink2#preCommit, BucketingSink2#commit, BucketingSink2#abort. For example:

public class MyBucketingSink extends BucketingSink2 {

  @Override

  protected void  commit(??? txn) {

    super.commit(txn);

    // My hook on moving file from pending to commit state

  };

}

Alternatively, we could implement before mentioned callbacks support in TwoPhaseCommitSinkFunction and provide such feature to Kafka/Pravega/BucketingSink at once.

Piotrek

Sincerely yours,

Rinat Sharipov

Software Engineer at 1DMP CORE Team

email: [hidden email]

mobile: [phone]

CleverDATA

make your data clever

Sincerely yours,

Rinat Sharipov

Software Engineer at 1DMP CORE Team

email: [hidden email]

mobile: [phone]

CleverDATA

make your data clever

[Dawid Wysakowicz-2]

Hi Ribat, 

I haven't checked your PR but we introduced a new connector in flink 1.6 called StreamingFileSink that is supposed to replace BucketingSink long term. I think it might solve a few problems of yours. Have you checked it by chance?

Best,

Dawid

On Thu, 11 Oct 2018, 14:10 Rinat, <[hidden email]> wrote:

Hi Piotr, during the migration to the latest Flink version, we’ve decided to try to contribute this functionality to the master branch.

PR is available here https://github.com/apache/flink/pull/6824 

More details about hooking the state changes in BucketingSink are available in https://issues.apache.org/jira/browse/FLINK-9592 

Thx !

On 14 Jun 2018, at 23:29, Rinat <[hidden email]> wrote:

Hi Piotr, I’ve create an issue https://issues.apache.org/jira/browse/FLINK-9592

The third proposal looks great, may I try to contribute this issue ?

On 14 Jun 2018, at 12:29, Piotr Nowojski <[hidden email]> wrote:

Hi,

Couple of things:

1. Please create a Jira ticket with this proposal, so we can move discussion from user mailing list.

I haven’t thought it through, so take my comments with a grain of salt, however:

2. If we were to go with such callback, I would prefer to have one BucketStateChangeCallback, with methods like `onInProgressToPending(…)`, `onPendingToFinal`, `onPendingToCancelled(…)`, etc, in oppose to having one interface passed three times/four times for different purposes.

3. Other thing that I had in mind is that BucketingSink could be rewritten to extend TwoPhaseCommitSinkFunction. In that case, with 

public class BucketingSink2 extends TwoPhaseCommitSinkFunction<???>

user could add his own hooks by overriding following methods

BucketingSink2#beginTransaction, BucketingSink2#preCommit, BucketingSink2#commit, BucketingSink2#abort. For example:

public class MyBucketingSink extends BucketingSink2 {

  @Override

  protected void  commit(??? txn) {

    super.commit(txn);

    // My hook on moving file from pending to commit state

  };

}

Alternatively, we could implement before mentioned callbacks support in TwoPhaseCommitSinkFunction and provide such feature to Kafka/Pravega/BucketingSink at once.

Piotrek

Sincerely yours,

Rinat Sharipov

Software Engineer at 1DMP CORE Team

email: [hidden email]

mobile: [phone]

CleverDATA

make your data clever

Sincerely yours,

Rinat Sharipov

Software Engineer at 1DMP CORE Team

email: [hidden email]

mobile: [phone]

CleverDATA

make your data clever

[Kostas Kloudas]

Hi Rinat,

I have commented on your PR and on the JIRA.

Let me know what you think.

Cheers,

Kostas

On Oct 11, 2018, at 4:45 PM, Dawid Wysakowicz <[hidden email]> wrote:

Hi Ribat, 

I haven't checked your PR but we introduced a new connector in flink 1.6 called StreamingFileSink that is supposed to replace BucketingSink long term. I think it might solve a few problems of yours. Have you checked it by chance?

Best,

Dawid

On Thu, 11 Oct 2018, 14:10 Rinat, <[hidden email]> wrote:

Hi Piotr, during the migration to the latest Flink version, we’ve decided to try to contribute this functionality to the master branch.

PR is available here https://github.com/apache/flink/pull/6824 

More details about hooking the state changes in BucketingSink are available in https://issues.apache.org/jira/browse/FLINK-9592 

Thx !

On 14 Jun 2018, at 23:29, Rinat <[hidden email]> wrote:

Hi Piotr, I’ve create an issue https://issues.apache.org/jira/browse/FLINK-9592

The third proposal looks great, may I try to contribute this issue ?

On 14 Jun 2018, at 12:29, Piotr Nowojski <[hidden email]> wrote:

Hi,

Couple of things:

1. Please create a Jira ticket with this proposal, so we can move discussion from user mailing list.

I haven’t thought it through, so take my comments with a grain of salt, however:

2. If we were to go with such callback, I would prefer to have one BucketStateChangeCallback, with methods like `onInProgressToPending(…)`, `onPendingToFinal`, `onPendingToCancelled(…)`, etc, in oppose to having one interface passed three times/four times for different purposes.

3. Other thing that I had in mind is that BucketingSink could be rewritten to extend TwoPhaseCommitSinkFunction. In that case, with 

public class BucketingSink2 extends TwoPhaseCommitSinkFunction<???>

user could add his own hooks by overriding following methods

BucketingSink2#beginTransaction, BucketingSink2#preCommit, BucketingSink2#commit, BucketingSink2#abort. For example:

public class MyBucketingSink extends BucketingSink2 {

  @Override

  protected void  commit(??? txn) {

    super.commit(txn);

    // My hook on moving file from pending to commit state

  };

}

Alternatively, we could implement before mentioned callbacks support in TwoPhaseCommitSinkFunction and provide such feature to Kafka/Pravega/BucketingSink at once.

Piotrek

Sincerely yours,

Rinat Sharipov

Software Engineer at 1DMP CORE Team

email: [hidden email]

mobile: [phone]

CleverDATA

make your data clever

Sincerely yours,

Rinat Sharipov

Software Engineer at 1DMP CORE Team

email: [hidden email]

mobile: [phone]

CleverDATA

make your data clever