nsq-to-gs

nsq-to-gs

Stream an NSQ channel to Google Cloud Storage

Based on nsq-to-s3 by chrusty

Written (more like adjusted) by Eran Sandler (@erans) http://eran.sandler.co.il

Parameters

• topic: The NSQ topic to subscribe to
• channel: An NSQ channel name to use (defaults to an automatically-generated ephemeral channel)
• max-in-flight: The maximum number of unFinished messages to allow (effectively a flush-batch size)
• max-in-flight-time: The maximum number of seconds to wait before flushing (in case maxInFlight is not enough)
• lookupd-http-address: The address of an NSQLookup daemon to connect to
• nsqd-tcp-address: A specific NSQ daemon to connect to
• bucket-seconds: The time-bucket-size of each file you want to end up with on GS, if we don't hit bucketMessages first (eg 3600 will give you one file on GS per-hour)
• bucket-messages: Total number of messages to bucket (if bucketSeconds doesn't elapse first)
• gsbucket: The GS bucket to store the files on (eg "nsq-archive")
• gspath: A path to store the archive files under (eg "/live-dumps")
• gsfileprefix: The generate file name prefix (eg "mylogfile" which would be mylogfile-20151117_1003.json.gz)
• batchmode: Which mode to run in [memory, disk, channel]
• bufferfile: The name of a file to use as a local on-disk buffer between flushes to GS (should be something durable)
• extension: Extension for files on GS (default is json)

Modes (current)

NSQ-to-GS can operate in several different modes, depending on your storage and/or durability requirements:

"Batch-on-disk"

• Subs to NSQ
• De-dupes in memory (map[string][bool] where string is a hash of the message payload)
• Once max-in-flight is reached it flushes messages to disk then Finish()es them
• After timeBucket has elapsed it stops consuming, sticks the file on GS, clears the de-dupe map and continues
• You would be well-advised to use some kind of persistent storage

"In-memory"

As with batch-on-disk but all messages are kept in-memory between flushes to GS. If you stop the process then you will lose messages!

Modes (planned)

"Abandoned-channel"

• Subs to NSQ (creates a channel)
• Waits for timeBucket to elapse
• Pauses the channel
• Takes all the messages off the queue, de-dupes in memory, sticks them on GS
• Finish()es the messages
• Unpauses the channel
• Repeat

"Continuous-sync-to-gs"

• As with batch-on-disk but syncs to GS every x seconds
• Either overwrites the same file on GS, or piles up new ones
• At the end of the time-bucket the interim files are removed from GS

Examples

Consuming a topic, buffering on disk, flushing in-flight at 1000 messages, flushing to GS every 5 minutes:

nsq-to-gs -gsproject=myproject -gsbucket=nsq-archive -topic=firehose -channel='nsq-to-gs#ephemeral' -lookupd-http-address=10.0.0.2:4161 -gspath=/live-dumps/firehose -bucket-seconds=300 -max-in-flight=1000 -batchmode=disk

Bugs (current)

• Dupes can still occur around flush boundaries
• The timer for flushing to GS is based on events arriving (not on absolute time). This means that he filenames/numbers will creep (just being pedantic)
• Should optionally compress files for GS