I'm working with a pipeline that pushes JSON entries in batches to my Gcloud Storage bucket. I want to get this data into Kafka.
The way I'm going about it now is using a lambda function that gets triggered every minute to find the files that have changed, open streams from them, read line by line and batch every so often those lines as messages into a kafka producer.
This process is pretty terrible, but it works.... eventually.
I was hoping there'd be a way to do this w/ Kafka Connect or Flink, but there really isn't much development around sensing incremental file additions to a bucket.
Do the JSON entries end up in different files in your bucket? Flink has support for streaming in new files from a source.
Related
I have an ETL application which is suppose to migrate to AWS infra. The scheduler being used in my application is Tivoli Work Scheduler and we want to use the same on cloud as well which has file dependencies.
Now when we move to aws , the files to be watched will land in S3 Bucket. Can we put the OPEN dependency for files in S3? If yes, What would be the hostname ( HOST#Filepath ) ?
If Not, what services should be aligned to serve the purpose. I have both time as well as file dependency in my SCHEDULES.
Eg. The file might get uploaded on S3 at 1AM. AT 3 AM my schedule will get triggered, look for the file in S3 bucket. If present, starts execution and if not then it should wait as per other parameters on tws.
Any help or advice would be nice to have.
If I understand this correctly, job triggered at 3am will identify all files uploaded within last e.g. 24 hours.
You can list all s3 files to list everything uploaded within specific period of time.
Better solution would be to create S3 upload trigger which will send information to SQS and have your code inspect the depth (number of messages) there and start processing the files one by one. An additional benefit would be an assurance that all items are processed without having to worry about time overalpse.
I was wondering if it would be possible to compose Google Storage Objects (specifically csv files) without headers (i.e. without the row with column names) while using gsutil.
Currently, I can do the following:
gsutil compose gs://bucket/test_file_1.csv gs://bucket/test_file_2.csv gs://bucket/test-composition-files.csv
However, I will be unable to ingest test-composition-files.csv into Google BigQuery because compose blindly appended the files (including the column names).
One possible solution would be to download the file locally and process it with pandas, but this is not ideal for large files.
Is there any way to do this via the CLI? I could not find anything in the docs.
By reading the comment, I think you are spending effort in the wrong way. I understood that you wanted to load your files into big query, but the large number of file prevented you to do this (too many API calls). And dataflow is too slow.
Maybe you can think differently. I have 2 solutions to propose
If you need "near real time" ingestion, and if file size is bellow 1.5Gb, the best way is to build a function which read the file and perform a stream write to BigQuery. This function is triggered by a Cloud Storage event. If there is several file in the same time, several functions will be spawn. Be careful, stream write to BigQuery is not free
If you can wait up to 2 minutes when a file arrive, I recommend you to build a Cloud Functions, triggered every 2 minutes. This function read the file name in a bucket, move them to a sub directory and perform a load job of all the files in the sub directory. You are limited to 1000 load jobs per day (and per table), a day contains 1440 minutes. Batch every 2 minutes you are OK. The load job are free.
Is it acceptable alternatives?
I'm writing a Spark Streaming application where the input data is put into an S3 bucket in small batches (using Database Migration Service - DMS). The Spark application is the only consumer. I'm considering two possible architectures:
Have Spark Streaming watch an S3 prefix and pick up new objects as they
come in
Stream data from S3 to a Kinesis stream (through a Lambda function triggered as new S3 objects are created by DMS) and use the stream as input for the Spark application.
While the second solution will work, the first solution is simpler. But are there any pitfalls? Looking at this guide, I'm concerned about two specific points:
The more files under a directory, the longer it will take to scan for changes — even if no files have been modified.
We will be keeping the S3 data indefinitely. So the number of objects under the prefix being monitored is going to increase very quickly.
“Full” Filesystems such as HDFS tend to set the modification time on their files as soon as the output stream is created. When a file is opened, even before data has been completely written, it may be included in the DStream - after which updates to the file within the same window will be ignored. That is: changes may be missed, and data omitted from the stream.
I'm not sure if this applies to S3, since to my understanding objects are created atomically and cannot be updated afterwards as is the case with ordinary files.
I posted this to Spark mailing list and got a good answer from Steve Loughran.
Theres a slightly-more-optimised streaming source for cloud streams
here
https://github.com/hortonworks-spark/cloud-integration/blob/master/spark-cloud-integration/src/main/scala/org/apache/spark/streaming/hortonworks/CloudInputDStream.scala
Even so, the cost of scanning S3 is one LIST request per 5000 objects;
I'll leave it to you to work out how many there will be in your
application —and how much it will cost. And of course, the more LIST
calls tehre are, the longer things take, the bigger your window needs
to be.
“Full” Filesystems such as HDFS tend to set the modification time on their files as soon as the output stream is created. When a file is
opened, even before data has been completely written, it may be
included in the DStream - after which updates to the file within the
same window will be ignored. That is: changes may be missed, and data
omitted from the stream.
Objects written to S3 are't visible until the upload completes, in an
atomic operation. You can write in place and not worry.
The timestamp on S3 artifacts comes from the PUT tim. On multipart
uploads of many MB/many GB uploads, thats when the first post to
initiate the MPU is kicked off. So if the upload starts in time window
t1 and completed in window t2, the object won't be visible until t2,
but the timestamp will be of t1. Bear that in mind.
The lambda callback probably does have better scalability and
resilience; not tried it myself.
Since the number of objects in my scenario is going to be much larger than 5000 and will continue to grow very quickly, S3 to Spark doesn't seem to be a feasible option. I did consider moving/renaming processed objects in Spark Streaming, but the Spark Streaming application code seems to only receive DStreams and no information about which S3 object the data is coming from. So I'm going to go with the Lambda and Kinesis option.
I have a large number of logfiles from a service that I need to regularly run analysis on via EMR/Hive. There are thousands of new files per day, and they can technically come out of order relative to the file name (e.g. a batch of files comes a week after the date in the file name).
I did an initial load of the files via Snowball, then set up a script that syncs the entire directory tree once per day using the 'aws s3 sync' cli command. This is good enough for now, but I will need a more realtime solution in the near future. The issue with this approach is that it takes a very long time, on the order of 30 minutes per day. And using a ton of bandwidth all at once! I assume this is because it needs to scan the entire directory tree to determine what files are new, then sends them all at once.
A realtime solution would be beneficial in 2 ways. One, I can get the analysis I need without waiting up to a day. Two, the network use would be lower and more spread out, instead of spiking once a day.
It's clear that 'aws s3 sync' isn't the right tool here. Has anyone dealt with a similar situation?
One potential solution could be:
Set up a service on the log-file side that continuously syncs (or aws s3 cp) new files based on the modified date. But wouldn't that need to scan the whole directory tree on the log server as well?
For reference, the log-file directory structure is like:
/var/log/files/done/{year}/{month}/{day}/{source}-{hour}.txt
There is also a /var/log/files/processing/ directory for files being written to.
Any advice would be appreciated. Thanks!
You could have a Lambda function triggered automatically as a new object is saved on your S3 bucket. Check Using AWS Lambda with Amazon S3 for details. The event passed to the Lambda function will contain the file name, allowing you to target only the new files in the syncing process.
If you'd like wait until you have, say 1,000 files, in order to sync in batch, you could use AWS SQS and the following workflow (using 2 Lambda functions, 1 CloudWatch rule and 1 SQS queue):
S3 invokes Lambda whenever there's a new file to sync
Lambda stores the filename in SQS
CloudWatch triggers another Lambda function every X minutes/hours to check how many files are there in SQS for syncing. Once there's 1,000 or more, it retrieves those filenames and run the syncing process.
Keep in mind that Lambda has a hard timeout of 5 minutes. If you sync job takes too long, you'll need to break it in smaller chunks.
You could set the bucket up to log HTTP requests to a separate bucket, then parse the log to look for newly created files and their paths. One troublespot, as well as PUT requests, you have to look for the multipart upload ops which are a sequence of POSTs. Best to log for a few days to see what gets created before putting any effort in to this approach
Considering the fact that there is no data pipeline available in Singapore region, are there any alternatives available to efficiently push csv data to dynamodb?
If it was me, I would setup an s3 event notification on a bucket that fires a lambda function each time a CSV file was dropped into it.
The Notification would let Lambda know that a new file was available and a lambda function would be responsible for loading the data into dynamodb.
This would work better (because of the limits of lambda) if the CSV files were not huge, so they could be processed in a reasonable amount of time, and the bonus is the only worked that would need to be done once it was working would be to simply drop the new files into the right bucket - no server required.
Here is a github repository that has a CSV->Dynamodb loader written in java - it might help get you started.