Ok so I’ve been having a problem with logging for a while now. I use a centralized logging platform (Seq) to try and aggregate the logs of the containers I run but most of the log messages come through as errors. This is because the containers would stream their output to stderr and even though it’s formatted it comes as one big error message.
Example:
[2025-01-06 18:17:23] INFO Registering with TVA backend, encode Job status: available
That’s all one big error message I receive even though it’s an INFO message. And every container is different. Their error message is formatted differently, some goes to stdout instead of stderr, some actually work.
Is there a piece of software that I can run that will intercept these messages and convert them to GELF?
Thanks
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Loving this thing.
Oh this looks promising.
Seq is expecting structured logs which yours aren’t. So you want to either convert your app’s logs into a structured format (which is generally hard for a random third-party application) or use a log collector that’s fine with non-structured logs (e.g. Loki+grafana don’t care about the shape is your logs and you can format the output while querying).
For live monitoring (not offline!), maybe dozzle can help?
I’m not sure about your exact ask, I’d probably head towards setting up logstash and elasticsearch. It might be overkill for your needs though.
I’m not clear in the post I guess so I’ll try to be more clear here.
- I’m using Seq for my centralized logging.
- The logs I get from most of my containers are not in GELF format. I cannot change that unless I change how logging works in all the programs I use. So I’ll need to edit every source code and compile or ask each project to update their logging and output to GELF.
- They are all shown as errors or info. It depends on the container because some send their logging info to stderr and some to stdout.
- I’m looking for something that can intercept those logs from my other containers, format them to GELF, and send the formatted logs to Seq.
No I get what you’re asking for I’m just mentioning that sometimes it’s easier to use an application that can read multiple formats than it is to try to finagle everything back into one format.
Yeah but the thing is I have it set up to read the logs being sent out from my Docker containers. Even though I’ve set the containers to output using the GELF driver they don’t really do that. The log messages my container send are not in GELF format so I have to find a way to fix that.
Best of luck with it, logging’s always a severe pain in the ass.
Generally no, there is no one piece of software that can magically handle the quirks of each other piece of software. If there is, someone is making a lot of money by selling it.
If you want to handle your uncommon output formats, you’ll need to define them in your log processor.
Well I can get the logs in Seq. I don’t know how to process the logs that come in so they are at the right level, timestamp, message, etc. Guess I look into it tomorrow…
https://docs.datalust.co/docs/collecting-docker-container-logs
You have a formatting issue. Solve for that instead of just switching to something else hoping it will get better.
I’ve done that. I don’t have a formatting issue. The containers I’m trying to get logs from have a formatting issue. They don’t stream their logs in GELF. I am getting the logs but I can’t change the formatting that they send me unless I mess with the code itself.
