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This is more a question rather than an issue.

I am trying to collect logs from an OpenFaaS python flask function, and hope I can retain them as log files on disk, which will rotate once a day. During this process, I find that:

  1. I don't really know how to overwrite the log provider to save logs to a file on the disk of a k8s master node. The only related tutorial I see is the static logger provider written in Golang. I hope can get some tutorials in python.
  2. I cannot get logs by faas-cli logs <func_name>, I can only see logs by docker logs <container_name>. How could I see logs by faas-cli?

A further Question No.3 is that, if collecting logs to a file system is unrealistic, do I need to make sure my logs can be shown by faas-cli logs <func_name> before trying to collect it by Elastic Search or Grafana Loki like here? I am not familiar with these two things.

Additionally, I am considering to move some of my business from python to c++ for performance improvement. I want to use a pistachio server behind of-watchdog, so my Question No.4 is, should I use a log library, or just stdout logs, in my c++ pistachio application.

Hope someone could give me an example on how to implement the log collection for python flask server and c++ pistachio server in OpenFaaS.

Here is the reproduce process of faas-cli logs not showing any logs.

Environment

  • Windows 10 64-bit
  • Docker Desktop 4.3.0 with kind
  • docker version 20.10.11
  • k8s version v1.22.4
  • FaaS-netes with tag 0.16.4
  • FaaS-CLI version 0.14.2

Steps to Reproduce

Create a function by template. I am using the flask template with of-watchdog.

faas-cli new --lang python3-http flask-faas --prefix lyudmilalala

Overwrite the handler.py in the flask-faas folder.

from flask import current_app
import sys
import logging

logger = logging.getLogger(__name__)
logger.setLevel("INFO")

logger.info("global logger info")
logger.error("global logger error")
print("global print") # cannot print
sys.stdout.write("global stdout\n")
sys.stderr.write("global stderr\n")

def handle(event, context):
    current_app.logger.info("app logger: " + repr(event.query)) # cannot print
    logger.info("logger info: " + repr(event.query))
    logger.error("logger error: " + repr(event.query))
    print("print: " + repr(event.query)) # cannot print
    sys.stdout.write("stdout: " + repr(event.query) + "\n")
    sys.stderr.write("stderr: " + repr(event.query) + "\n")

    inner(event)
    return {
        "statusCode": 200,
        "body": "Welcom to flask-demo v1.0!"
    }

def inner(event):
    current_app.logger.info("inner app logger: " + repr(event.query)) # cannot print
    logger.info("inner logger info: " + repr(event.query))
    logger.error("inner logger error: " + repr(event.query))
    print("inner print: " + repr(event.query)) # cannot print
    sys.stdout.write("inner stdout: " + repr(event.query) + "\n")
    sys.stderr.write("inner stderr: " + repr(event.query)  + "\n")

Overwrite the flask-faas.yml

192.168.1.124 is my local IP.

version: 1.0
provider:
  name: openfaas
  gateway: http://192.168.1.124:31112
functions:
  flask-faas:
    lang: python3-http
    handler: ./flask-faas
    image: lyudmilalala/flask-faas:1.0
    environment:
      write_debug: true 
      PYTHONUNBUFFERED: 1

Start the function.

faas-cil up -f flask-faas.yml

Call the function with curl.

curl --request GET 'http://192.168.1.124:31112/function/flask-faas?filepath=data/10ibt_H.msgpack&filterStr=00000*****'

Expected Behaviour

Some logs show when running faas-cli logs flask-faas or kubectl logs XXX

Current Behaviour

Run faas-cli logs flask-faas shows nothing

Run kubectl logs flask-faas-57f6449bbd-z5cld -n openfaas-fn shows an error. I am not sure if it is related with openfaas or not.

Error from server: Get "https://192.168.65.4:10250/containerLogs/openfaas-fn/flask-faas-57f6449bbd-z5cld/flask-faas": open /run/config/pki/apiserver-kubelet-client.crt: no such file or directory

Only when using docker logs the logger and stdout/stderr works (2ef3e197a8b1 is the id of the function container).

2023/03/16 12:40:09 Version: 0.9.10     SHA: eefeb9dd8c979398a46fc0decc3297591362bfab
2023/03/16 12:40:09 Forking: python, arguments: [index.py]
2023/03/16 12:40:09 Started logging: stderr from function.
2023/03/16 12:40:09 Started logging: stdout from function.
2023/03/16 12:40:09 Watchdog mode: http fprocess: "python index.py"
2023/03/16 12:40:09 Timeouts: read: 10s write: 10s hard: 10s health: 10s     
2023/03/16 12:40:09 Listening on port: 8080
2023/03/16 12:40:09 Writing lock-file to: /tmp/.lock
2023/03/16 12:40:09 Metrics listening on port: 8081
2023/03/16 12:40:09 stdout: global print
2023/03/16 12:40:09 stdout: global stdout
2023/03/16 12:40:09 stderr: global logger error
2023/03/16 12:40:09 stderr: global stderr
2023/03/16 12:43:37 stderr: INFO:function.handler:logger info: ImmutableMultiDict([('filepath', 'data/10ibt_H.msgpack'), ('filterStr', '00000*****')])    
2023/03/16 12:43:37 stderr: ERROR:function.handler:logger error: ImmutableMultiDict([('filepath', 'data/10ibt_H.msgpack'), ('filterStr', '00000*****')])  
2023/03/16 12:43:37 stderr: stderr: ImmutableMultiDict([('filepath', 'data/10ibt_H.msgpack'), ('filterStr', '00000*****')])
2023/03/16 12:43:37 stdout: print: ImmutableMultiDict([('filepath', 'data/10ibt_H.msgpack'), ('filterStr', '00000*****')])
2023/03/16 12:43:37 stdout: stdout: ImmutableMultiDict([('filepath', 'data/10ibt_H.msgpack'), ('filterStr', '00000*****')])
2023/03/16 12:43:37 stdout: inner print: ImmutableMultiDict([('filepath', 'data/10ibt_H.msgpack'), ('filterStr', '00000*****')])
2023/03/16 12:43:37 stdout: inner stdout: ImmutableMultiDict([('filepath', 'data/10ibt_H.msgpack'), ('filterStr', '00000*****')])
2023/03/16 12:43:37 stderr: INFO:function.handler:inner logger info: ImmutableMultiDict([('filepath', 'data/10ibt_H.msgpack'), ('filterStr', '00000*****')])
2023/03/16 12:43:37 stderr: ERROR:function.handler:inner logger error: ImmutableMultiDict([('filepath', 'data/10ibt_H.msgpack'), ('filterStr', '00000*****')])
2023/03/16 12:43:37 stderr: inner stderr: ImmutableMultiDict([('filepath', 'data/10ibt_H.msgpack'), ('filterStr', '00000*****')])
2023/03/16 12:43:37 GET /?filepath=data/10ibt_H.msgpack&filterStr=00000%2A%2A%2A%2A%2A - 200 OK - ContentLength: 189B (0.0023s)
Lyudmila Sun
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0 Answers0