Exception thrown when Lambda is not initialized in begin_subsegment

[chanchiem]

When Lambda is not initialized in begin_subsegment(), an exception is thrown because the global SDK config module was improperly named.

[ShehryarKh]

@chanchiem
Hi, I am still seeing this bug when running locally.

running a flask application
/init.py

from aws_xray_sdk.core import xray_recorder

xray_recorder.configure(
    sampling=False,
    context_missing='LOG_ERROR',
    daemon_address='x-ray-daemon:2000'
)

/app.py

from bla import xray_recorder

xray_recorder.capture('form')
def form():
    do something

/docker-compose.yml

services:
  x-ray-daemon:
    image: amazon/aws-xray-daemon
    ports:
      - "2000:2000/udp"
    networks:
      - zapi
    volumes:
      - ~/.aws/:/root/.aws/:ro
    environment:
      - AWS_REGION=us-east-1

/Pipfile

aws-xray-sdk = "~=2.3.0"

response when I call my api locally

segment form discarded due to Lambda worker still initializing

the full application is inside of docker. When I rundocker-compose up
I see x-ray-daemon_1 | 2019-02-14T20:41:50Z [Info] Initializing AWS X-Ray daemon 3.0.0

any idea?

[chanchiem]

Hey, this issue is different from the issue that you're experiencing. This issue is specific to an exception thrown as a result of the misnamed global configuration.

It looks like the issue you're having could be happening due to two things:

1. Running Flask on Lambda is not yet supported. The solution you have is to log the FacadeSegmentException, and this can cause potential errors if your middleware attempts to begin a segment.
2. The container did not yet finish initializing, so the underlying facade segment has not been generated yet.

Some follow up questions:

• Are you running this docker inside Lambda?
• Is this happening every time you run your code or is it probabilistic?
• When you are calling your API locally, are you running it on your local machine or running it on a tool like AWS SAM to run Lambda locally?

[ShehryarKh]

Hey, yes I'm running the API locally on my machine. It is occurring every time. Also not I am not running the docker inside lambda. If I push up my code, I can see the traces/segments working, just unable to test it locally.

[chanchiem]

So are you running it locally through a tool like AWS SAM or your local machine?

If completely local, it confuses me why you would see this log error because this only happens if your recorder is using the Lambda Context.

Are you explicitly setting the context somewhere to use the Lambda Context?
Something like:

from aws_xray_sdk.core import xray_recorder, lambda_launcher

xray_recorder.configure(
  context=lambda_launcher.LambdaContext()
)

# or the following
xray_recorder.context = lambda_launcher.LambdaContext()

[ShehryarKh]

no, I am not. It's completely local. If I follow the steps of Running the X-Ray Daemon in a Docker Container, the following occurs

aws-xray-daemon-macos-3.x ./xray_mac -o -n us-east-1
2019-02-14T12:39:22-05:00 [Info] Initializing AWS X-Ray daemon 3.0.0
2019-02-14T12:39:22-05:00 [Info] Using buffer memory limit of 100 MB
2019-02-14T12:39:22-05:00 [Info] 1600 segment buffers allocated
2019-02-14T12:39:22-05:00 [Info] Using region: us-east-1
2019-02-14T12:39:22-05:00 [Info] Starting proxy http server on 127.0.0.1:2000

It seems to just stay at Starting proxy http server on 127.0.0.1:2000

can that be part of the issue?

[chanchiem]

Hmm it shouldn't be the issue because the SDK doesn't actually get information back from the Daemon. It sends the trace information through UDP, so it's sort of send it and forget it.

Can you try explicitly setting the context on your local build with a configuration that explicitly uses the default Context and report to me the results?

from aws_xray_sdk.core import xray_recorder
from aws_xray_sdk.core.context import Context

xray_recorder.configure(
# Add your other configuration information as well
  context=Context()
)

[ShehryarKh]

okay do I did this:
/init.py

from aws_xray_sdk.core import xray_recorder
from aws_xray_sdk.core.context import Context

xray_recorder.configure(
    sampling=False,
    context_missing='LOG_ERROR',
    daemon_address='x-ray-daemon:2000',
    context=Context()
)

/app.py

from bla import xray_recorder

@xray_recorder.capture('form_submit')
def form_submit()
    do something

this is returning

cannot find the current segment/subsegment, please make sure you have a segment open
| No segment found, cannot begin subsegment form_submit.