I was trying to work with AWS Lambda using the awscli on an ubuntu ec2 instance, and I do not have access to the aws console. Note that I am not using serverless or zapper, I directly zip my main.py file along with the dependency files as mentioned here
I run the function like this
aws lambda invoke --function-name python-test --invocation-type RequestResponse outfile.txt
The errors given in the outfile are very vague and dont help in debugging, rather they confuse me more. Using the admin's system, I am able to recognize the errors when I run a test on the console, but How can I check those logs using the awscli ?
So I tried running aws cloudwatch list-metrics > cloudwatch_logs.log
and searching the function name 'python-test' in the cloudwatch_logs.log file, I am able to find Namespace, MetricName, Dimensions for this function, but how do you access the logs ?
Any help with links to similar examples greatly appreciated !
First, get the log group name:
aws logs describe-log-groups --query logGroups[*].logGroupName
[
"/aws/lambda/MyFunction"
]
Then, list the log streams for that log group:
aws logs describe-log-streams --log-group-name '/aws/lambda/MyFunction' --query logStreams[*].logStreamName
[
"2018/02/07/[$LATEST]140c61ffd59442b7b8405dc91d708fdc"
]
Finally, get the log events for that stream:
aws logs get-log-events --log-group-name '/aws/lambda/MyFunction' --log-stream-name '2018/02/07/[$LATEST]140c61ffd59442b7b8405dc91d708fdc'
{
"nextForwardToken": "f/33851760153448034063427449515194237355552440866456338433",
"events": [
{
"ingestionTime": 1517965421523,
"timestamp": 1517965421526,
"message": "START RequestId: bca9c478-0ba2-11e8-81db-4bccfc644168 Version: $LATEST\n"
},
{
"ingestionTime": 1517965424581,
"timestamp": 1517965424567,
"message": "END RequestId: bca9c478-0ba2-11e8-81db-4bccfc644168\n"
},
{
"ingestionTime": 1517965424581,
"timestamp": 1517965424567,
"message": "REPORT RequestId: bca9c478-0ba2-11e8-81db-4bccfc644168\tDuration: 3055.39 ms\tBilled Duration: 3100 ms \tMemory Size: 128 MB\tMax Memory Used: 35 MB\t\n"
}
],
"nextBackwardToken": "b/33851760085631457914695824538087252860391482425578356736"
}
jq flavor:
List AWS lambda group name (if list is too big you might want to filter it with grep):
aws logs describe-log-groups | jq -r ".logGroups[].logGroupName"
Then read message property from latest stream with:
LOG_GROUP_NAME="/aws/lambda/awesomeFunction"
LOG_STREAM_NAME=$(aws logs describe-log-streams --log-group-name "${LOG_GROUP_NAME}" | jq -r '.logStreams | sort_by(.creationTime) | .[-1].logStreamName')
aws logs get-log-events --log-group-name "${LOG_GROUP_NAME}" --log-stream-name "${LOG_STREAM_NAME}" | jq -r '.events[] | select(has("message")) | .message'
You might want to put this in a logs.sh file.
If you want more or other streams you might want to tweak the .logStreams[0] part
Using the AWS CLI can be a bit irritating because the stream name changes as you modify your function. I've found that using awslogs (https://github.com/jorgebastida/awslogs) is a nicer workflow.
List the groups:
awslogs groups
Filter results.
awslogs groups|grep myfunction
Then get the logs from the group.
awslogs get /aws/lambda/ShortenStack-mutationShortenLambdaBC1758AD-6KW0KAD3TYVE
It defaults to the last 5 minutes, but you can add the -s parameter to choose a time, e.g -s 10m for the last 10 minutes.
The output is colourised if you're at the terminal, or plain if you're piping it through other commands, e.g. grep to find something.