slow local invoke compared to direct lambda invocation

[peteruhnak]

I'm running into a strange slowdown when locally invoking a lambda function.

Step pulling the docker image always takes around 30 seconds. There's barely any network traffic, so it is not actually downloading it. Maybe a timeout, or it is always computing the checksum? (The same slowdown is present when I do docker pull lambci/lambda

$ time sam local invoke HelloWorld -e event.json
2018/03/29 12:55:26 Successfully parsed template.yaml
�[34mINFO�[0m[0000] Unable to use system certificate pool: crypto/x509: system root pool is not available on Windows
2018/03/29 12:55:26 Connected to Docker 1.37
�[34mINFO�[0m[0000] Unable to use system certificate pool: crypto/x509: system root pool is not available on Windows
2018/03/29 12:55:26 Fetching lambci/lambda:nodejs6.10 image for nodejs6.10 runtime...
nodejs6.10: Pulling from lambci/lambda
Digest: sha256:bc47c223a2accf47c51adc6e1949bda9b557764be38a76ebac73e545044079cc
Status: Image is up to date for lambci/lambda:nodejs6.10
2018/03/29 12:55:58 Invoking index.handler (nodejs6.10)
2018/03/29 12:55:58 Mounting /d/prog/sam-node-hello-world as /var/task:ro inside runtime container
�[32mSTART RequestId: 9556341d-a069-139c-cef9-eb19b1ea1c41 Version: $LATEST�[0m
�[34m2018-03-29T10:56:00.433Z   9556341d-a069-139c-cef9-eb19b1ea1c41    �[0mLOG: Name is Bob
�[32mEND RequestId: 9556341d-a069-139c-cef9-eb19b1ea1c41�[0m
�[32mREPORT RequestId: 9556341d-a069-139c-cef9-eb19b1ea1c41     Duration: 6.09 ms       Billed Duration: 100 ms Memory Size: 128 MB     Max Memory Used: 28 MB  �[0m

"Hello Bob"

real    0m33.644s
user    0m0.000s
sys     0m0.000s

I would expect performance similar to invoking it directly.

$ time docker run -v "$PWD":/var/task lambci/lambda index.handler '{"name" : "Bob"}'
START RequestId: d14605bd-2f8e-1aad-0b06-ea972b2ff0a3 Version: $LATEST
2018-03-29T11:08:29.563Z        d14605bd-2f8e-1aad-0b06-ea972b2ff0a3    LOG: Name is Bob
END RequestId: d14605bd-2f8e-1aad-0b06-ea972b2ff0a3
REPORT RequestId: d14605bd-2f8e-1aad-0b06-ea972b2ff0a3  Duration: 6.03 ms       Billed Duration: 100 ms Memory Size: 1536 MB    Max Memory Used: 23 MB

"Hello Bob"

real    0m0.883s
user    0m0.015s
sys     0m0.000s

[n3ziniuka5]

If you experience the same slowdown by just doing docker pull lambci/lambda then something is wrong with docker, not sam-local. You should look or ask for a solution elsewhere.

In the meantime, you can try sam local invoke --skip-pull-image=true HelloWorld -e event.json

[jfuss]

This seems to be answered by @n3ziniuka5. Closing