The Lambda Layer Inspector (L2I)
This CLI tool allows to inspect one or more AWS Lambda layer(s), using the layer ARN(s) as input.
Install
Download the latest binary for Linux (Intel or Arm), macOS, or Windows.
For example, to install l2i from binary on macOS you could do the following:
curl -L https://github.com/mhausenblas/l2i/releases/latest/download/l2i_darwin_amd64.tar.gz \
-o l2i.tar.gz && \
tar xvzf l2i.tar.gz l2i && \
mv l2i /usr/local/bin && \
rm l2i*Use
Once installed, all you need to inspect one or more Lambda layer are their ARNs. For examples of layer ARNs, check out mthenw/awesome-layers.
Plain metadata inspection
If you want to inspect a single AWS Lambda layer, provide the ARN to l2i using
the --layers parameter like so:
$ l2i --layers arn:aws:lambda:eu-west-1:553035198032:layer:git:10
Name: git
Version: 10
Description: Git 2.25.0 and openssh binaries
Created on: 2020-01-13T20:41:57.917+0000
Size: 17,456 kB
Location: https://awslambda-eu-west-1-layers.s3.eu-west-1.amazonaws.com/snapshots/553035198032/git-c86b3b6b-1ff4-48e2-bdc3-3721ae076147?versionId=YhboGnC0BP6h5jlTaS2jUxyeZxXFBQU3
$ l2i --layers arn:aws:lambda:eu-west-1:464622532012:layer:Datadog-Python37:1
Name: Datadog-Python37
Version: 1
Description: Datadog Lambda Layer for Python
Created on: 2019-05-06T18:48:17.694+0000
Size: 7,657 kB
Location: https://awslambda-eu-west-1-layers.s3.eu-west-1.amazonaws.com/snapshots/464622532012/Datadog-Python37-44fdbec2-a76c-4fb4-a3e2-be9781f035be?versionId=4vdBqcXS41OnGhs5Ml16_G31mK2mBaqM
CompatibleRuntimes: python3.7You can also inspect multiple layers at once, using a comma-separated list and
l2i will provide a tabular overview:
$ l2i --layers "arn:aws:lambda:eu-west-1:464622532012:layer:Datadog-Python37:1,arn:aws:lambda:eu-west-1:553035198032:layer:git:10"
NAME VERSION DESCRIPTION CREATED ON SIZE (kB)
Datadog-Python37 1 Datadog Lambda Layer for Python 2019-05-06T18:48:17.694+0000 7,657
git 10 Git 2.25.0 and openssh binaries 2020-01-13T20:41:57.917+0000 17,456Content inspection
If you provide the --export parameter, l2i will not only display metadata of
a layer but also download its contents into the (relative or
absolute) provided path, for example:
$ l2i --layers arn:aws:lambda:eu-west-1:553035198032:layer:git:10 --export .
Name: git
Version: 10
Description: Git 2.25.0 and openssh binaries
Created on: 2020-01-13T20:41:57.917+0000
Size: 17,456 kB
Location: https://awslambda-eu-west-1-layers.s3.eu-west-1.amazonaws.com/snapshots/553035198032/git-c86b3b6b-1ff4-48e2-bdc3-3721ae076147?versionId=YhboGnC0BP6h5jlTaS2jUxyeZxXFBQU3
I exported the layer's contents to: /Users/janedoe/serverless/layer-git-contentIf you now look into the layer-git-content directory you should see something
like this:
$ tree -d layer-git-content/
layer-git-content/
├── bin
├── etc
│  └── ssh
├── lib
│  └── fipscheck
├── libexec
│  ├── git-core
│  │  └── mergetools
│  └── openssh
└── share
├── git-core
│  └── templates
└── licenses
├── fipscheck-1.3.1
├── git-2.25.0
├── openssh-7.4p1
└── pcre2-10.21
17 directories
You can also export multiple layers at once, like so:
$ l2i --layers "arn:aws:lambda:eu-west-1:464622532012:layer:Datadog-Python37:1,arn:aws:lambda:eu-west-1:553035198032:layer:nodejs10:20" --export layers
NAME VERSION DESCRIPTION CREATED ON SIZE (kB)
Datadog-Python37 1 Datadog Lambda Layer for Python 2019-05-06T18:48:17.694+0000 7,657
nodejs10 20 Node.js v10.18.1 custom runtime 2020-01-10T21:32:36.590+0000 12,404
I exported the layers' contents to: /Users/janedoe/serverless/layers/Have fun!
