chore(lambda-layer-awscli): add update mechanism for AWS CLI

We bundle the AWS CLI. This adds a mechanism to keep up with new updates
of the CLI. It adds a script that should be executed periodically to
create a PR with a version update.

We had to install and bump to Python v3 because newer versions of the
AWS CLI have ended support for Python 2.7.

packages/@aws-cdk/lambda-layer-awscli/awscli.version

@@ -0,0 +1 @@
+1.22.46

packages/@aws-cdk/lambda-layer-awscli/build-tools/bump-awscli-version.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+set -eu
+scriptdir=$(cd $(dirname $0) && pwd)
+
+package=awscli
+tmpfile=_pip.json
+
+curl -LsSf https://pypi.org/pypi/awscli/json > $tmpfile
+trap "rm $tmpfile" EXIT
+version=$(node -p "require('./${tmpfile}').info.version")
+
+if [[ $version != 1.* ]]; then
+    echo "Expected version 1.*, got ${version}" >&2
+    exit 1
+fi
+
+echo "AWS CLI is currently at ${version}"
+
+echo $version > $scriptdir/../awscli.version

packages/@aws-cdk/lambda-layer-awscli/layer/Dockerfile

@@ -1,12 +1,5 @@
 FROM public.ecr.aws/lambda/provided:latest
 
-#
-# versions
-#
-
-# This is the last version that still supports Python 2.7
-ARG AWSCLI_VERSION=1.19.112
-
 USER root
 RUN mkdir -p /opt
 WORKDIR /tmp
@@ -16,21 +9,24 @@ WORKDIR /tmp
 #
 
 RUN yum update -y \
-    && yum install -y zip unzip wget tar gzip
+    && yum install -y zip unzip wget tar gzip python3
 
 #
 # aws cli
 #
 
+ARG AWSCLI_VERSION=0.0.0
+
 RUN curl https://s3.amazonaws.com/aws-cli/awscli-bundle-${AWSCLI_VERSION}.zip -o awscli-bundle.zip
 RUN unzip awscli-bundle.zip
-RUN ./awscli-bundle/install -i /opt/awscli -b /opt/awscli/aws
+RUN python3 ./awscli-bundle/install -i /opt/awscli -b /opt/awscli/aws
 
 # organize for self-contained usage
-RUN mv /opt/awscli                                    /opt/awscli.tmp
-RUN mv /opt/awscli.tmp/lib/python2.7/site-packages    /opt/awscli
-RUN mv /opt/awscli.tmp/bin                            /opt/awscli/bin
-RUN mv /opt/awscli/bin/aws                            /opt/awscli
+RUN mv /opt/awscli                                      /opt/awscli.tmp
+RUN pyver=$(python3 -c 'import sys; v = sys.version_info; print(f"{v[0]}.{v[1]}")') && \
+    mv /opt/awscli.tmp/lib/python${pyver}/site-packages /opt/awscli
+RUN mv /opt/awscli.tmp/bin                              /opt/awscli/bin
+RUN mv /opt/awscli/bin/aws                              /opt/awscli
 
 # cleanup
 RUN rm -fr /opt/awscli.tmp
@@ -39,6 +35,13 @@ RUN rm -rf \
     /opt/awscli/setuptools* \
     /opt/awscli/awscli/examples
 
+#
+# Test that the CLI works
+#
+
+RUN yum install -y groff
+RUN /opt/awscli/aws help
+
 #
 # create the bundle
 #
@@ -49,4 +52,4 @@ RUN cd /opt \
     && ls -alh /layer.zip;
 
 WORKDIR /
-ENTRYPOINT [ "/bin/bash" ]
+ENTRYPOINT [ "/bin/bash" ]

packages/@aws-cdk/lambda-layer-awscli/layer/build.sh

@@ -3,11 +3,13 @@ set -euo pipefail
 
 cd $(dirname $0)
 
-echo ">> Building AWS Lambda layer inside a docker image..."
+version=$(cat ../awscli.version)
+
+echo ">> Building AWS Lambda layer inside a docker image for CLI version ${version}..."
 
 TAG='aws-lambda-layer'
 
-docker build -t ${TAG} .
+docker build -t ${TAG} . --build-arg AWSCLI_VERSION=${version}
 
 echo ">> Extrating layer.zip from the build container..."
 CONTAINER=$(docker run -d ${TAG} false)