fix: use python3 or python2 for alpine

In alpine3.12, they removed the python package in favor of either
python2 or python3.
https://wiki.alpinelinux.org/wiki/Release_Notes_for_Alpine_3.12.0#python2_no_longer_provides_python_and_python-devel

However, nodejs 12, 10 require python2 for building from source. I added
a change in update.sh that swaps out python3 for python2 in those older
versions for alpine Dockerfiles.

Refs #1330

10/alpine3.10/Dockerfile

@@ -33,7 +33,7 @@ RUN addgroup -g 1000 node \
         libgcc \
         linux-headers \
         make \
-        python \
+        python2 \
     # gpg keys listed at https://github.com/nodejs/node#release-keys
     && for key in \
       4ED778F539E3634C779C87C6D7062848A1AB005C \

10/alpine3.11/Dockerfile

@@ -33,7 +33,7 @@ RUN addgroup -g 1000 node \
         libgcc \
         linux-headers \
         make \
-        python \
+        python2 \
     # gpg keys listed at https://github.com/nodejs/node#release-keys
     && for key in \
       4ED778F539E3634C779C87C6D7062848A1AB005C \

10/alpine3.9/Dockerfile

@@ -33,7 +33,7 @@ RUN addgroup -g 1000 node \
         libgcc \
         linux-headers \
         make \
-        python \
+        python2 \
     # gpg keys listed at https://github.com/nodejs/node#release-keys
     && for key in \
       4ED778F539E3634C779C87C6D7062848A1AB005C \

12/alpine3.10/Dockerfile

@@ -33,7 +33,7 @@ RUN addgroup -g 1000 node \
         libgcc \
         linux-headers \
         make \
-        python \
+        python2 \
     # gpg keys listed at https://github.com/nodejs/node#release-keys
     && for key in \
       4ED778F539E3634C779C87C6D7062848A1AB005C \

12/alpine3.11/Dockerfile

@@ -33,7 +33,7 @@ RUN addgroup -g 1000 node \
         libgcc \
         linux-headers \
         make \
-        python \
+        python2 \
     # gpg keys listed at https://github.com/nodejs/node#release-keys
     && for key in \
       4ED778F539E3634C779C87C6D7062848A1AB005C \

12/alpine3.12/Dockerfile

@@ -33,7 +33,7 @@ RUN addgroup -g 1000 node \
         libgcc \
         linux-headers \
         make \
-        python \
+        python2 \
     # gpg keys listed at https://github.com/nodejs/node#release-keys
     && for key in \
       4ED778F539E3634C779C87C6D7062848A1AB005C \

12/alpine3.9/Dockerfile

@@ -33,7 +33,7 @@ RUN addgroup -g 1000 node \
         libgcc \
         linux-headers \
         make \
-        python \
+        python2 \
     # gpg keys listed at https://github.com/nodejs/node#release-keys
     && for key in \
       4ED778F539E3634C779C87C6D7062848A1AB005C \

14/alpine3.10/Dockerfile

@@ -33,7 +33,7 @@ RUN addgroup -g 1000 node \
         libgcc \
         linux-headers \
         make \
-        python \
+        python3 \
     # gpg keys listed at https://github.com/nodejs/node#release-keys
     && for key in \
       4ED778F539E3634C779C87C6D7062848A1AB005C \

14/alpine3.11/Dockerfile

@@ -33,7 +33,7 @@ RUN addgroup -g 1000 node \
         libgcc \
         linux-headers \
         make \
-        python \
+        python3 \
     # gpg keys listed at https://github.com/nodejs/node#release-keys
     && for key in \
       4ED778F539E3634C779C87C6D7062848A1AB005C \

14/alpine3.12/Dockerfile

@@ -33,7 +33,7 @@ RUN addgroup -g 1000 node \
         libgcc \
         linux-headers \
         make \
-        python \
+        python3 \
     # gpg keys listed at https://github.com/nodejs/node#release-keys
     && for key in \
       4ED778F539E3634C779C87C6D7062848A1AB005C \

Dockerfile-alpine.template

@@ -33,7 +33,7 @@ RUN addgroup -g 1000 node \
         libgcc \
         linux-headers \
         make \
-        python \
+        ${PYTHON_VERSION} \
     # gpg keys listed at https://github.com/nodejs/node#release-keys
     && for key in \
       "${NODE_KEYS[@]}"

update.sh

@@ -167,6 +167,15 @@ function update_node_version() {
       )\""
       sed -Ei -e "s/(alpine:)0.0/\\1${alpine_version}/" "${dockerfile}-tmp"
       sed -Ei -e "s/CHECKSUM=CHECKSUM_x64/CHECKSUM=${checksum}/" "${dockerfile}-tmp"
+
+      # Use python2 for nodejs < 14 on alpine
+      if [ "$version" -lt 14 ]; then
+        pythonVersion="python2"
+      else
+        pythonVersion="python3"
+      fi
+
+      sed -Ei -e 's/\$\{PYTHON_VERSION\}/'"${pythonVersion}"'/' "${dockerfile}-tmp"
     elif is_debian "${variant}"; then
       sed -Ei -e "s/(buildpack-deps:)name/\\1${variant}/" "${dockerfile}-tmp"
     elif is_debian_slim "${variant}"; then