Permit installing Python packages from source if host and target match

Some Python packages _must_ be installed from source: either PyPI
only holds source distributions of them, or lacks wheels for the
target platform. If the host platform matches the target Lambda
platform, then permit installation of Python packages from source.

src/actions/install-update.js

@@ -110,17 +110,28 @@ module.exports = function hydrator (params, callback) {
       else if (isPy) {
         let flags = ''
         if (lambda) {
-          // Technique per AWS, found that `--python-version` was essential, but `--implementation cp` may not be
-          // https://repost.aws/knowledge-center/lambda-python-package-compatible
-          // This may still not work because of glibc version differences, see:
-          // https://docs.aws.amazon.com/linux/al2023/ug/compare-with-al2.html#glibc-gcc-and-binutils
-          let arch = lambda.config.architecture === 'arm64' ? 'manylinux2014_aarch64' : 'manylinux2014_x86_64'
-          let ver = lambda.config.runtime.split('python')[1]
-          flags = '--only-binary=:all: ' +
-                  `--platform=${arch} ` +
-                  `--python-version ${ver} `
-          // Reset flags if installing from Sandbox
-          if (local) flags = ''
+          if (!local) {
+            let arch = lambda.config.architecture === 'arm64' ? 'aarch64' : 'x86_64'
+            let ver = lambda.config.runtime.split('python')[1]
+
+            let pythonPlatformCheck = child.spawnSync('python3', [ '-c', "'import platform; import sys; print(platform.system(), platform.machine(), *platform.python_version_tuple())'", ], { shell: true })
+            if (pythonPlatformCheck.status) {
+              console.error(pythonPlatformCheck.output.toString())
+              throw Error(`python3 error`)
+            }
+            let [ platformSystem, platformMachine, platformPythonVersionMajor, platformPythonVersionMinor, ] = pythonPlatformCheck.stdout.toString().trim().split(' ')
+            let isNative = platformSystem === 'Linux' && platformMachine === arch && `${platformPythonVersionMajor}.${platformPythonVersionMinor}` === ver
+
+            if (!isNative) {
+              // Technique per AWS, found that `--python-version` was essential, but `--implementation cp` may not be
+              // https://repost.aws/knowledge-center/lambda-python-package-compatible
+              // This may still not work because of glibc version differences, see:
+              // https://docs.aws.amazon.com/linux/al2023/ug/compare-with-al2.html#glibc-gcc-and-binutils
+              flags = '--only-binary=:all: ' +
+                      `--platform=manylinux2014_${arch} ` +
+                      `--python-version ${ver} `
+            }
+          }
 
           // Update Python deps
           if (!installing) {