chore: add some memory debugging (aws#24970)

The build is running out of memory for unclear reasons. Add some debugging to figure out what's going on.

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

build.sh

@@ -38,6 +38,9 @@ done
 export PATH=$(npm bin):$PATH
 export NODE_OPTIONS="--max-old-space-size=8196 --experimental-worker ${NODE_OPTIONS:-}"
 
+# Temporary log memory for long builds (this may mess with tests that check stderr)
+# export NODE_OPTIONS="-r $PWD/scripts/log-memory.js ${NODE_OPTIONS:-}"
+
 if ! [ -x "$(command -v yarn)" ]; then
   echo "yarn is not installed. Install it from here- https://yarnpkg.com/en/docs/install."
   exit 1

buildspec.yaml

@@ -19,11 +19,15 @@ phases:
       # Packing aws-cdk-lib can cause memory errors. Increasing this value
       # allows our build to more consistently succeed
       - /sbin/sysctl -w vm.max_map_count=2251954
+
   pre_build:
     commands:
+      # Print our ulimits to find out if we might run into a resource limit
+      - ulimit -a
       - /bin/bash ./scripts/cache-load.sh
   build:
     commands:
+      - codebuild-breakpoint
       - 'if ${BUMP_CANDIDATE:-false}; then /bin/bash ./scripts/bump-candidate.sh; fi'
       - /bin/bash ./scripts/align-version.sh
       - /bin/bash ./build.sh

scripts/log-memory.js

@@ -0,0 +1,15 @@
+// Script to get Node.js to print its memory usage periodically
+//
+// Use as follows:
+//
+// export NODE_OPTIONS="-r $PWD/scripts/log-memory.js ${NODE_OPTIONS:-}"
+const { memoryUsage } = require('process');
+
+const MB = 1024 * 1024;
+
+setInterval(() => {
+    const now = new Date();
+    const HH = `0${now.getHours()}`.slice(-2);
+    const MM = `0${now.getMinutes()}`.slice(-2);
+    console.error(`[${HH}:${MM}] [node:${process.pid}] rss=${(memoryUsage.rss() / MB).toFixed(1)}`);
+}, 60000).unref();