Read container memory limit from cgroup (v1 and v2)

Uses memory.high if available (recommended way of setting a functioning soft limit), then first falls back to memory.max (e.g. from 'docker run -m'), then to memory.low (e.g. from 'docker run --memory-reservation'), and finally to memory.min.

Falls back to direct reading of '/sys/fs/cgroup/memory/memory.limit_in_bytes' for cases where that exists, but no full cgroupfs is mounted (e.g. on Heroku).

Limit enforcement (now to 8 TB) is still in place this way - a Docker v1 value will be read, and run into the limit for unrestricted containers, without hitting the fallback and getting returned.

GUS-W-16052317

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 - Added Yarn version 4.3.1.
 - Added Yarn version 3.8.3.
+- Support reading container memory limits from cgroups (v1 and v2)
 
 ## [v255] - 2024-06-21
 

lib/environment.sh

@@ -86,7 +86,14 @@ write_profile() {
   local bp_dir="$1"
   local build_dir="$2"
   mkdir -p "$build_dir/.profile.d"
-  cp "$bp_dir"/profile/* "$build_dir/.profile.d/"
+  cp "$bp_dir"/profile/nodejs.sh "$build_dir/.profile.d/"
+  write_web_concurrency "$bp_dir" "$build_dir/.profile.d/WEB_CONCURRENCY.sh"
+}
+
+write_web_concurrency() {
+  local bp_dir="$1"
+  # concatenate these two together
+  cat "$bp_dir"/etc/cgroups.sh "$bp_dir"/profile/WEB_CONCURRENCY.sh > "$2"
 }
 
 write_ci_profile() {

profile/WEB_CONCURRENCY.sh

@@ -31,17 +31,28 @@ log_concurrency() {
 detect_memory() {
   local default=$1
 
-  if [ -e /sys/fs/cgroup/memory/memory.limit_in_bytes ]; then
-    echo $(($(cat /sys/fs/cgroup/memory/memory.limit_in_bytes) / 1048576))
+  local memory_limit
+  memory_limit=$(cgroup_util_read_cgroup_memory_limit_with_fallback) && {
+    echo $(( memory_limit / 1024 / 1024 ))
+    return
+  }
+
+  if (($? == 99)); then
+    dne_memory
   else
     echo "$default"
-  fi
+	fi
+}
+
+dne_memory() {
+	echo "129024"
 }
 
 bound_memory() {
   local detected=$1
   # Memory is bound to the maximum memory of known dyno types: ~126 GB
-  local max_detected_memory=129024
+  local max_detected_memory
+  max_detected_memory=$(dne_memory)
   if (( detected > max_detected_memory )); then
     echo "$max_detected_memory"
   else

test/run

@@ -557,35 +557,55 @@ testBuildWithUserCacheDirectoriesCamel() {
 }
 
 testConcurrency1X() {
-  LOG_CONCURRENCY=true MEMORY_AVAILABLE=512 capture "$(pwd)"/profile/WEB_CONCURRENCY.sh
+  # write_web_concurrency concatenates a vendored library file and our own logic into one file
+  WEB_CONCURRENCY_SH=$(mktemp)
+  chmod u+x "$WEB_CONCURRENCY_SH"
+  write_web_concurrency "$(pwd)" "$WEB_CONCURRENCY_SH"
+  LOG_CONCURRENCY=true MEMORY_AVAILABLE=512 capture "$WEB_CONCURRENCY_SH"
   assertCaptured "Detected 512 MB available memory, 512 MB limit per process (WEB_MEMORY)"
   assertCaptured "Recommending WEB_CONCURRENCY=1"
   assertCapturedSuccess
 }
 
 testConcurrency2X() {
-  LOG_CONCURRENCY=true MEMORY_AVAILABLE=1024 capture "$(pwd)"/profile/WEB_CONCURRENCY.sh
+  # write_web_concurrency concatenates a vendored library file and our own logic into one file
+  WEB_CONCURRENCY_SH=$(mktemp)
+  chmod u+x "$WEB_CONCURRENCY_SH"
+  write_web_concurrency "$(pwd)" "$WEB_CONCURRENCY_SH"
+  LOG_CONCURRENCY=true MEMORY_AVAILABLE=1024 capture "$WEB_CONCURRENCY_SH"
   assertCaptured "Detected 1024 MB available memory, 512 MB limit per process (WEB_MEMORY)"
   assertCaptured "Recommending WEB_CONCURRENCY=2"
   assertCapturedSuccess
 }
 
 testConcurrencyPerformanceM() {
-  LOG_CONCURRENCY=true MEMORY_AVAILABLE=2560 capture "$(pwd)"/profile/WEB_CONCURRENCY.sh
+  # write_web_concurrency concatenates a vendored library file and our own logic into one file
+  WEB_CONCURRENCY_SH=$(mktemp)
+  chmod u+x "$WEB_CONCURRENCY_SH"
+  write_web_concurrency "$(pwd)" "$WEB_CONCURRENCY_SH"
+  LOG_CONCURRENCY=true MEMORY_AVAILABLE=2560 capture "$WEB_CONCURRENCY_SH"
   assertCaptured "Detected 2560 MB available memory, 512 MB limit per process (WEB_MEMORY)"
   assertCaptured "Recommending WEB_CONCURRENCY=5"
   assertCapturedSuccess
 }
 
 testConcurrencyPerformanceL() {
-   LOG_CONCURRENCY=true MEMORY_AVAILABLE=14336 capture "$(pwd)"/profile/WEB_CONCURRENCY.sh
-   assertCaptured "Detected 14336 MB available memory, 512 MB limit per process (WEB_MEMORY)"
-   assertCaptured "Recommending WEB_CONCURRENCY=28"
-   assertCapturedSuccess
+  # write_web_concurrency concatenates a vendored library file and our own logic into one file
+  WEB_CONCURRENCY_SH=$(mktemp)
+  chmod u+x "$WEB_CONCURRENCY_SH"
+  write_web_concurrency "$(pwd)" "$WEB_CONCURRENCY_SH"
+  LOG_CONCURRENCY=true MEMORY_AVAILABLE=14336 capture "$WEB_CONCURRENCY_SH"
+  assertCaptured "Detected 14336 MB available memory, 512 MB limit per process (WEB_MEMORY)"
+  assertCaptured "Recommending WEB_CONCURRENCY=28"
+  assertCapturedSuccess
 }
 
 testConcurrencyCustomLimit() {
-  LOG_CONCURRENCY=true MEMORY_AVAILABLE=1024 WEB_MEMORY=256 capture "$(pwd)"/profile/WEB_CONCURRENCY.sh
+  # write_web_concurrency concatenates a vendored library file and our own logic into one file
+  WEB_CONCURRENCY_SH=$(mktemp)
+  chmod u+x "$WEB_CONCURRENCY_SH"
+  write_web_concurrency "$(pwd)" "$WEB_CONCURRENCY_SH"
+  LOG_CONCURRENCY=true MEMORY_AVAILABLE=1024 WEB_MEMORY=256 capture "$WEB_CONCURRENCY_SH"
   assertCaptured "Detected 1024 MB available memory, 256 MB limit per process (WEB_MEMORY)"
   assertCaptured "Recommending WEB_CONCURRENCY=4"
   assertCapturedSuccess
@@ -594,7 +614,11 @@ testConcurrencyCustomLimit() {
 # When /sys/fs/cgroup/memory/memory.limit_in_bytes lies and gives a ridiculous value
 # This happens on Dokku for example
 testConcurrencyTooHigh() {
-  LOG_CONCURRENCY=true MEMORY_AVAILABLE=10000000000 capture "$(pwd)"/profile/WEB_CONCURRENCY.sh
+  # write_web_concurrency concatenates a vendored library file and our own logic into one file
+  WEB_CONCURRENCY_SH=$(mktemp)
+  chmod u+x "$WEB_CONCURRENCY_SH"
+  write_web_concurrency "$(pwd)" "$WEB_CONCURRENCY_SH"
+  LOG_CONCURRENCY=true MEMORY_AVAILABLE=10000000000 capture "$WEB_CONCURRENCY_SH"
   assertCaptured "Could not determine a reasonable value for WEB_CONCURRENCY"
   assertCaptured "Recommending WEB_CONCURRENCY=1"
   assertCapturedSuccess