Launcher script breaks at high numbers of sites (#414)

Launcher script breaks at high numbers of sites (#414)

On a multi-site app configuration files such as containers/web.yml grow with the number of sites. We discovered that the launcher script breaks at around 100 sites due to “Argument List too long” when commands such ‘echo’ are being referenced from the within the exec call.

This workaround echoes the “$input” content outside the exec (which we verified works fine for 300 sites) and then cats the file content inside the exec. Thus bypassing the argument limitation. Finally, we remove the temporary file generated.

diff --git a/launcher b/launcher
index 4c16489..06588fd 100755
--- a/launcher
+++ b/launcher
@@ -335,7 +335,12 @@ set_template_info() {
     puts env.map{|k,v| "-e\n#{k}=#{v}" }.join("\n")
 RUBY
 
-    raw=`exec echo "$input" | $docker_path run $user_args --rm -i -a stdin -a stdout $image ruby -e "$env_ruby"`
+    tmp_input_file=$(mktemp)
+
+    echo "$input" > "$tmp_input_file"
+    raw=`exec cat "$tmp_input_file" | $docker_path run $user_args --rm -i -a stdin -a stdout $image ruby -e "$env_ruby"`
+
+    rm -f "$tmp_input_file"
 
     env=()
     ok=1
@@ -374,7 +379,12 @@ RUBY
     puts labels.map{|k,v| "-l\n#{k}=#{v}" }.join("\n")
 RUBY
 
-    raw=`exec echo "$input" | $docker_path run $user_args --rm -i -a stdin -a stdout $image ruby -e "$labels_ruby"`
+    tmp_input_file=$(mktemp)
+
+    echo "$input" > "$tmp_input_file"
+    raw=`exec cat "$tmp_input_file" | $docker_path run $user_args --rm -i -a stdin -a stdout $image ruby -e "$labels_ruby"`
+
+    rm -f "$tmp_input_file"
 
     labels=()
     ok=1
@@ -622,9 +632,15 @@ run_bootstrap() {
   echo $run_command
 
   unset ERR
-  (exec echo "$input" | $docker_path run --shm-size=512m $user_args $links "${env[@]}" -e DOCKER_HOST_IP="$docker_ip" --cidfile $cidbootstrap -i -a stdin -a stdout -a stderr $volumes $image \
+
+  tmp_input_file=$(mktemp)
+
+  echo "$input" > "$tmp_input_file"
+  (exec cat "$tmp_input_file" | $docker_path run --shm-size=512m $user_args $links "${env[@]}" -e DOCKER_HOST_IP="$docker_ip" --cidfile $cidbootstrap -i -a stdin -a stdout -a stderr $volumes $image \
     /bin/bash -c "$run_command") || ERR=$?
 
+  rm -f "$tmp_input_file"
+
   unset FAILED
   # magic exit code that indicates a retry
   if [[ "$ERR" == 77 ]]; then

GitHub sha: fb827907

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