To support java17 runtime, substitute wrapper handler for original in exec command line (aws-observability#944)

* To support java17 runtime, Substitute wrapper handler for original in exec command line

* Add comment describing the bash string replacement incantation

Author: johnbley

java/layer-wrapper/scripts/otel-handler

@@ -9,4 +9,6 @@ fi
 
 export OTEL_INSTRUMENTATION_AWS_LAMBDA_FLUSH_TIMEOUT=10000
 
-exec "$@"
+# java17 runtime puts the handler to run as a command line argument and seems to prefer
+# this over _HANDLER, so apply a regex to replace the original handler name with our wrapper
+exec "${@//$OTEL_INSTRUMENTATION_AWS_LAMBDA_HANDLER/$_HANDLER}"

java/layer-wrapper/scripts/otel-proxy-handler

@@ -9,4 +9,6 @@ fi
 
 export OTEL_INSTRUMENTATION_AWS_LAMBDA_FLUSH_TIMEOUT=10000
 
-exec "$@"
+# java17 runtime puts the handler to run as a command line argument and seems to prefer
+# this over _HANDLER, so apply a regex to replace the original handler name with our wrapper
+exec "${@//$OTEL_INSTRUMENTATION_AWS_LAMBDA_HANDLER/$_HANDLER}"

java/layer-wrapper/scripts/otel-sqs-handler

@@ -9,4 +9,6 @@ fi
 
 export OTEL_INSTRUMENTATION_AWS_LAMBDA_FLUSH_TIMEOUT=10000
 
-exec "$@"
+# java17 runtime puts the handler to run as a command line argument and seems to prefer
+# this over _HANDLER, so apply a regex to replace the original handler name with our wrapper
+exec "${@//$OTEL_INSTRUMENTATION_AWS_LAMBDA_HANDLER/$_HANDLER}"

java/layer-wrapper/scripts/otel-stream-handler

@@ -9,4 +9,6 @@ fi
 
 export OTEL_INSTRUMENTATION_AWS_LAMBDA_FLUSH_TIMEOUT=10000
 
-exec "$@"
+# java17 runtime puts the handler to run as a command line argument and seems to prefer
+# this over _HANDLER, so apply a regex to replace the original handler name with our wrapper
+exec "${@//$OTEL_INSTRUMENTATION_AWS_LAMBDA_HANDLER/$_HANDLER}"