Set HOME to /tmp

Author: Graham Krizek

README.md

@@ -71,7 +71,9 @@ Bash behaves in ways unlike other programming languages. As such, there are some
 
 ### Notes
 
-- Files to configure the AWS CLI are in `/tmp/.aws`. By default, the CLI uses the same region and IAM Role as your lambda function. If you need to set something different, you can use the `/tmp/.aws/config` and `/tmp/.aws/credentials` files accordingly.
+- `$HOME` is set to `/tmp`. This is because the Lambda filesystem is read-only except for the `/tmp` directory. Some programs require `$HOME` to be writeable (like the AWS CLI and some SSH commands), so this allows them to work without issue.
+
+- Files to configure the AWS CLI should be put in `/tmp/.aws`. By default, the CLI uses the same region and IAM Role as your lambda function. If you need to set something different, you can use the `/tmp/.aws/config` and `/tmp/.aws/credentials` files accordingly.
 
 - When using curl, you should use the `-s` flag. Without the silent flag, curl will send the progress bar of your request to `stderr`. This will show up in your response. So it's usually best to disable the progress bar.
 

bootstrap

@@ -5,6 +5,7 @@ set -uo pipefail
 # Constants
 RUNTIME_PATH="2018-06-01/runtime"
 mkdir -p /tmp/.aws
+export HOME="/tmp"
 
 # Send initialization error to Lambda API
 sendInitError () {
@@ -51,8 +52,6 @@ do
   export AWS_LAMBDA_DEADLINE_MS=$(grep -Fi Lambda-Runtime-Deadline-Ms "$HEADERS" | tr -d '[:space:]' | cut -d: -f2)
   export AWS_LAMBDA_FUNCTION_ARN=$(grep -Fi Lambda-Runtime-Invoked-Function-Arn "$HEADERS" | tr -d '[:space:]' | cut -d: -f2)
   export AWS_LAMBDA_TRACE_ID=$(grep -Fi Lambda-Runtime-Trace-Id "$HEADERS" | tr -d '[:space:]' | cut -d: -f2)
-  export AWS_CONFIG_FILE="/tmp/.aws/config"
-  export AWS_SHARED_CREDENTIALS_FILE="/tmp/.aws/credentials"
   # Execute the user function
   $(echo "$_HANDLER" | cut -d. -f2) "$EVENT_DATA" >&1 2> $RESPONSE | cat
   EXIT_CODE=$?