profile.sh - Harness script for remotely profiling node process on AWS EC2 instances

profile.sh

#!/bin/bash
#
# See: https://mixmax.com/blog/determining-why-that-server-is-on-fire for details.
#
# Example usage: ./profile.sh $INSTANCE_ID [$DURATION] [$PID]
# Where:
#   - $INSTANCE_ID is the EC2 identifier of the instance to profile the node
#     processes on.
#   - $DURATION is an optional duration specified in seconds (defaults to 30).
#   - $PID is a specific process ID to profile, by default we profile all `node`
#     process on the remote instance.
#
# It is also assumed that you have setup your AWS credentials so that the
# `aws` cli functions correctly.
#
# This script currently assumes that you are profiling EC2 instances inside
# a private VPC and that you ahve setup a bastion tier with SSH forwarding
# appropriately. If this is not the case, simply change
# s/PrivateDnsName/PublicDnsName/.
#
##########

set -e

INSTANCE=$1
DURATION=${2:-30}
PID_MATCHER="echo $3"
if [ -z ${3+x} ]; then
    PID_MATCHER='pgrep node | xargs | sed -e "s\/ \/,\/g"'
fi

echo "building perf script..."
sed -e "s/DURATION/$DURATION/g" perf.sh > perf.tmp.sh
sed -i -e "s/PID_MATCHER/$PID_MATCHER/g" perf.tmp.sh

IP=$(aws ec2 describe-instances --instance-ids $INSTANCE --query "Reservations[*].Instances[*].PrivateDnsName" --output text)

# Collect a sample from the remote node
echo "running the debug script on the remote node: $INSTANCE"
ssh ec2-user@$IP 'bash -s' < perf.tmp.sh

# Cleanup after ourselves
rm -f perf.tmp.sh perf.tmp.sh-e

# Retrieve the svg from remote node
echo "copying the flamegraph back from the remote node..."
scp ec2-user@$IP:/home/ec2-user/flame.svg .

# Open the image in the browser
echo "opening the flamegraph in Chrome..."
open flame.svg -a Google\ Chrome