Bouncer

A lightweight RPC service for distributed application control - replaces makeshift solutions using memcached or Redis.

Quick Start

Run the server:

docker run -p 5505:5505 pjwerneck/bouncer:latest

View the API documentation:

# Open Swagger UI in your browser
http://localhost:5505/docs

Examples

"I want to limit something to only one operation per second"

# Use a token bucket
curl http://localhost:5505/tokenbucket/myapp/acquire

"How to increase the limit to twenty per second?"

# Set size=20
curl http://localhost:5505/tokenbucket/myapp/acquire?size=20

"But I can't have all twenty starting at the same time!"

# Set interval to 1000/rate for smoother distribution
curl http://localhost:5505/tokenbucket/myapp/acquire?interval=50

"What if I have a resource that can be used by only one client at a time?"

# Use a semaphore
KEY=$(curl http://localhost:5505/semaphore/myapp/acquire)
# ... do work ...
curl http://localhost:5505/semaphore/myapp/release?key=$KEY

"Now I need to limit it to ten concurrent clients."

# Use a semaphore with size=10
KEY=$(curl http://localhost:5505/semaphore/myapp/acquire?size=10)
# ... do work ...
curl http://localhost:5505/semaphore/myapp/release?key=$KEY

"I have some clients that must wait for something else to finish."

# Waiting clients
curl http://localhost:5505/event/myapp/wait

# Triggering client
curl http://localhost:5505/event/myapp/send?message=wakeup

"I need to count how many times something happens across multiple services"

# Increment counter by 1
curl http://localhost:5505/counter/myapp/count

# Increment by specific amount
curl http://localhost:5505/counter/myapp/count?amount=5

# Get current value
curl http://localhost:5505/counter/myapp/value

# Reset counter
curl http://localhost:5505/counter/myapp/reset

"I want multiple clients to wait until exactly N of them are ready"

# Create a barrier for 3 clients
# Each client does:
curl http://localhost:5505/barrier/myapp/wait?size=3

# The barrier triggers automatically when the 3rd client arrives

"I need to know if a periodic task stops running"

# Monitoring clients
curl http://localhost:5505/watchdog/myapp/wait

# Task that should be monitored
while true; do
    curl http://localhost:5505/watchdog/myapp/kick?expires=60000
    sleep 30
done

# If the task fails to kick within expires time,
# all waiting clients will be notified

Configuration

Environment variables for customizing server behavior:

Variable	Default	Description
BOUNCER_HOST	0.0.0.0	Server listen address
BOUNCER_PORT	5505	Server listen port
BOUNCER_LOGLEVEL	INFO	Log level (TRACE, DEBUG,INFO,WARN,ERROR,FATAL,PANIC)
BOUNCER_READ_TIMEOUT	30	HTTP read timeout (seconds)
BOUNCER_WRITE_TIMEOUT	30	HTTP write timeout (seconds)

Warning

If your controllers require a maxwait time that exceeds the default write timeout of 30 seconds, increase the BOUNCER_WRITE_TIMEOUT value accordingly, otherwise the server might close the connection before the response is available