README.md

title	keywords	description
Tableflip Example	tableflip golang graceful upgrade	Use tableflip for graceful upgrades in a Go application.

Tableflip Example

This example demonstrates how to use tableflip for graceful upgrades in a Go application.

What is Tableflip?

Tableflip is a library that allows you to update the running code and/or configuration of a network service without disrupting existing connections. It achieves this by starting a new process, transferring clients to it, and then exiting the old process.

Goals of Tableflip

• No old code keeps running after a successful upgrade.
• The new process has a grace period for initialization.
• Crashing during initialization is acceptable.
• Only a single upgrade is ever run in parallel.
• Tableflip works on Linux and macOS.

Steps

1. Build v0.0.1 Demo:

   go build -o demo main.go

2. Run the Demo and Create a GET Request to 127.0.0.1:8080/version:

   [PID: 123] v0.0.1

3. Prepare a New Version:

• Change the main.go to update the version to "v0.0.2".
• Rebuild the demo:

  go build -o demo main.go

4. Kill the Old Process:

   kill -s HUP 123

5. Create the Request to the Version API Again:

   [PID: 123] v0.0.2

The client is completely immune to server upgrades and reboots, and our application updates gracefully!