lifecycle-tester

README

Lifecycle Tester

Lifecycle Tester is a lightweight web application designed to test the feature in Kubernetes deployments. It can be used in a container to simulate different application states and observe how Kubernetes behaves when the application is not considered "ready".

The application provides the following endpoints:

endpoint	description
GET /	Returns the current state and request details.
POST /	Updates the application state based on the provided JSON payload.
GET /readiness	Returns an HTTP 200 status code when the application is considered "ready" and an HTTP 503 status code when it's not.
GET /liveness	Returns an HTTP 200 status code when the application is considered "live" and an HTTP 503 status code when it's not.

State

The server's state is controlled by a JSON payload sent to the POST / endpoint. The state object has the following fields:

• is_failed_readiness (bool): If set to true, the server will fail health checks at the /readiness endpoint.
• is_failed_liveness (bool): If set to true, the server will fail health checks at the /liveness endpoint.
• shutdown_delay_seconds (int64): The number of seconds to delay the server shutdown process after receiving a shutdown signal.

Environment Variables

The Lifecycle Tester application can be configured using the following environment variables:

Environment Variable	Description	Default
DISABLE_HEALTH_LOG	Set to "true" to disable logging of health check requests	"false"
SHUTDOWN_DELAY_SECONDS	Number of seconds to delay the server shutdown process after receiving a shutdown signal	"0"
READINESS_DELAY_SECONDS	Number of seconds to delay the server readiness state	"0"
LIVENESS_DELAY_SECONDS	Number of seconds to delay the server liveness state	"0"

Usage

Web API

This request will return the server information, including the hostname, request details, and current state.

curl http://localhost:8080

This request will set is_failed_liveness to true, causing the server to fail health checks, and shutdown_delay_seconds to 30, causing the server to delay the shutdown process by 30 seconds after receiving a shutdown signal.

curl -X POST -H "Content-Type: application/json" -d '{"is_failed_liveness": true, "shutdown_delay_seconds": 30}' http://localhost:8080

CLI Usage

The CLI tool provides various subcommands for different functionalities:

• server: Start the HTTP server to provide an interface for updating the application's state and handling container lifecycle events.
• state: Update the application's state, such as changing the status of readiness and liveness probes.
• sleep: Make the application sleep for a specified duration in seconds or indefinitely using the 'infinity' keyword.

Server

This command will start the HTTP server.

lifecycle-tester server

State

This command will set is_failed_readiness to true, causing the server to fail health checks at the /readiness endpoint, and shutdown_delay_seconds to 30, causing the server to delay the shutdown process by 30 seconds after receiving a shutdown signal.

lifecycle-tester state --is-failed-readiness=true --shutdown-delay-seconds=30

Sleep

This command will make the application sleep for 10 seconds.

lifecycle-tester sleep 10

This command will make the application sleep indefinitely.

lifecycle-tester sleep infinity