Pixi Services¶

Three Python services orchestrated as a DAG, demonstrating health checks, restart policies, and the Krill Python SDK.

Architecture¶

data-processor          (no dependencies, always-restart)
       │
       ▼ healthy
data-analyzer           (restart on-failure, max 3)
       │
       ▼ healthy
decision-controller     (critical, restart on-failure, max 3)

Recipe¶

examples/krill-pixi.yaml

version: "1"
name: krill-pixi

env:
  ROBOT_ID: "pixi-001"
  LOG_LEVEL: "info"

services:
  data-processor:
    execute:
      type: pixi
      task: run-processor
      environment: default
      working_dir: ./services/data-processor
    dependencies: []
    health_check:
      type: heartbeat
      timeout: 10s
    policy:
      restart: always
      restart_delay: 5s

  data-analyzer:
    execute:
      type: pixi
      task: run-analyzer
      environment: default
      working_dir: ./services/data-analyzer
    dependencies:
      - data-processor: healthy
    health_check:
      type: heartbeat
      timeout: 10s
    policy:
      restart: on-failure
      max_restarts: 3
      restart_delay: 5s

  decision-controller:
    execute:
      type: pixi
      task: run-controller
      environment: default
      working_dir: ./services/decision-controller
    dependencies:
      - data-processor: healthy
      - data-analyzer: healthy
    critical: true
    health_check:
      type: heartbeat
      timeout: 15s
    policy:
      restart: on-failure
      max_restarts: 3
      restart_delay: 5s

Running¶

# Install pixi environments (first time)
cd examples/services
for d in data-processor data-analyzer decision-controller; do
  (cd "$d" && pixi install)
done

# Start
cd ../..
krill up examples/krill-pixi.yaml

What to Expect¶

data-processor starts first and begins sending heartbeats.
Once healthy, data-analyzer starts. It occasionally reports degraded status.
Once both are healthy, decision-controller starts.

Try It¶

Scenario	Command	Expected
Kill processor	`kill <pid>`	Restarts immediately, dependents keep running
Kill analyzer	`kill <pid>`	Restarts up to 3 times, controller stops
Kill controller 3+ times	`kill <pid>` (repeat)	Emergency stop — all services shut down

Key Concepts¶

type: pixi — runs a pixi task inside a managed environment
dependencies: [svc: healthy] — waits for heartbeat confirmation before starting
critical: true — failure of this service triggers a full emergency stop