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Tasks Overview

Tasks are reusable automation workflows that encapsulate complex operations into simple, parameterized commands. They form the backbone of Xec's automation capabilities, enabling you to define once and execute anywhere.

What Are Tasks?​

Tasks are named sequences of commands that can:

  • Execute across multiple targets
  • Accept parameters
  • Handle errors gracefully
  • Run steps conditionally
  • Execute in parallel
  • Emit and respond to events
  • Be composed into larger workflows

Basic Task Structure​

tasks:
  # Simple command task
  hello:
    command: echo "Hello, World!"
  
  # Multi-step task
  deploy:
    description: Deploy application
    steps:
      - command: git pull
      - command: npm install
      - command: npm run build
      - command: pm2 restart app

Task Types​

1. Command Tasks​

Single command execution:

tasks:
  backup:
    command: tar -czf backup.tar.gz /data
    target: backup-server

2. Script Tasks​

Execute scripts:

tasks:
  process:
    script: |
      const data = await fetchData();
      const processed = transform(data);
      await save(processed);
    description: Process data pipeline

3. Multi-Step Tasks​

Complex workflows:

tasks:
  release:
    steps:
      - name: Run tests
        command: npm test
      - name: Build application
        command: npm run build
      - name: Deploy to production
        task: deploy-prod

4. Parallel Tasks​

Concurrent execution:

tasks:
  health-check:
    parallel: true
    targets:
      - hosts.web-1
      - hosts.web-2
      - hosts.web-3
    command: curl http://localhost/health

Task Parameters​

Accept input parameters:

tasks:
  scale:
    description: Scale deployment
    params:
      - name: replicas
        type: number
        required: true
        min: 1
        max: 10
        description: Number of replicas
    command: |
      kubectl scale deployment/app \
        --replicas=${params.replicas}

Task Composition​

Build complex tasks from simpler ones:

tasks:
  setup:
    steps:
      - command: apt-get update
      - command: apt-get install -y nginx
  
  deploy:
    steps:
      - task: setup
      - command: cp app.conf /etc/nginx/
      - command: systemctl restart nginx

Error Handling​

Control error behavior:

tasks:
  resilient:
    steps:
      - command: test-connection
        onFailure:
          retry: 3
          delay: 5s
      
      - command: critical-operation
        onFailure: abort
      
      - command: optional-cleanup
        onFailure: continue

Conditional Execution​

Execute steps conditionally:

tasks:
  smart-deploy:
    steps:
      - command: check-health
        register: health_status
      
      - command: deploy-blue
        when: health_status.exitCode != 0
      
      - command: deploy-green
        when: health_status.exitCode == 0

Task Hooks​

Execute code at specific points:

tasks:
  monitored:
    hooks:
      before:
        - command: echo "Starting task..."
      after:
        - command: echo "Task completed"
      onError:
        - command: send-alert
    
    command: critical-operation

Event System​

Emit and respond to events:

tasks:
  producer:
    command: process-data
    emits:
      - name: data-processed
        data: { status: "complete" }
  
  consumer:
    on:
      data-processed: |
        echo "Data processing complete"

Task Scheduling​

Schedule recurring tasks:

tasks:
  backup:
    schedule: "0 2 * * *"  # 2 AM daily
    command: backup.sh
    
  cleanup:
    schedule: "@hourly"
    command: clean-temp-files.sh

Task Templates​

Create reusable patterns:

tasks:
  $template-deploy:
    params:
      - name: service
        required: true
    steps:
      - command: docker pull ${params.service}:latest
      - command: docker stop ${params.service}
      - command: docker run -d ${params.service}:latest
  
  deploy-web:
    template: $template-deploy
    params:
      service: web-app
  
  deploy-api:
    template: $template-deploy
    params:
      service: api-server

Task Dependencies​

Define execution order:

tasks:
  prepare:
    command: setup-environment
  
  build:
    dependsOn: [prepare]
    command: compile-code
  
  test:
    dependsOn: [build]
    command: run-tests
  
  deploy:
    dependsOn: [test]
    command: deploy-application

Task Caching​

Cache task results:

tasks:
  expensive-operation:
    command: generate-report
    cache:
      key: "report-${params.date}"
      ttl: 3600  # 1 hour
      storage: redis

Private Tasks​

Hide internal tasks:

tasks:
  _internal-setup:  # Prefix with underscore
    private: true
    command: internal-configuration
  
  public-task:
    steps:
      - task: _internal-setup
      - command: public-operation

Task Execution​

Direct Execution​

# Execute task
xec run deploy

# With parameters
xec run scale --replicas 5

# On specific target
xec run backup --target hosts.backup-server

From Configuration​

# Reference in other tasks
tasks:
  full-deploy:
    steps:
      - task: test
      - task: build
      - task: deploy

From Scripts​

// In xec scripts
await xec.run('deploy', {
  params: { version: '1.2.3' }
});

Task Variables​

Access task context:

tasks:
  context-aware:
    command: |
      echo "Task: ${task.name}"
      echo "Target: ${target.name}"
      echo "Profile: ${profile}"
      echo "Param: ${params.value}"

Best Practices​

1. Single Responsibility​

# Good - focused tasks
tasks:
  test:
    command: npm test
  build:
    command: npm run build

# Bad - doing too much
tasks:
  do-everything:
    command: npm test && npm build && deploy

2. Descriptive Names​

# Good
tasks:
  deploy-production-api:
    description: Deploy API to production cluster

# Bad
tasks:
  d-p-a:  # Unclear

3. Parameter Validation​

tasks:
  validated:
    params:
      - name: environment
        type: enum
        values: [dev, staging, prod]
        required: true

4. Error Recovery​

tasks:
  resilient:
    steps:
      - command: risky-operation
        onFailure:
          retry: 3
          task: recovery-task

5. Documentation​

tasks:
  complex-migration:
    description: |
      Performs database migration with backup.
      WARNING: This task modifies production data.
      Duration: ~15 minutes
      Required permissions: DBA role

Common Patterns​

Deployment Pipeline​

tasks:
  ci-pipeline:
    steps:
      - name: Checkout code
        command: git pull origin main
      
      - name: Install dependencies
        command: npm ci
      
      - name: Run tests
        command: npm test
        onFailure: abort
      
      - name: Build application
        command: npm run build
      
      - name: Deploy
        task: deploy-${params.environment}

Health Monitoring​

tasks:
  monitor-services:
    parallel: true
    targets:
      - hosts.web-server
      - hosts.api-server
      - hosts.db-server
    steps:
      - command: check-service-health
      - command: check-disk-space
      - command: check-memory-usage

Backup Strategy​

tasks:
  backup-all:
    steps:
      - name: Backup database
        task: backup-db
        target: hosts.db-server
      
      - name: Backup files
        task: backup-files
        target: hosts.file-server
      
      - name: Verify backups
        task: verify-backups
        target: hosts.backup-server

Advanced Features​

Dynamic Task Generation​

tasks:
  deploy-all:
    script: |
      const services = await getServices();
      for (const service of services) {
        await xec.run('deploy', {
          params: { service: service.name }
        });
      }

Task Middleware​

tasks:
  authenticated:
    middleware:
      - auth-check
      - rate-limit
    command: sensitive-operation

Task Metrics​

tasks:
  monitored:
    metrics:
      enabled: true
      collector: prometheus
    command: important-operation

Troubleshooting​

Task Not Found​

# List available tasks
xec task list

# Check task definition
xec config show --tasks

Parameter Issues​

# Show task parameters
xec task info deploy

# Validate parameters
xec run deploy --dry-run --replicas 5

Execution Failures​

# Debug mode
xec run deploy --debug

# Verbose output
xec run deploy --verbose

Next Steps​

See Also​