probe

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A powerful YAML-based workflow automation tool designed for testing, monitoring, and automation tasks. Probe uses plugin-based actions to execute workflows, making it highly flexible and extensible.

Quick Start

name: API Health Check
jobs:
- name: Check API Status
  steps:
  - name: Ping API
    uses: http
    with:
      url: https://api.example.com
      get: /health
    test: res.code == 200

probe health-check.yml

Features

• Simple YAML Syntax: Easy-to-read workflow definitions
• Plugin Architecture: Built-in HTTP, Database, Browser, Shell, SSH, SMTP, IMAP, and Hello actions with extensibility
• Job Dependencies: Control execution order with needs
• Step Outputs: Share data between steps and jobs using outputs
• Repetition: Repeat jobs with configurable intervals
• Iteration: Execute steps with different variable sets
• Expression Engine: Powerful templating and condition evaluation
• Testing Support: Built-in assertion system
• Timing Controls: Wait conditions and delays
• Rich Output: Buffered, consistent output formatting
• Security: Safe expression evaluation with timeout protection

Installation

Using Go

go install github.com/linyows/probe/cmd/probe@latest

From Source

git clone https://github.com/linyows/probe.git
cd probe
go build -o probe ./cmd/probe

Usage

Basic Usage

# Run a workflow
probe ./workflow.yml

# Verbose output
probe ./workflow.yml --verbose

# Show response times
probe ./workflow.yml --rt

# Show job dependency graph as ASCII art
probe ./workflow.yml --dag-ascii

# Show job dependency graph in Mermaid format
probe ./workflow.yml --dag-mermaid

CLI Options

• <workflow>: Specify YAML workflow file path
• --verbose: Enable detailed output
• --rt: Show response times
• --dag-ascii: Display job dependency graph as ASCII art
• --dag-mermaid: Display job dependency graph in Mermaid format
• --help: Show help information

Workflow Syntax

Basic Structure

name: Workflow Name
description: Optional description
vars:
  global_var: value
jobs:
- name: Job Name
  steps:
  - name: Step Name
    uses: action_name
    with:
      param: value

Jobs

Jobs are executed in parallel by default. Use needs for dependencies:

jobs:
- name: Setup
  id: setup
  steps:
  - name: Initialize
    uses: http
    with:
      post: /setup

- name: Test
  needs: [setup]  # Wait for setup to complete
  steps:
  - name: Run test
    uses: http
    with:
      get: /test

Steps

Steps within a job execute sequentially:

steps:
- name: Login
  id: login
  uses: http
  with:
    post: /auth/login
    body:
      username: admin
      password: secret
  outputs:
    token: res.body.token

- name: Get Profile
  uses: http
  with:
    get: /profile
    headers:
      authorization: "Bearer {{outputs.login.token}}"
  test: res.code == 200

Variables and Expressions

Use {{expression}} syntax for dynamic values:

vars:
  api_url: https://api.example.com
  user_id: 123

steps:
- name: Get User
  uses: http
  with:
    url: "{{vars.api_url}}"
    get: "/users/{{vars.user_id}}"
  test: res.body.id == vars.user_id

Built-in Functions

test: |
  res.code == 200 &&
  match_json(res.body, vars.expected) &&
  random_int(10) > 5

Available functions:

• match_json(actual, expected): JSON pattern matching with regex support
• diff_json(actual, expected): Show differences between JSON objects
• random_int(max): Generate random integer
• random_str(length): Generate random string
• unixtime(): Current Unix timestamp

Output Management

Share data between steps and jobs:

- name: Get Token
  id: auth
  uses: http
  with:
    post: /auth
  outputs:
    token: res.body.access_token
    expires: res.body.expires_in

- name: Use Token
  uses: http
  with:
    get: /protected
    headers:
      authorization: "Bearer {{outputs.auth.token}}"

Iteration

Execute steps with different variable sets:

- name: Test Multiple Users
  uses: http
  with:
    post: /users
    body:
      name: "{{vars.name}}"
      role: "{{vars.role}}"
  test: res.code == 201
  iteration:
  - {name: "Alice", role: "admin"}
  - {name: "Bob", role: "user"}
  - {name: "Carol", role: "editor"}

Job Repetition

Repeat entire jobs with intervals:

- name: Health Check
  repeat:
    count: 10
    interval: 30s
  steps:
  - name: Ping
    uses: http
    with:
      get: /health
    test: res.code == 200

Conditional Execution

Skip steps based on conditions:

- name: Conditional Step
  uses: http
  with:
    get: /api/data
  skipif: vars.skip_test == true
  test: res.code == 200

Timing and Delays

- name: Wait and Check
  uses: http
  with:
    get: /status
  wait: 5s  # Wait before execution
  test: res.code == 200

Built-in Actions

HTTP Action

- name: HTTP Request
  uses: http
  with:
    url: https://api.example.com
    # GET, POST, PUT, DELETE, etc.
    post: /
    headers:
      content-type: application/json
      authorization: Bearer token
    body:
      key: value
    timeout: 30s

SMTP Action

- name: Send Email
  uses: smtp
  with:
    addr: smtp.example.com:587
    from: sender@example.com
    to: recipient@example.com
    subject: Test Email
    body: Email content
    my-hostname: localhost

Database Action

- name: Database Query
  uses: db
  with:
    dsn: "mysql://user:password@localhost:3306/database"
    query: "SELECT * FROM users WHERE active = ?"
    params: [true]
    timeout: 30s
  test: res.code == 0 && res.rows_affected > 0

Supported databases:

• MySQL: mysql://user:pass@host:port/database
• PostgreSQL: postgres://user:pass@host:port/database?sslmode=disable
• SQLite: file:./testdata/sqlite.db or /absolute/path/database

Browser Action

- name: Web Automation
  uses: browser
  with:
    action: navigate
    url: "https://example.com"
    headless: true
    timeout: 30s
  test: res.success == "true"

Supported actions:

• navigate: Navigate to URL
• text: Extract text content from elements
• value: Get input field values
• get_attribute: Get element attribute values
• get_html: Extract HTML content from elements
• click: Click on elements
• double_click: Double-click on elements
• right_click: Right-click on elements
• hover: Hover over elements
• focus: Set focus to elements
• type / send_keys: Type text into input fields
• select: Select dropdown options
• submit: Submit forms
• scroll: Scroll elements into view
• screenshot: Capture element screenshots
• capture_screenshot: Capture full page screenshots
• full_screenshot: Capture full page screenshots with quality settings
• wait_visible: Wait for elements to become visible
• wait_not_visible: Wait for elements to become invisible
• wait_ready: Wait for page to be ready
• wait_text: Wait for specific text to appear
• wait_enabled: Wait for elements to become enabled

Shell Action

- name: Run Build Script
  uses: shell
  with:
    cmd: "npm run build"
    workdir: "/app"
    shell: "/bin/bash"
    timeout: "5m"
    env:
      NODE_ENV: production
  test: res.code == 0 && (res.stdout | contains("Build successful"))

SSH Action

- name: Deploy Application
  uses: ssh
  with:
    host: "prod.example.com"
    port: 22
    user: "deploy"
    # Authentication methods (use either password or key_file)
    password: "secure_password"
    # key_file: "~/.ssh/deploy_key"
    # key_passphrase: "key_passphrase"  # if key is encrypted
    cmd: |
      cd /opt/myapp
      git pull origin main
      systemctl restart myapp
    timeout: "300s"
    workdir: "/opt/myapp"
    # Environment variables
    env:
      DEPLOY_ENV: production
      APP_VERSION: v1.2.3
    # Security settings
    strict_host_check: true
    known_hosts: "~/.ssh/known_hosts"
  test: res.code == 0 && !contains(res.stderr, "error")

IMAP Action

- name: Email Operations
  uses: imap
  with:
    host: "imap.example.com"
    port: 993
    username: "user@example.com"
    password: "password"
    tls: true
    timeout: 30s
    strict_host_check: true
    insecure_skip_tls: false
    commands:
    - name: "select"
      mailbox: "INBOX"
    - name: "search"
      criteria:
        since: "today"
        flags: ["unseen"]
    - name: "fetch"
      sequence: "*"
      dataitem: "ALL"
  test: res.code == 0 && res.data.search.count > 0

Supported IMAP commands:

• select: Select a mailbox for read-write operations
• examine: Select a mailbox for read-only operations
• search: Search messages using criteria
• uid search: Search using UID instead of sequence numbers
• list: List available mailboxes
• fetch: Fetch message data
• uid fetch: Fetch using UID instead of sequence numbers
• store: Store message flags (basic implementation)
• uid store: Store using UID (basic implementation)
• copy: Copy messages to another mailbox (basic implementation)
• uid copy: Copy using UID (basic implementation)
• create: Create a new mailbox
• delete: Delete a mailbox
• rename: Rename a mailbox
• subscribe: Subscribe to a mailbox
• unsubscribe: Unsubscribe from a mailbox
• noop: No operation (keepalive)

Search criteria support:

• seq_nums: Sequence number ranges (e.g., "1:10", "*")
• uids: UID ranges for UID search commands
• since: Messages received since date ("today", "yesterday", "2024-01-01", "1 hour ago")
• before: Messages received before date
• sent_since: Messages sent since date
• sent_before: Messages sent before date
• headers: Header field matches (e.g., {"from": "sender@example.com"})
• bodies: Body text contains
• texts: Text (headers + body) contains
• flags: Message flags (e.g., ["seen", "answered"])
• not_flags: Messages without these flags

Hello Action (Testing)

- name: Test Action
  uses: hello
  with:
    name: World

Advanced Examples

REST API Testing

name: User API Test
vars:
  base_url: https://api.example.com
  admin_token: "{{env.ADMIN_TOKEN}}"

jobs:
- name: User CRUD Operations
  defaults:
    http:
      url: "{{vars.base_url}}"
      headers:
        authorization: "Bearer {{vars.admin_token}}"
        content-type: application/json

  steps:
  - name: Create User
    id: create
    uses: http
    with:
      post: /users
      body:
        name: Test User
        email: test@example.com
    test: res.code == 201
    outputs:
      user_id: res.body.id

  - name: Get User
    uses: http
    with:
      get: "/users/{{outputs.create.user_id}}"
    test: |
      res.code == 200 &&
      res.body.name == "Test User"

  - name: Update User
    uses: http
    with:
      put: "/users/{{outputs.create.user_id}}"
      body:
        name: Updated User
    test: res.code == 200

  - name: Delete User
    uses: http
    with:
      delete: "/users/{{outputs.create.user_id}}"
    test: res.code == 204

Load Testing with Repetition

name: Load Test
jobs:
- name: Concurrent Requests
  repeat:
    count: 100
    interval: 100ms
  steps:
  - name: API Call
    uses: http
    with:
      url: https://api.example.com
      get: /endpoint
    test: res.code == 200

Multi-Service Integration

name: E2E Test
jobs:
- name: Setup Database
  id: db-setup
  steps:
  - name: Initialize
    uses: http
    with:
      post: http://db-service/init

- name: API Tests
  needs: [db-setup]
  steps:
  - name: Test API
    uses: http
    with:
      get: http://api-service/data
    test: res.code == 200

- name: Cleanup
  needs: [db-setup]
  steps:
  - name: Reset Database
    uses: http
    with:
      post: http://db-service/reset

Expression Reference

Context Variables

• vars.*: Workflow and step variables (including environment variables defined in vars)
• res.*: Previous step response
• req.*: Previous step request
• outputs.*: Step outputs

Response Object

res:
  code: 200
  status: "200 OK"
  headers:
    content-type: application/json
  body: {...}  # Parsed JSON or raw string
  rawbody: "..." # Original response body

Operators

• Arithmetic: +, -, *, /, %
• Comparison: ==, !=, <, <=, >, >=
• Logical: &&, ||, !
• Ternary: condition ? true_value : false_value

Extending Probe

Probe supports custom actions through Protocol Buffers. Create your own actions to extend functionality beyond the built-in HTTP, SMTP, and Hello actions.

Configuration

Environment Variables

• Environment variables can be accessed by defining them in the root vars section

Defaults

Use YAML anchors for common configurations:

x_defaults: &api_defaults
  http:
    url: https://api.example.com
    headers:
      authorization: Bearer token

jobs:
- name: Test Job
  defaults: *api_defaults

Troubleshooting

Common Issues

Expression Evaluation Errors

• Check syntax: {{expression}} not {expression}
• Verify variable names and paths
• Use quotes around string values

HTTP Action Issues

• Verify URL format and accessibility
• Check headers and authentication
• Review timeout settings

Job Dependencies

• Ensure job IDs are unique
• Check needs references
• Avoid circular dependencies

Debug Output

Use --verbose flag for detailed execution information:

probe test.yml --verbose

Best Practices

1. Use descriptive names for workflows, jobs, and steps
2. Leverage outputs for data sharing between steps
3. Implement proper testing with meaningful assertions
4. Use defaults to reduce repetition
5. Structure workflows logically with clear dependencies
6. Handle errors gracefully with appropriate tests
7. Use variables for configuration management

FAQ

Common questions about Probe.

How is Probe different from Common Workflow Language (CWL) or Workflow Description Language (WDL)?

While CWL and WDL are powerful workflow languages designed for scientific computing and bioinformatics with complex data processing pipelines, Probe takes a different approach by specializing in web-based use cases.

Key Differences:

• Target Use Cases: CWL focuses on scientific data processing with Docker-based distributed execution, while WDL targets genomics pipelines with strong type systems and cloud-based distributed computing. Probe is designed specifically for API monitoring, test automation, and operational tasks.
• Internet Protocol Focus: Probe specializes in web use cases, providing built-in support for HTTP, SMTP, SSH, IMAP, and browser automation. This specialization allows you to define and execute workflows with minimal configuration for internet protocol-based tasks.
• Simplicity vs. Flexibility: While Probe offers less general-purpose flexibility compared to CWL or WDL, this is an intentional design choice. By focusing on web and internet protocols, Probe dramatically improves productivity in its target domain. The plugin-based architecture using Protocol Buffers still allows for extensibility when needed.
• Execution Model: Unlike CWL and WDL which are designed for distributed computing environments, Probe is optimized for lightweight, local execution with real-time monitoring capabilities.
• Syntax: Probe uses intuitive YAML-based configuration instead of the more complex type systems found in CWL and WDL, making it accessible to operations teams and developers working with web services.

Probe's value lies in providing the most efficient path for web-based automation tasks while maintaining the ability to extend functionality through custom actions when necessary. For more examples and advanced usage, check the examples directory.

Contributing

We welcome contributions! Please feel free to submit issues, feature requests, or pull requests.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Author

linyows