# Temporal Workflow API Gateway - Usage Guide

## Overview

The API Gateway exposes **all Temporal operations** through a unified `/workflow` REST endpoint, eliminating the need to directly connect to Temporal ports (7233, 7234, 7235, 6933).

**Base URL**: `https://api.riotpiao.com/workflow`

---

## Unified REST API Design

### Request Format

All requests use a unified structure:

```json
{
  "action": "operation_name",
  "namespace": "default",
  "payload": {
    "specific": "fields_for_operation"
  }
}
```

### Response Format

All successful responses follow:

```json
{
  "success": true,
  "action": "operation_name",
  "namespace": "default",
  "data": {
    "operation_specific": "fields"
  },
  "timestamp": "2024-01-15T10:30:00Z"
}
```

### Error Response Format

```json
{
  "success": false,
  "action": "operation_name",
  "error": "error_code",
  "message": "Human readable error message",
  "details": {
    "additional": "context"
  },
  "timestamp": "2024-01-15T10:30:00Z"
}
```

---

## Operations Reference

### Workflow Execution Operations

#### 1. START_WORKFLOW

**Description**: Start a new workflow execution

**Request**:
```json
{
  "action": "START_WORKFLOW",
  "namespace": "default",
  "payload": {
    "workflow_id": "unique-workflow-id",
    "workflow_type": "OrderProcessing",
    "task_queue": "main_queue",
    "input": {
      "order_id": "12345",
      "amount": 99.99
    },
    "options": {
      "workflow_execution_timeout": 3600,
      "workflow_run_timeout": 1800,
      "workflow_task_timeout": 300
    },
    "memo": {
      "user_id": "user_123",
      "request_id": "req_456"
    }
  }
}
```

**Response**:
```json
{
  "success": true,
  "action": "START_WORKFLOW",
  "data": {
    "workflow_id": "unique-workflow-id",
    "run_id": "abc123def456",
    "start_time": "2024-01-15T10:30:00Z"
  }
}
```

**Status Codes**: 200 (Success), 400 (Invalid input), 409 (Duplicate workflow_id)

---

#### 2. DESCRIBE_WORKFLOW

**Description**: Get detailed information about a specific workflow execution

**Request**:
```json
{
  "action": "DESCRIBE_WORKFLOW",
  "namespace": "default",
  "payload": {
    "workflow_id": "unique-workflow-id",
    "run_id": "abc123def456"
  }
}
```

**Response**:
```json
{
  "success": true,
  "action": "DESCRIBE_WORKFLOW",
  "data": {
    "workflow_id": "unique-workflow-id",
    "run_id": "abc123def456",
    "workflow_type": "OrderProcessing",
    "status": "RUNNING",
    "start_time": "2024-01-15T10:30:00Z",
    "last_update_time": "2024-01-15T10:31:00Z",
    "execution_time": 60,
    "memo": {...},
    "search_attributes": {...},
    "pending_activities": 2
  }
}
```

---

#### 3. LIST_WORKFLOWS

**Description**: List workflow executions with optional filtering and pagination

**Request**:
```json
{
  "action": "LIST_WORKFLOWS",
  "namespace": "default",
  "payload": {
    "status": "RUNNING",
    "workflow_type": "OrderProcessing",
    "page_size": 50,
    "next_page_token": "token_from_previous_response",
    "filters": {
      "start_time_from": "2024-01-10T00:00:00Z",
      "start_time_to": "2024-01-20T23:59:59Z",
      "custom_attribute": "value"
    }
  }
}
```

**Status Filter Values**: `RUNNING`, `COMPLETED`, `FAILED`, `CANCELED`, `TERMINATED`, `CONTINUED_AS_NEW`

**Response**:
```json
{
  "success": true,
  "action": "LIST_WORKFLOWS",
  "data": {
    "executions": [
      {
        "workflow_id": "wf_001",
        "run_id": "run_001",
        "workflow_type": "OrderProcessing",
        "status": "RUNNING",
        "start_time": "2024-01-15T10:00:00Z"
      }
    ],
    "next_page_token": "token_for_next_page",
    "total_count": 150
  }
}
```

---

#### 4. GET_WORKFLOW_HISTORY

**Description**: Retrieve workflow execution history (events)

**Request**:
```json
{
  "action": "GET_WORKFLOW_HISTORY",
  "namespace": "default",
  "payload": {
    "workflow_id": "unique-workflow-id",
    "run_id": "abc123def456",
    "max_events": 100,
    "next_page_token": "token_from_previous"
  }
}
```

**Response**:
```json
{
  "success": true,
  "action": "GET_WORKFLOW_HISTORY",
  "data": {
    "events": [
      {
        "event_id": 1,
        "timestamp": "2024-01-15T10:30:00Z",
        "type": "WorkflowExecutionStarted",
        "attributes": {...}
      },
      {
        "event_id": 2,
        "timestamp": "2024-01-15T10:30:01Z",
        "type": "WorkflowTaskScheduled",
        "attributes": {...}
      }
    ],
    "next_page_token": "token_for_next_page"
  }
}
```

---

#### 5. TERMINATE_WORKFLOW

**Description**: Stop a running workflow execution immediately

**Request**:
```json
{
  "action": "TERMINATE_WORKFLOW",
  "namespace": "default",
  "payload": {
    "workflow_id": "unique-workflow-id",
    "run_id": "abc123def456",
    "reason": "Order cancelled by user",
    "details": {
      "cancelled_by": "user_123",
      "cancellation_code": "USER_REQUEST"
    }
  }
}
```

**Response**:
```json
{
  "success": true,
  "action": "TERMINATE_WORKFLOW",
  "data": {
    "workflow_id": "unique-workflow-id",
    "run_id": "abc123def456",
    "terminated_time": "2024-01-15T10:35:00Z"
  }
}
```

---

#### 6. CANCEL_WORKFLOW

**Description**: Request graceful cancellation of a workflow (allows cleanup)

**Request**:
```json
{
  "action": "CANCEL_WORKFLOW",
  "namespace": "default",
  "payload": {
    "workflow_id": "unique-workflow-id",
    "run_id": "abc123def456",
    "reason": "Cancel request"
  }
}
```

**Response**:
```json
{
  "success": true,
  "action": "CANCEL_WORKFLOW",
  "data": {
    "workflow_id": "unique-workflow-id",
    "status": "CANCELING"
  }
}
```

---

#### 7. SIGNAL_WORKFLOW

**Description**: Send a signal to a running workflow (trigger event handling)

**Request**:
```json
{
  "action": "SIGNAL_WORKFLOW",
  "namespace": "default",
  "payload": {
    "workflow_id": "unique-workflow-id",
    "run_id": "abc123def456",
    "signal_name": "payment_received",
    "input": {
      "payment_id": "pay_123",
      "amount": 99.99
    }
  }
}
```

**Response**:
```json
{
  "success": true,
  "action": "SIGNAL_WORKFLOW",
  "data": {
    "workflow_id": "unique-workflow-id",
    "signal_name": "payment_received",
    "signaled_time": "2024-01-15T10:32:00Z"
  }
}
```

---

#### 8. QUERY_WORKFLOW

**Description**: Query workflow state without modifying it (read-only)

**Request**:
```json
{
  "action": "QUERY_WORKFLOW",
  "namespace": "default",
  "payload": {
    "workflow_id": "unique-workflow-id",
    "run_id": "abc123def456",
    "query_type": "get_order_status",
    "args": {
      "include_history": false
    }
  }
}
```

**Response**:
```json
{
  "success": true,
  "action": "QUERY_WORKFLOW",
  "data": {
    "query_result": {
      "order_status": "payment_pending",
      "current_activity": "WaitForPayment",
      "started_at": "2024-01-15T10:30:00Z"
    }
  }
}
```

---

#### 9. RESET_WORKFLOW

**Description**: Reset workflow to a specific point in history

**Request**:
```json
{
  "action": "RESET_WORKFLOW",
  "namespace": "default",
  "payload": {
    "workflow_id": "unique-workflow-id",
    "run_id": "abc123def456",
    "reset_type": "FIRST_DECISION_COMPLETED",
    "event_id": 5
  }
}
```

**Reset Types**: `FIRST_DECISION_COMPLETED`, `LAST_DECISION_COMPLETED`, `LAST_CONTINUOUS_DECISION_STARTED`, `BAD_BINARY_ID`

---

#### 10. UPDATE_WORKFLOW

**Description**: Update a running workflow (async operation)

**Request**:
```json
{
  "action": "UPDATE_WORKFLOW",
  "namespace": "default",
  "payload": {
    "workflow_id": "unique-workflow-id",
    "run_id": "abc123def456",
    "update_name": "pause_workflow",
    "input": {
      "reason": "maintenance"
    }
  }
}
```

---

### Activity Operations

#### 11. HEARTBEAT_ACTIVITY

**Description**: Record activity heartbeat to indicate progress

**Request**:
```json
{
  "action": "HEARTBEAT_ACTIVITY",
  "namespace": "default",
  "payload": {
    "task_token": "base64_encoded_token",
    "details": {
      "processed_items": 100,
      "total_items": 500,
      "percentage": 20
    }
  }
}
```

---

#### 12. COMPLETE_ACTIVITY

**Description**: Mark an activity task as completed with result

**Request**:
```json
{
  "action": "COMPLETE_ACTIVITY",
  "namespace": "default",
  "payload": {
    "task_token": "base64_encoded_token",
    "result": {
      "status": "success",
      "output_data": {...}
    }
  }
}
```

---

#### 13. FAIL_ACTIVITY

**Description**: Mark an activity task as failed with error details

**Request**:
```json
{
  "action": "FAIL_ACTIVITY",
  "namespace": "default",
  "payload": {
    "task_token": "base64_encoded_token",
    "failure": {
      "type": "ApplicationError",
      "message": "Database connection timeout",
      "retry": true
    }
  }
}
```

---

### Namespace Operations

#### 14. LIST_NAMESPACES

**Description**: List all available namespaces

**Request**:
```json
{
  "action": "LIST_NAMESPACES",
  "payload": {
    "page_size": 50,
    "next_page_token": "token"
  }
}
```

**Response**:
```json
{
  "success": true,
  "action": "LIST_NAMESPACES",
  "data": {
    "namespaces": [
      {
        "name": "default",
        "description": "Default namespace",
        "owner_email": "admin@example.com",
        "state": "ACTIVE",
        "created_time": "2023-01-01T00:00:00Z"
      }
    ]
  }
}
```

---

#### 15. DESCRIBE_NAMESPACE

**Description**: Get details about a specific namespace

**Request**:
```json
{
  "action": "DESCRIBE_NAMESPACE",
  "namespace": "default",
  "payload": {}
}
```

---

#### 16. CREATE_NAMESPACE

**Description**: Create a new namespace

**Request**:
```json
{
  "action": "CREATE_NAMESPACE",
  "payload": {
    "namespace_name": "production",
    "description": "Production workflows",
    "owner_email": "devops@example.com",
    "retention_days": 30,
    "data": {
      "team": "backend",
      "environment": "prod"
    }
  }
}
```

---

#### 17. UPDATE_NAMESPACE

**Description**: Update namespace configuration

**Request**:
```json
{
  "action": "UPDATE_NAMESPACE",
  "namespace": "default",
  "payload": {
    "description": "Updated description",
    "retention_days": 45,
    "data": {
      "team": "backend"
    }
  }
}
```

---

#### 18. DELETE_NAMESPACE

**Description**: Delete a namespace (irreversible)

**Request**:
```json
{
  "action": "DELETE_NAMESPACE",
  "namespace": "default",
  "payload": {
    "reason": "Cleanup old namespace"
  }
}
```

---

### Search Attributes Operations

#### 19. LIST_SEARCH_ATTRIBUTES

**Description**: List custom search attributes for a namespace

**Request**:
```json
{
  "action": "LIST_SEARCH_ATTRIBUTES",
  "namespace": "default",
  "payload": {}
}
```

**Response**:
```json
{
  "success": true,
  "action": "LIST_SEARCH_ATTRIBUTES",
  "data": {
    "attributes": {
      "order_id": "Keyword",
      "customer_tier": "Keyword",
      "total_amount": "Double",
      "created_date": "Datetime"
    }
  }
}
```

---

#### 20. ADD_SEARCH_ATTRIBUTES

**Description**: Add custom search attributes to a namespace

**Request**:
```json
{
  "action": "ADD_SEARCH_ATTRIBUTES",
  "namespace": "default",
  "payload": {
    "search_attributes": {
      "shipping_address": "Text",
      "priority_level": "Int",
      "estimated_delivery": "Datetime"
    }
  }
}
```

---

### Cluster Operations

#### 21. GET_CLUSTER_INFO

**Description**: Get cluster information and status

**Request**:
```json
{
  "action": "GET_CLUSTER_INFO",
  "payload": {}
}
```

**Response**:
```json
{
  "success": true,
  "action": "GET_CLUSTER_INFO",
  "data": {
    "cluster_name": "temporal-cluster",
    "version": "1.24.0",
    "members": [
      {
        "role": "leader",
        "address": "temporal-0:7233"
      },
      {
        "role": "member",
        "address": "temporal-1:7233"
      }
    ]
  }
}
```

---

#### 22. LIST_CLUSTER_MEMBERS

**Description**: List all cluster members

**Request**:
```json
{
  "action": "LIST_CLUSTER_MEMBERS",
  "payload": {}
}
```

---

#### 23. GET_SYSTEM_INFO

**Description**: Get system information and metrics

**Request**:
```json
{
  "action": "GET_SYSTEM_INFO",
  "payload": {}
}
```

**Response**:
```json
{
  "success": true,
  "action": "GET_SYSTEM_INFO",
  "data": {
    "server_version": "1.24.0",
    "capabilities": [
      "SIGNAL_WORKFLOW",
      "QUERY_WORKFLOW",
      "UPDATE_WORKFLOW"
    ],
    "uptime_seconds": 864000
  }
}
```

---

### Metrics Endpoint

#### 24. GET_METRICS

**Description**: Get Prometheus metrics

**Request**:
```json
{
  "action": "GET_METRICS",
  "payload": {
    "format": "prometheus",
    "filter": "temporal_"
  }
}
```

**Or via direct HTTP**:
```bash
GET https://api.riotpiao.com/workflow/metrics
```

**Response**: Prometheus text format metrics

**Key Metrics**:
- `temporal_workflow_execution_started_total` - Total workflows started
- `temporal_workflow_execution_completed_total` - Workflows completed
- `temporal_workflow_execution_failed_total` - Workflows failed
- `temporal_activity_execution_started_total` - Activities started
- `temporal_activity_execution_completed_total` - Activities completed
- `temporal_activity_execution_failed_total` - Activities failed
- `temporal_request_latency_histogram` - Request latencies

---

## HTTP Endpoints

### POST /workflow

Execute Temporal operations with JSON request body (all operations above)

```bash
curl -X POST https://api.riotpiao.com/workflow \
  -H 'Content-Type: application/json' \
  -d '{
    "action": "START_WORKFLOW",
    "namespace": "default",
    "payload": {...}
  }'
```

---

### GET /workflow/metrics

Get Prometheus metrics directly

```bash
curl https://api.riotpiao.com/workflow/metrics
```

---

### GET /workflow/health

Health check endpoint

```bash
curl https://api.riotpiao.com/workflow/health
```

**Response**:
```json
{
  "status": "healthy",
  "temporal_connected": true,
  "latency_ms": 5
}
```

---

## Error Codes

| Code | HTTP | Meaning |
|------|------|---------|
| `INVALID_REQUEST` | 400 | Missing or invalid fields |
| `INVALID_ACTION` | 400 | Unknown action |
| `AUTHENTICATION_FAILED` | 401 | Auth header missing/invalid |
| `PERMISSION_DENIED` | 403 | No permission for action |
| `NAMESPACE_NOT_FOUND` | 404 | Namespace doesn't exist |
| `WORKFLOW_NOT_FOUND` | 404 | Workflow doesn't exist |
| `WORKFLOW_ALREADY_EXISTS` | 409 | Workflow ID duplicate |
| `WORKFLOW_EXECUTING` | 409 | Workflow still running |
| `TEMPORAL_UNAVAILABLE` | 503 | Temporal server unreachable |
| `INTERNAL_ERROR` | 500 | Unexpected server error |

---

## Task Queue Management

### What is a Task Queue?

A **Task Queue** is a queue where:
- **Workflow Tasks** are dispatched to workflow workers
- **Activity Tasks** are dispatched to activity workers
- Multiple workers can listen on the same queue
- Load is distributed among available workers

### Task Queue Attributes

```json
{
  "name": "main_queue",
  "kind": "WORKFLOW",  // or ACTIVITY
  "poison_pill_count": 0,
  "reader_count": 3,
  "ack_level": 1050
}
```

---

## TaskQueue Recommendation & Analysis

### Option 1: Expose TaskQueue as Managed Resource (RECOMMENDED)

**Design**: Allow CRUD operations on task queues via `/workflow` endpoint with new operations:

```json
{
  "action": "LIST_TASK_QUEUES",
  "payload": {
    "namespace": "default",
    "queue_type": "WORKFLOW"  // or ACTIVITY
  }
}
```

**Pros**:
✅ **Visibility** - Know all active queues and their status
✅ **Monitoring** - Track reader count, poison pills, ack level
✅ **Debugging** - Identify stuck queues or low reader count
✅ **Consistent UI** - All operations through same `/workflow` endpoint
✅ **Alerting** - Monitor queue health metrics

**Cons**:
❌ **Limited Utility** - Can't modify task queue behavior (read-only mostly)
❌ **Not Needed for Normal Operations** - Workers create/manage queues automatically
❌ **Complex State** - Queue state changes automatically with worker connections

---

### Option 2: Hidden Implementation Detail (NOT RECOMMENDED)

**Design**: Don't expose TaskQueue operations; let workers manage queues

**Pros**:
✅ **Simpler API** - Fewer operations
✅ **Fewer Bugs** - Less user confusion
✅ **Less Operational Burden** - Workers handle it

**Cons**:
❌ **No Visibility** - Can't see queue status
❌ **Harder Debugging** - No way to verify queue health
❌ **No Alerting** - Can't monitor queue metrics
❌ **Production Risk** - Silent failures if queues stuck

---

### **RECOMMENDATION: Option 1 (Expose as Read-Only Monitor)**

**Implementation**:

```json
{
  "action": "LIST_TASK_QUEUES",
  "namespace": "default",
  "payload": {
    "queue_type": "WORKFLOW"
  }
}
```

Response:
```json
{
  "success": true,
  "data": {
    "queues": [
      {
        "name": "main_queue",
        "type": "WORKFLOW",
        "reader_count": 3,
        "poison_pill_count": 0,
        "last_activity": "2024-01-15T10:32:00Z"
      }
    ]
  }
}
```

**Benefits**:
- Operational visibility without complication
- Enables monitoring dashboards
- Helps debug worker connectivity issues
- No direct manipulation (workers manage lifecycle)
- Completes the REST API for all Temporal concepts

---

## Usage Examples

### Example 1: Start a Workflow and Monitor

```bash
# Start workflow
curl -X POST https://api.riotpiao.com/workflow \
  -H 'Content-Type: application/json' \
  -d '{
    "action": "START_WORKFLOW",
    "namespace": "default",
    "payload": {
      "workflow_id": "order-123",
      "workflow_type": "ProcessOrder",
      "task_queue": "orders_queue",
      "input": {"order_id": "123", "amount": 99.99}
    }
  }'

# Check workflow status
curl -X POST https://api.riotpiao.com/workflow \
  -d '{
    "action": "DESCRIBE_WORKFLOW",
    "namespace": "default",
    "payload": {
      "workflow_id": "order-123",
      "run_id": "run_abc123"
    }
  }'
```

### Example 2: Send Signal to Running Workflow

```bash
curl -X POST https://api.riotpiao.com/workflow \
  -H 'Content-Type: application/json' \
  -d '{
    "action": "SIGNAL_WORKFLOW",
    "namespace": "default",
    "payload": {
      "workflow_id": "order-123",
      "run_id": "run_abc123",
      "signal_name": "payment_completed",
      "input": {"amount": 99.99, "payment_id": "pay_456"}
    }
  }'
```

### Example 3: Query Workflow State

```bash
curl -X POST https://api.riotpiao.com/workflow \
  -d '{
    "action": "QUERY_WORKFLOW",
    "namespace": "default",
    "payload": {
      "workflow_id": "order-123",
      "run_id": "run_abc123",
      "query_type": "get_status"
    }
  }'
```

### Example 4: List Running Workflows

```bash
curl -X POST https://api.riotpiao.com/workflow \
  -d '{
    "action": "LIST_WORKFLOWS",
    "namespace": "default",
    "payload": {
      "status": "RUNNING",
      "page_size": 50
    }
  }'
```

### Example 5: Monitor Task Queues

```bash
curl -X POST https://api.riotpiao.com/workflow \
  -d '{
    "action": "LIST_TASK_QUEUES",
    "namespace": "default",
    "payload": {
      "queue_type": "WORKFLOW"
    }
  }'
```

---

## Authentication & Security

**Planned for Phase 3**:
- Bearer token authentication
- Namespace-based authorization
- Action-based permissions (e.g., can only QUERY, not TERMINATE)
- Audit logging

---

## Rate Limiting

**Planned for Phase 4**:
- Per-namespace rate limits
- Per-action rate limits
- Backoff/retry guidance

---

## Pagination

For list operations supporting pagination:

```json
{
  "action": "LIST_WORKFLOWS",
  "payload": {
    "page_size": 50,
    "next_page_token": "token_from_previous_response"
  }
}
```

Response includes `next_page_token` for fetching next page:

```json
{
  "data": {
    "executions": [...],
    "next_page_token": "token_for_next_page"
  }
}
```

---

## Filtering Syntax

For advanced filtering in LIST operations:

**Time-based**:
- `start_time_from`: ISO 8601 datetime
- `start_time_to`: ISO 8601 datetime

**Status**:
- `status`: RUNNING, COMPLETED, FAILED, CANCELED, TERMINATED, CONTINUED_AS_NEW

**Type**:
- `workflow_type`: Workflow type name

**Custom Attributes**:
- Custom indexed attributes: `"custom_field": "value"`

---

## Timeout Configuration

For long-running operations:

```json
{
  "action": "START_WORKFLOW",
  "payload": {
    "workflow_id": "long_running",
    "workflow_type": "LongTask",
    "task_queue": "long_queue",
    "options": {
      "workflow_execution_timeout": 86400,  // 24 hours
      "workflow_run_timeout": 3600,          // 1 hour per run
      "workflow_task_timeout": 300           // 5 minutes per task
    }
  }
}
```

---

## Support & Debugging

### Check Health
```bash
curl https://api.riotpiao.com/workflow/health
```

### View Cluster Info
```bash
curl -X POST https://api.riotpiao.com/workflow \
  -d '{"action": "GET_CLUSTER_INFO", "payload": {}}'
```

### Monitor Metrics
```bash
curl https://api.riotpiao.com/workflow/metrics | grep temporal_workflow
```

### Check Namespace Status
```bash
curl -X POST https://api.riotpiao.com/workflow \
  -d '{
    "action": "DESCRIBE_NAMESPACE",
    "namespace": "default"
  }'
```

---

## What Changed from Direct Temporal Access

| Operation | Before (Direct gRPC) | After (REST) |
|-----------|----------------------|--------------|
| Start Workflow | `client.StartWorkflowExecution()` | `POST /workflow` with `START_WORKFLOW` action |
| List Workflows | `client.ListWorkflowExecutions()` | `POST /workflow` with `LIST_WORKFLOWS` action |
| Signal Workflow | `client.SignalWorkflowExecution()` | `POST /workflow` with `SIGNAL_WORKFLOW` action |
| Query Workflow | `client.QueryWorkflowExecution()` | `POST /workflow` with `QUERY_WORKFLOW` action |
| Access Metrics | `curl localhost:6933/metrics` | `curl https://api.riotpiao.com/workflow/metrics` |

**Benefits**:
- Single endpoint for all operations
- No port forwarding needed
- Unified authentication/authorization
- Easier monitoring and logging
- RESTful consistency

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## Next Steps

1. **Implement** gateway integration with Temporal Go SDK
2. **Add** gRPC tunneling through HTTP/2
3. **Deploy** `/workflow` endpoint
4. **Monitor** operations and latencies
5. **Extend** with Phase 3 authentication
6. **Add** Phase 4 rate limiting

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**Ready to implement?** See implementation guide: `TEMPORAL_IMPLEMENTATION.md`