Establishing NICE Cognigy Bot Connection Tunnels via WebSocket API with Python

What You Will Build

• A production-grade Python module that opens, validates, and monitors a WebSocket tunnel to the NICE Cognigy bot runtime engine.
• The implementation uses the websockets library for tunnel transport and httpx for REST-based bot validation and token acquisition.
• The code is written in Python 3.9+ with full type hints, async/await patterns, and explicit error handling.

Prerequisites

• OAuth 2.0 Client Credentials flow configured in the Cognigy platform with scopes bot:read and runtime:execute
• Cognigy API v1 REST endpoints and wss://{tenant}.cognigy.com/runtime WebSocket endpoint
• Python 3.9 or higher
• External dependencies: pip install httpx websockets pydantic cryptography

Authentication Setup

Cognigy runtime tunnels require a valid bearer token embedded in the initial connection payload. The following code acquires a token using the Client Credentials grant and implements automatic retry for 429 Too Many Requests responses.

import time
import asyncio
import logging
from typing import Optional
import httpx

# Configure audit logger
logging.basicConfig(level=logging.INFO)
AUDIT_LOGGER = logging.getLogger("cognigy.tunnel.audit")
AUDIT_LOGGER.addHandler(logging.FileHandler("tunnel_audit.log"))

class CognigyAuthManager:
    def __init__(self, tenant: str, client_id: str, client_secret: str):
        self.tenant = tenant
        self.client_id = client_id
        self.client_secret = client_secret
        self.token_url = f"https://api.cognigy.com/oauth/token"
        self._token: Optional[str] = None
        self._expires_at: float = 0.0

    async def acquire_token(self) -> str:
        async with httpx.AsyncClient(timeout=10.0) as client:
            for attempt in range(3):
                try:
                    response = await client.post(
                        self.token_url,
                        data={
                            "grant_type": "client_credentials",
                            "client_id": self.client_id,
                            "client_secret": self.client_secret,
                            "scope": "bot:read runtime:execute"
                        }
                    )
                    response.raise_for_status()
                except httpx.HTTPStatusError as exc:
                    if exc.response.status_code == 429 and attempt < 2:
                        retry_after = int(exc.response.headers.get("Retry-After", 2))
                        AUDIT_LOGGER.warning("Rate limited during token acquisition. Retrying in %s seconds.", retry_after)
                        await asyncio.sleep(retry_after)
                        continue
                    raise RuntimeError(f"Token acquisition failed: {exc.response.status_code} {exc.response.text}") from exc

                payload = response.json()
                self._token = payload["access_token"]
                self._expires_at = time.time() + payload["expires_in"]
                AUDIT_LOGGER.info("OAuth token acquired successfully. Expires in %s seconds.", payload["expires_in"])
                return self._token

    def is_token_valid(self) -> bool:
        return self._token is not None and time.time() < (self._expires_at - 30)

Implementation

Step 1: Bot Engine Validation & Concurrent Connection Limits

Before initiating a WebSocket tunnel, the system must verify the bot status and check active session counts against a configured maximum to prevent resource exhaustion.

import pydantic
from pydantic import BaseModel, field_validator
import httpx

class BotValidationResult(BaseModel):
    bot_id: str
    is_active: bool
    channel_available: bool
    current_sessions: int
    max_allowed_sessions: int

class CognigyBotValidator:
    def __init__(self, tenant: str, auth_manager: CognigyAuthManager):
        self.tenant = tenant
        self.auth = auth_manager
        self.base_url = f"https://api.cognigy.com/api/v1"

    async def validate_bot_and_limits(self, bot_id: str, max_concurrent: int = 50) -> BotValidationResult:
        if not self.auth.is_token_valid():
            await self.auth.acquire_token()

        async with httpx.AsyncClient(timeout=10.0) as client:
            headers = {"Authorization": f"Bearer {self.auth._token}"}
            
            # Fetch bot configuration and active sessions
            bot_response = await client.get(f"{self.base_url}/bots/{bot_id}", headers=headers)
            sessions_response = await client.get(f"{self.base_url}/bots/{bot_id}/sessions", headers=headers)
            
            bot_response.raise_for_status()
            sessions_response.raise_for_status()

            bot_data = bot_response.json()
            sessions_data = sessions_response.json()
            active_count = len(sessions_data.get("items", []))

            result = BotValidationResult(
                bot_id=bot_id,
                is_active=bot_data.get("status") == "active",
                channel_available="webchat" in bot_data.get("channels", []),
                current_sessions=active_count,
                max_allowed_sessions=max_concurrent
            )

            if not result.is_active:
                raise RuntimeError(f"Bot {bot_id} is not active.")
            if not result.channel_available:
                raise RuntimeError(f"Bot {bot_id} does not support the requested channel.")
            if result.current_sessions >= result.max_allowed_sessions:
                raise RuntimeError(f"Bot {bot_id} has reached maximum concurrent session limit ({result.max_allowed_sessions}).")

            return result

Step 2: Connection Payload Construction & Schema Validation

The initial WebSocket message must conform to Cognigy runtime constraints. The following schema enforces required fields, protocol version directives, and token presence.

class ConnectPayload(BaseModel):
    type: str = "CONNECT"
    botId: str
    channel: str = "webchat"
    protocolVersion: str = "2.0"
    authToken: str
    metadata: dict = {}

    @field_validator("protocolVersion")
    @classmethod
    def validate_protocol(cls, v: str) -> str:
        allowed = ["1.0", "2.0", "2.1"]
        if v not in allowed:
            raise ValueError(f"Unsupported protocol version: {v}. Must be one of {allowed}")
        return v

    @field_validator("authToken")
    @classmethod
    def validate_token_format(cls, v: str) -> str:
        if not v.startswith("eyJ") or len(v) < 20:
            raise ValueError("Invalid auth token format provided.")
        return v

Step 3: Tunnel Initiation via Atomic CONNECT & Heartbeat Scheduling

The tunnel opens using an atomic CONNECT operation. Upon successful handshake, a background heartbeat scheduler maintains the connection and prevents idle timeouts.

import json
import websockets
import asyncio
from datetime import datetime, timezone

class CognigyTunnelEstablisher:
    def __init__(self, tenant: str, auth_manager: CognigyAuthManager, bot_validator: CognigyBotValidator):
        self.tenant = tenant
        self.auth = auth_manager
        self.validator = bot_validator
        self.ws_url = f"wss://{tenant}.cognigy.com/runtime"
        self.latency_ms: float = 0.0
        self.connection_start: float = 0.0
        self.callbacks: list = []
        self.heartbeat_task: Optional[asyncio.Task] = None
        self.is_connected: bool = False

    def on_event(self, callback):
        self.callbacks.append(callback)

    async def _emit_event(self, event_name: str, payload: dict):
        for cb in self.callbacks:
            try:
                await cb(event_name, payload)
            except Exception as e:
                AUDIT_LOGGER.error("Callback execution failed for %s: %s", event_name, e)

    async def _heartbeat_scheduler(self, ws: websockets.WebSocketClientProtocol):
        """Sends periodic pings to prevent idle timeout and tracks stability."""
        stability_checks = 0
        while self.is_connected:
            try:
                await asyncio.sleep(30)
                if not self.is_connected:
                    break
                ping_start = time.perf_counter()
                await ws.ping()
                await asyncio.sleep(2)  # Allow pong response
                ping_end = time.perf_counter()
                self.latency_ms = (ping_end - ping_start) * 1000
                stability_checks += 1
                AUDIT_LOGGER.info("Heartbeat %s completed. Latency: %.2f ms", stability_checks, self.latency_ms)
                await self._emit_event("heartbeat", {"latency_ms": self.latency_ms, "timestamp": datetime.now(timezone.utc).isoformat()})
            except websockets.ConnectionClosed as exc:
                AUDIT_LOGGER.warning("Heartbeat failed due to closed connection: %s", exc)
                self.is_connected = False
                break
            except Exception as exc:
                AUDIT_LOGGER.error("Heartbeat scheduler error: %s", exc)

    async def establish_tunnel(self, bot_id: str, max_concurrent: int = 50) -> websockets.WebSocketClientProtocol:
        # Step 1: Validate bot and limits
        validation = await self.validator.validate_bot_and_limits(bot_id, max_concurrent)
        AUDIT_LOGGER.info("Bot validation passed for %s. Active sessions: %s/%s", 
                          validation.bot_id, validation.current_sessions, validation.max_allowed_sessions)

        # Step 2: Ensure valid token
        if not self.auth.is_token_valid():
            await self.auth.acquire_token()

        # Step 3: Construct and validate payload
        payload = ConnectPayload(
            botId=bot_id,
            authToken=self.auth._token,
            protocolVersion="2.0"
        )
        payload_json = payload.model_dump_json()

        # Step 4: Open WebSocket and send atomic CONNECT
        self.connection_start = time.perf_counter()
        async with websockets.connect(self.ws_url, ping_interval=30, ping_timeout=10) as ws:
            await ws.send(payload_json)
            response = await ws.recv()
            handshake_latency = (time.perf_counter() - self.connection_start) * 1000
            self.latency_ms = handshake_latency

            response_data = json.loads(response)
            if response_data.get("type") != "CONNECTED":
                raise RuntimeError(f"Connection rejected by runtime: {response_data}")

            self.is_connected = True
            AUDIT_LOGGER.info("Tunnel established successfully. Latency: %.2f ms", self.latency_ms)
            await self._emit_event("tunnel_established", {
                "bot_id": bot_id,
                "latency_ms": self.latency_ms,
                "timestamp": datetime.now(timezone.utc).isoformat()
            })

            # Start heartbeat scheduler
            self.heartbeat_task = asyncio.create_task(self._heartbeat_scheduler(ws))
            return ws

Step 4: Connection Validation Logic & Channel Availability Verification

The tunnel establisher includes a validation pipeline that continuously checks token expiration and channel availability during runtime to prevent disconnection loops during scaling events.

    async def validate_runtime_connection(self, ws: websockets.WebSocketClientProtocol, bot_id: str) -> bool:
        """Verifies token validity and channel state without disrupting the tunnel."""
        if not self.auth.is_token_valid():
            AUDIT_LOGGER.warning("Runtime token expired during active tunnel. Refreshing.")
            await self.auth.acquire_token()
            
            # Re-authenticate over existing tunnel if supported, or signal reconnection
            refresh_payload = json.dumps({
                "type": "REFRESH_TOKEN",
                "botId": bot_id,
                "authToken": self.auth._token
            })
            await ws.send(refresh_payload)
            ack = await ws.recv()
            if json.loads(ack).get("type") != "TOKEN_REFRESHED":
                raise RuntimeError("Token refresh rejected by runtime.")
            
            await self._emit_event("token_refreshed", {"bot_id": bot_id})
            return True

        # Verify channel availability via a lightweight runtime probe
        probe = json.dumps({"type": "CHANNEL_PROBE", "botId": bot_id})
        await ws.send(probe)
        probe_response = await ws.recv()
        probe_data = json.loads(probe_response)

        if probe_data.get("status") != "available":
            raise RuntimeError(f"Channel unavailable for bot {bot_id}. Status: {probe_data.get('status')}")
        
        return True

Step 5: Deployment Pipeline Synchronization & Audit Logging

The establisher exposes callback registration for external CI/CD or deployment pipelines. All state transitions are written to the audit logger for infrastructure governance.

    async def close_tunnel(self, ws: websockets.WebSocketClientProtocol, bot_id: str):
        """Gracefully terminates the tunnel and emits final audit events."""
        self.is_connected = False
        if self.heartbeat_task:
            self.heartbeat_task.cancel()
            try:
                await self.heartbeat_task
            except asyncio.CancelledError:
                pass

        disconnect_payload = json.dumps({"type": "DISCONNECT", "botId": bot_id})
        try:
            await ws.send(disconnect_payload)
            await ws.close()
        except Exception as e:
            AUDIT_LOGGER.warning("Error during graceful tunnel closure: %s", e)

        AUDIT_LOGGER.info("Tunnel closed for bot %s. Total latency recorded: %.2f ms", bot_id, self.latency_ms)
        await self._emit_event("tunnel_closed", {
            "bot_id": bot_id,
            "final_latency_ms": self.latency_ms,
            "timestamp": datetime.now(timezone.utc).isoformat()
        })

Complete Working Example

The following script demonstrates end-to-end tunnel establishment, validation, and graceful shutdown. Replace the credential placeholders before execution.

import asyncio
import os

async def deployment_callback(event: str, payload: dict):
    """Example callback for external deployment pipeline synchronization."""
    print(f"[PIPELINE SYNC] Event: {event} | Payload: {payload}")
    AUDIT_LOGGER.info("Pipeline synchronized with event: %s", event)

async def main():
    tenant = os.getenv("COGNIGY_TENANT", "mytenant")
    client_id = os.getenv("COGNIGY_CLIENT_ID", "your_client_id")
    client_secret = os.getenv("COGNIGY_CLIENT_SECRET", "your_client_secret")
    target_bot_id = os.getenv("COGNIGY_BOT_ID", "bot_12345")

    auth_mgr = CognigyAuthManager(tenant, client_id, client_secret)
    bot_val = CognigyBotValidator(tenant, auth_mgr)
    establisher = CognigyTunnelEstablisher(tenant, auth_mgr, bot_val)
    
    establisher.on_event(deployment_callback)

    try:
        ws = await establisher.establish_tunnel(target_bot_id, max_concurrent=100)
        print("WebSocket tunnel established successfully.")
        
        # Perform runtime validation
        is_valid = await establisher.validate_runtime_connection(ws, target_bot_id)
        print(f"Runtime validation status: {is_valid}")

        # Simulate sustained connection
        print("Maintaining tunnel for 60 seconds...")
        await asyncio.sleep(60)

    except RuntimeError as e:
        AUDIT_LOGGER.error("Tunnel establishment failed: %s", e)
        print(f"Critical failure: {e}")
    except websockets.WebSocketException as e:
        AUDIT_LOGGER.error("WebSocket transport error: %s", e)
        print(f"Transport error: {e}")
    finally:
        if "ws" in locals():
            await establisher.close_tunnel(ws, target_bot_id)
            print("Tunnel closed and audited.")

if __name__ == "__main__":
    asyncio.run(main())

Common Errors & Debugging

Error: 401 Unauthorized

• Cause: The OAuth token is expired, malformed, or the client credentials are incorrect.
• Fix: Verify client_id and client_secret in the Cognigy developer console. Ensure the scope parameter includes runtime:execute. The CognigyAuthManager automatically refreshes tokens when is_token_valid() returns false.
• Code fix: The authentication setup block already implements automatic retry and expiration tracking. Ensure environment variables match the registered OAuth client.

Error: 403 Forbidden

• Cause: The OAuth client lacks the bot:read or runtime:execute scope, or the bot ID does not belong to the authenticated tenant.
• Fix: Update the OAuth client permissions in the Cognigy platform. Verify the bot_id matches the tenant namespace.
• Code fix: Add explicit scope validation in the acquire_token method if the platform returns scope-specific error payloads.

Error: 429 Too Many Requests

• Cause: Excessive token requests or session validation calls trigger rate limiting.
• Fix: Implement exponential backoff. The provided httpx retry loop reads the Retry-After header and sleeps accordingly.
• Code fix: The acquire_token method already includes a 3-attempt retry loop with Retry-After compliance.

Error: WebSocket 1006 Abnormal Closure

• Cause: The runtime engine dropped the connection due to idle timeout, invalid CONNECT payload, or network interruption.
• Fix: Ensure the heartbeat scheduler runs continuously. Verify the protocolVersion matches the runtime engine version. Check firewall rules for persistent WebSocket connections on port 443.
• Code fix: The _heartbeat_scheduler method sends pings every 30 seconds and tracks latency. If the connection drops, is_connected flips to false and the audit logger records the event.

Error: Pydantic ValidationError

• Cause: The ConnectPayload schema rejects invalid protocol versions or malformed tokens.
• Fix: Verify the protocolVersion is 2.0 or 2.1. Ensure the bearer token starts with eyJ and contains valid JWT segments.
• Code fix: The field_validator decorators explicitly check these constraints. Adjust the allowed list in validate_protocol if the runtime engine upgrades.

Official References

• NICE Cognigy API v1 Documentation
• Cognigy Runtime WebSocket Protocol
• Python websockets Library
• httpx Async Client Documentation
• Pydantic V2 Validation Reference