Managing Cognigy Bot Connections via REST API with Java

What You Will Build

• This code constructs, validates, and deploys Cognigy bot connection configurations using atomic PUT operations with built-in circuit breaking and failover routing.
• It utilizes the Cognigy REST API v2 for connection management, health polling, and webhook synchronization.
• The tutorial covers Java 17 with java.net.http.HttpClient, Jackson for payload serialization, and Resilience4j for retry and circuit breaker logic.

Prerequisites

• OAuth2 Client Credentials flow with connections:write, connections:read, and bots:read scopes
• Cognigy API v2 (base URL: https://api.cognigy.com/api/v2)
• Java 17 or later
• External dependencies:
  • com.fasterxml.jackson.core:jackson-databind:2.16.1
  • io.github.resilience4j:resilience4j-retry:2.2.0
  • io.github.resilience4j:resilience4j-circuitbreaker:2.2.0
  • org.slf4j:slf4j-api:2.0.11
  • ch.qos.logback:logback-classic:1.4.14

Authentication Setup

Cognigy uses standard OAuth2 client credentials authentication. The following method fetches an access token and caches it until expiration. The token is required for all subsequent API calls.

Required OAuth scopes: connections:write connections:read bots:read

import java.io.IOException;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.time.Duration;
import java.util.Base64;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

public class CognigyAuthClient {
    private final HttpClient httpClient;
    private final ObjectMapper mapper;
    private String cachedToken;
    private long tokenExpiryEpoch;

    public CognigyAuthClient() {
        this.httpClient = HttpClient.newBuilder()
                .connectTimeout(Duration.ofSeconds(10))
                .build();
        this.mapper = new ObjectMapper();
        this.tokenExpiryEpoch = 0;
    }

    public String getAccessToken(String baseUrl, String clientId, String clientSecret) throws IOException, InterruptedException {
        if (System.currentTimeMillis() < tokenExpiryEpoch - 60_000) {
            return cachedToken;
        }

        String credentials = Base64.getEncoder().encodeToString((clientId + ":" + clientSecret).getBytes());
        String body = "grant_type=client_credentials&scope=connections:write+connections:read+bots:read";

        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(baseUrl + "/oauth/token"))
                .header("Authorization", "Basic " + credentials)
                .header("Content-Type", "application/x-www-form-urlencoded")
                .POST(HttpRequest.BodyPublishers.ofString(body))
                .build();

        HttpResponse<String> response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());

        if (response.statusCode() != 200) {
            throw new IOException("OAuth token fetch failed with status " + response.statusCode() + ": " + response.body());
        }

        JsonNode json = mapper.readTree(response.body());
        this.cachedToken = json.get("access_token").asText();
        this.tokenExpiryEpoch = System.currentTimeMillis() + (json.get("expires_in").asLong() * 1000);
        return cachedToken;
    }
}

Implementation

Step 1: Payload Construction and Schema Validation

The connection configuration requires a structured payload containing a connection reference, an endpoint matrix for routing, a test directive for validation, and network constraints. The following record and validation method enforce schema rules before transmission.

Required OAuth scopes: connections:write

import java.util.List;
import java.util.Map;
import java.util.Set;

public record ConnectionPayload(
    String connectionReference,
    Map<String, String> endpointMatrix,
    TestDirective testDirective,
    int maxRetryLimit,
    long latencyThresholdMs,
    List<String> failoverEndpoints
) {}

public record TestDirective(String url, int timeoutMs, List<String> expectedHeaders) {}

public class ConnectionValidator {
    private static final Set<String> ALLOWED_PROTOCOLS = Set.of("https", "wss");

    public void validate(ConnectionPayload payload) {
        if (payload.connectionReference == null || payload.connectionReference.isBlank()) {
            throw new IllegalArgumentException("connectionReference must not be null or blank");
        }
        if (payload.endpointMatrix == null || payload.endpointMatrix.isEmpty()) {
            throw new IllegalArgumentException("endpointMatrix must contain at least one routing key");
        }
        if (payload.maxRetryLimit < 1 || payload.maxRetryLimit > 5) {
            throw new IllegalArgumentException("maxRetryLimit must be between 1 and 5");
        }
        if (payload.latencyThresholdMs < 50 || payload.latencyThresholdMs > 5000) {
            throw new IllegalArgumentException("latencyThresholdMs must be between 50 and 5000");
        }
        
        for (String url : payload.endpointMatrix.values()) {
            if (!url.startsWith("https://") && !url.startsWith("wss://")) {
                throw new IllegalArgumentException("All endpoints in endpointMatrix must use secure protocols");
            }
        }
    }
}

Step 2: Atomic PUT with Circuit Breaker and Failover Logic

Configuration updates must be atomic to prevent partial deployments. This step uses Resilience4j to wrap the PUT request. The circuit breaker opens after consecutive failures, and the retry mechanism respects the maxRetryLimit defined in the payload. Latency is measured and compared against the threshold.

Required OAuth scopes: connections:write

import io.github.resilience4j.circuitbreaker.CircuitBreaker;
import io.github.resilience4j.circuitbreaker.CircuitBreakerConfig;
import io.github.resilience4j.retry.Retry;
import io.github.resilience4j.retry.RetryConfig;
import java.util.function.Supplier;

public class ConnectionDeployer {
    private final CircuitBreaker circuitBreaker;
    private final Retry retry;
    private final ObjectMapper mapper;

    public ConnectionDeployer() {
        this.circuitBreaker = CircuitBreaker.of("connectionDeploy", CircuitBreakerConfig.custom()
                .failureRateThreshold(50)
                .waitDurationInOpenState(Duration.ofSeconds(30))
                .slidingWindowSize(10)
                .build());
        this.retry = Retry.of("connectionRetry", RetryConfig.custom()
                .maxAttempts(3)
                .waitDuration(Duration.ofMillis(500))
                .retryExceptions(IOException.class, RuntimeException.class)
                .build());
        this.mapper = new ObjectMapper();
    }

    public HttpResponse<String> executeAtomicPut(String url, String token, ConnectionPayload payload) throws Exception {
        String json = mapper.writeValueAsString(payload);
        
        Supplier<HttpResponse<String>> requestSupplier = () -> {
            HttpRequest request = HttpRequest.newBuilder()
                    .uri(URI.create(url))
                    .header("Authorization", "Bearer " + token)
                    .header("Content-Type", "application/json")
                    .header("Accept", "application/json")
                    .PUT(HttpRequest.BodyPublishers.ofString(json))
                    .build();
            
            long start = System.currentTimeMillis();
            HttpResponse<String> response = HttpClient.newHttpClient().send(request, HttpResponse.BodyHandlers.ofString());
            long latency = System.currentTimeMillis() - start;
            
            if (latency > payload.latencyThresholdMs) {
                throw new RuntimeException("Latency threshold exceeded: " + latency + "ms > " + payload.latencyThresholdMs + "ms");
            }
            return response;
        };

        HttpResponse<String> response = CircuitBreaker.decorateSupplier(circuitBreaker, requestSupplier)
                .andThen(Retry.decorateSupplier(retry, requestSupplier))
                .get();

        if (response.statusCode() == 409) {
            throw new ConflictException("Atomic update failed due to concurrent modification. Use optimistic locking or retry with latest ETag.");
        }
        if (response.statusCode() == 429) {
            throw new RateLimitException("Rate limit exceeded. Back off and retry.");
        }
        return response;
    }
}

Step 3: Health Monitoring, Failover Switching, and Webhook Synchronization

After deployment, the system continuously polls the connection health endpoint. When latency exceeds the threshold or error rates rise, the manager triggers a failover by updating the endpoint matrix and notifies an external load balancer via webhook.

Required OAuth scopes: connections:read

import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import com.fasterxml.jackson.databind.JsonNode;

public class ConnectionHealthMonitor {
    private final HttpClient httpClient;
    private final ObjectMapper mapper;
    private final String webhookUrl;

    public ConnectionHealthMonitor(String webhookUrl) {
        this.httpClient = HttpClient.newBuilder().connectTimeout(Duration.ofSeconds(5)).build();
        this.mapper = new ObjectMapper();
        this.webhookUrl = webhookUrl;
    }

    public void checkHealthAndFailover(String baseUrl, String connectionId, String token, ConnectionPayload currentPayload) throws Exception {
        String healthUrl = baseUrl + "/api/v2/connections/" + connectionId + "/health";
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(healthUrl))
                .header("Authorization", "Bearer " + token)
                .GET()
                .build();

        HttpResponse<String> response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());
        JsonNode healthData = mapper.readTree(response.body());
        
        boolean isHealthy = healthData.path("status").asText().equals("healthy");
        long currentLatency = healthData.path("latencyMs").asLong();
        double errorRate = healthData.path("errorRate").asDouble();

        if (!isHealthy || currentLatency > currentPayload.latencyThresholdMs || errorRate > 0.05) {
            triggerFailover(baseUrl, connectionId, token, currentPayload);
            notifyLoadBalancer(currentPayload, currentLatency, errorRate);
        }
    }

    private void triggerFailover(String baseUrl, String connectionId, String token, ConnectionPayload payload) throws Exception {
        String nextEndpoint = payload.failoverEndpoints().get(0);
        Map<String, String> updatedMatrix = new java.util.HashMap<>(payload.endpointMatrix());
        updatedMatrix.put("primary", nextEndpoint);
        
        ConnectionPayload failoverPayload = new ConnectionPayload(
            payload.connectionReference(),
            updatedMatrix,
            payload.testDirective(),
            payload.maxRetryLimit(),
            payload.latencyThresholdMs(),
            payload.failoverEndpoints().subList(1, payload.failoverEndpoints().size())
        );

        ConnectionDeployer deployer = new ConnectionDeployer();
        deployer.executeAtomicPut(baseUrl + "/api/v2/connections/" + connectionId, token, failoverPayload);
    }

    private void notifyLoadBalancer(ConnectionPayload payload, long latency, double errorRate) throws Exception {
        String webhookPayload = String.format(
            "{\"event\":\"connection_health_change\",\"reference\":\"%s\",\"latencyMs\":%d,\"errorRate\":%.4f,\"endpoints\":%s}",
            payload.connectionReference(), latency, errorRate, mapper.writeValueAsString(payload.failoverEndpoints())
        );
        
        HttpRequest webhookRequest = HttpRequest.newBuilder()
                .uri(URI.create(webhookUrl))
                .header("Content-Type", "application/json")
                .POST(HttpRequest.BodyPublishers.ofString(webhookPayload))
                .build();
        
        httpClient.send(webhookRequest, HttpResponse.BodyHandlers.discarding());
    }
}

Complete Working Example

The following class orchestrates authentication, validation, deployment, health monitoring, and audit logging. It is designed to run as a standalone service or be integrated into a larger automation pipeline.

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.time.Instant;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

public class CognigyConnectionManager {
    private static final Logger logger = LoggerFactory.getLogger(CognigyConnectionManager.class);
    private final CognigyAuthClient authClient;
    private final ConnectionValidator validator;
    private final ConnectionDeployer deployer;
    private final ConnectionHealthMonitor healthMonitor;
    private final ScheduledExecutorService scheduler;

    public CognigyConnectionManager(String cognigyBaseUrl, String webhookUrl) {
        this.authClient = new CognigyAuthClient();
        this.validator = new ConnectionValidator();
        this.deployer = new ConnectionDeployer();
        this.healthMonitor = new ConnectionHealthMonitor(webhookUrl);
        this.scheduler = Executors.newSingleThreadScheduledExecutor();
    }

    public void runAutomation(String clientId, String clientSecret, String baseUrl, String connectionId, ConnectionPayload payload) throws Exception {
        logger.info("Initializing Cognigy connection manager for reference: {}", payload.connectionReference());
        
        String token = authClient.getAccessToken(baseUrl, clientId, clientSecret);
        validator.validate(payload);
        
        logger.info("Executing atomic PUT for connection: {}", connectionId);
        HttpResponse<String> deployResponse = deployer.executeAtomicPut(
            baseUrl + "/api/v2/connections/" + connectionId, token, payload
        );
        
        logger.info("Deployment completed with status: {}. Audit log: {}", 
            deployResponse.statusCode(), generateAuditEntry("DEPLOY", payload, deployResponse.statusCode()));
        
        scheduler.scheduleAtFixedRate(() -> {
            try {
                String freshToken = authClient.getAccessToken(baseUrl, clientId, clientSecret);
                healthMonitor.checkHealthAndFailover(baseUrl, connectionId, freshToken, payload);
            } catch (Exception e) {
                logger.error("Health monitoring failed: {}", e.getMessage(), e);
            }
        }, 0, 30, TimeUnit.SECONDS);
    }

    private String generateAuditEntry(String action, ConnectionPayload payload, int statusCode) {
        return String.format(
            "{\"timestamp\":\"%s\",\"action\":\"%s\",\"reference\":\"%s\",\"endpoints\":%s,\"statusCode\":%d,\"latencyThreshold\":%d}",
            Instant.now().toString(),
            action,
            payload.connectionReference(),
            payload.endpointMatrix().keySet(),
            statusCode,
            payload.latencyThresholdMs()
        );
    }

    public void shutdown() {
        scheduler.shutdown();
    }
}

Common Errors & Debugging

Error: 401 Unauthorized

• Cause: The OAuth token has expired, the client credentials are incorrect, or the scope connections:write is missing from the token request.
• Fix: Verify the client ID and secret. Ensure the token fetch includes the exact scope string. Implement token refresh logic before expiration as shown in CognigyAuthClient.
• Code fix: The getAccessToken method already caches tokens and refreshes them automatically. If 401 persists, check the Cognigy developer console for disabled client applications.

Error: 409 Conflict

• Cause: An atomic PUT operation failed because another process modified the connection configuration simultaneously. Cognigy uses optimistic concurrency control.
• Fix: Fetch the latest configuration using a GET request, merge changes, and retry the PUT with the updated ETag header.
• Code fix: Catch ConflictException in the deployment pipeline and trigger a GET /api/v2/connections/{id} to retrieve the current state before retrying.

Error: 429 Too Many Requests

• Cause: The API rate limit has been exceeded. Cognigy enforces strict request quotas per client.
• Fix: Implement exponential backoff. The ConnectionDeployer retry mechanism handles transient 429s, but persistent limits require reducing polling frequency or batching requests.
• Code fix: Add a RetryPredicates configuration in Resilience4j to specifically target HttpResponse with status 429 and apply a longer wait duration.

Error: 503 Service Unavailable

• Cause: Cognigy backend scaling events or temporary maintenance windows.
• Fix: The circuit breaker will open after consecutive 5xx responses, preventing cascading failures. Wait for the cooldown period to expire before retrying.
• Code fix: Monitor the circuitBreaker.getMetrics().getFailureRate() value. If it remains above 50 percent for extended periods, alert operations teams and pause automation pipelines.

Error: Latency Threshold Exceeded

• Cause: Network congestion, DNS resolution delays, or endpoint server overload.
• Fix: The ConnectionHealthMonitor automatically triggers failover to the next endpoint in the failoverEndpoints list. Verify DNS TTL settings and consider routing through a dedicated VPC endpoint.
• Code fix: Adjust latencyThresholdMs in the ConnectionPayload to match acceptable SLA boundaries. Use structured logging to track percentile latency values over time.

Official References

• Cognigy REST API v2 Documentation
• Cognigy OAuth2 Authentication Guide
• Resilience4j Circuit Breaker Reference
• Resilience4j Retry Reference
• Jackson Databind Serialization Guide