📡 Event-Driven Architecture with TuskLang Java

"We don't bow to any king" - Event Edition

TuskLang Java enables sophisticated event-driven architectures with built-in support for event sourcing, CQRS, message queues, and real-time event processing. Build reactive systems that respond to events and maintain data consistency across distributed services.

🎯 Event-Driven Architecture Overview

Event Sourcing Configuration

import org.tusklang.java.TuskLang;
import org.tusklang.java.config.TuskConfig;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class EventDrivenApplication {
    
    @Bean
    public TuskConfig tuskConfig() {
        TuskLang parser = new TuskLang();
        return parser.parseFile("event-driven.tsk", TuskConfig.class);
    }
    
    public static void main(String[] args) {
        SpringApplication.run(EventDrivenApplication.class, args);
    }
}
// Event-driven configuration
@TuskConfig
public class EventDrivenConfig {
    private String applicationName;
    private String version;
    private EventStoreConfig eventStore;
    private MessageQueueConfig messageQueue;
    private EventHandlersConfig eventHandlers;
    private ProjectionConfig projections;
    private CqrsConfig cqrs;
    private MonitoringConfig monitoring;
    
    // Getters and setters
    public String getApplicationName() { return applicationName; }
    public void setApplicationName(String applicationName) { this.applicationName = applicationName; }
    
    public String getVersion() { return version; }
    public void setVersion(String version) { this.version = version; }
    
    public EventStoreConfig getEventStore() { return eventStore; }
    public void setEventStore(EventStoreConfig eventStore) { this.eventStore = eventStore; }
    
    public MessageQueueConfig getMessageQueue() { return messageQueue; }
    public void setMessageQueue(MessageQueueConfig messageQueue) { this.messageQueue = messageQueue; }
    
    public EventHandlersConfig getEventHandlers() { return eventHandlers; }
    public void setEventHandlers(EventHandlersConfig eventHandlers) { this.eventHandlers = eventHandlers; }
    
    public ProjectionConfig getProjections() { return projections; }
    public void setProjections(ProjectionConfig projections) { this.projections = projections; }
    
    public CqrsConfig getCqrs() { return cqrs; }
    public void setCqrs(CqrsConfig cqrs) { this.cqrs = cqrs; }
    
    public MonitoringConfig getMonitoring() { return monitoring; }
    public void setMonitoring(MonitoringConfig monitoring) { this.monitoring = monitoring; }
}
@TuskConfig
public class EventStoreConfig {
    private String type;
    private String connectionString;
    private String database;
    private String collection;
    private SnapshotConfig snapshot;
    private SerializationConfig serialization;
    
    // Getters and setters
    public String getType() { return type; }
    public void setType(String type) { this.type = type; }
    
    public String getConnectionString() { return connectionString; }
    public void setConnectionString(String connectionString) { this.connectionString = connectionString; }
    
    public String getDatabase() { return database; }
    public void setDatabase(String database) { this.database = database; }
    
    public String getCollection() { return collection; }
    public void setCollection(String collection) { this.collection = collection; }
    
    public SnapshotConfig getSnapshot() { return snapshot; }
    public void setSnapshot(SnapshotConfig snapshot) { this.snapshot = snapshot; }
    
    public SerializationConfig getSerialization() { return serialization; }
    public void setSerialization(SerializationConfig serialization) { this.serialization = serialization; }
}
@TuskConfig
public class SnapshotConfig {
    private boolean enabled;
    private int interval;
    private String storage;
    private CompressionConfig compression;
    
    // Getters and setters
    public boolean isEnabled() { return enabled; }
    public void setEnabled(boolean enabled) { this.enabled = enabled; }
    
    public int getInterval() { return interval; }
    public void setInterval(int interval) { this.interval = interval; }
    
    public String getStorage() { return storage; }
    public void setStorage(String storage) { this.storage = storage; }
    
    public CompressionConfig getCompression() { return compression; }
    public void setCompression(CompressionConfig compression) { this.compression = compression; }
}
@TuskConfig
public class CompressionConfig {
    private boolean enabled;
    private String algorithm;
    private int level;
    
    // Getters and setters
    public boolean isEnabled() { return enabled; }
    public void setEnabled(boolean enabled) { this.enabled = enabled; }
    
    public String getAlgorithm() { return algorithm; }
    public void setAlgorithm(String algorithm) { this.algorithm = algorithm; }
    
    public int getLevel() { return level; }
    public void setLevel(int level) { this.level = level; }
}
@TuskConfig
public class SerializationConfig {
    private String format;
    private String schemaRegistry;
    private boolean schemaValidation;
    private Map<String, String> customSerializers;
    
    // Getters and setters
    public String getFormat() { return format; }
    public void setFormat(String format) { this.format = format; }
    
    public String getSchemaRegistry() { return schemaRegistry; }
    public void setSchemaRegistry(String schemaRegistry) { this.schemaRegistry = schemaRegistry; }
    
    public boolean isSchemaValidation() { return schemaValidation; }
    public void setSchemaValidation(boolean schemaValidation) { this.schemaValidation = schemaValidation; }
    
    public Map<String, String> getCustomSerializers() { return customSerializers; }
    public void setCustomSerializers(Map<String, String> customSerializers) { this.customSerializers = customSerializers; }
}
@TuskConfig
public class MessageQueueConfig {
    private String broker;
    private List<String> brokers;
    private String topic;
    private String groupId;
    private int partitions;
    private int replicationFactor;
    private RetentionConfig retention;
    private ConsumerConfig consumer;
    private ProducerConfig producer;
    
    // Getters and setters
    public String getBroker() { return broker; }
    public void setBroker(String broker) { this.broker = broker; }
    
    public List<String> getBrokers() { return brokers; }
    public void setBrokers(List<String> brokers) { this.brokers = brokers; }
    
    public String getTopic() { return topic; }
    public void setTopic(String topic) { this.topic = topic; }
    
    public String getGroupId() { return groupId; }
    public void setGroupId(String groupId) { this.groupId = groupId; }
    
    public int getPartitions() { return partitions; }
    public void setPartitions(int partitions) { this.partitions = partitions; }
    
    public int getReplicationFactor() { return replicationFactor; }
    public void setReplicationFactor(int replicationFactor) { this.replicationFactor = replicationFactor; }
    
    public RetentionConfig getRetention() { return retention; }
    public void setRetention(RetentionConfig retention) { this.retention = retention; }
    
    public ConsumerConfig getConsumer() { return consumer; }
    public void setConsumer(ConsumerConfig consumer) { this.consumer = consumer; }
    
    public ProducerConfig getProducer() { return producer; }
    public void setProducer(ProducerConfig producer) { this.producer = producer; }
}
@TuskConfig
public class RetentionConfig {
    private long timeMs;
    private long sizeBytes;
    private String cleanupPolicy;
    
    // Getters and setters
    public long getTimeMs() { return timeMs; }
    public void setTimeMs(long timeMs) { this.timeMs = timeMs; }
    
    public long getSizeBytes() { return sizeBytes; }
    public void setSizeBytes(long sizeBytes) { this.sizeBytes = sizeBytes; }
    
    public String getCleanupPolicy() { return cleanupPolicy; }
    public void setCleanupPolicy(String cleanupPolicy) { this.cleanupPolicy = cleanupPolicy; }
}
@TuskConfig
public class ConsumerConfig {
    private String autoOffsetReset;
    private int maxPollRecords;
    private int maxPollInterval;
    private int sessionTimeout;
    private int heartbeatInterval;
    private boolean enableAutoCommit;
    private int autoCommitInterval;
    
    // Getters and setters
    public String getAutoOffsetReset() { return autoOffsetReset; }
    public void setAutoOffsetReset(String autoOffsetReset) { this.autoOffsetReset = autoOffsetReset; }
    
    public int getMaxPollRecords() { return maxPollRecords; }
    public void setMaxPollRecords(int maxPollRecords) { this.maxPollRecords = maxPollRecords; }
    
    public int getMaxPollInterval() { return maxPollInterval; }
    public void setMaxPollInterval(int maxPollInterval) { this.maxPollInterval = maxPollInterval; }
    
    public int getSessionTimeout() { return sessionTimeout; }
    public void setSessionTimeout(int sessionTimeout) { this.sessionTimeout = sessionTimeout; }
    
    public int getHeartbeatInterval() { return heartbeatInterval; }
    public void setHeartbeatInterval(int heartbeatInterval) { this.heartbeatInterval = heartbeatInterval; }
    
    public boolean isEnableAutoCommit() { return enableAutoCommit; }
    public void setEnableAutoCommit(boolean enableAutoCommit) { this.enableAutoCommit = enableAutoCommit; }
    
    public int getAutoCommitInterval() { return autoCommitInterval; }
    public void setAutoCommitInterval(int autoCommitInterval) { this.autoCommitInterval = autoCommitInterval; }
}
@TuskConfig
public class ProducerConfig {
    private String acks;
    private int retries;
    private int batchSize;
    private int lingerMs;
    private int bufferMemory;
    private String compressionType;
    
    // Getters and setters
    public String getAcks() { return acks; }
    public void setAcks(String acks) { this.acks = acks; }
    
    public int getRetries() { return retries; }
    public void setRetries(int retries) { this.retries = retries; }
    
    public int getBatchSize() { return batchSize; }
    public void setBatchSize(int batchSize) { this.batchSize = batchSize; }
    
    public int getLingerMs() { return lingerMs; }
    public void setLingerMs(int lingerMs) { this.lingerMs = lingerMs; }
    
    public int getBufferMemory() { return bufferMemory; }
    public void setBufferMemory(int bufferMemory) { this.bufferMemory = bufferMemory; }
    
    public String getCompressionType() { return compressionType; }
    public void setCompressionType(String compressionType) { this.compressionType = compressionType; }
}
@TuskConfig
public class EventHandlersConfig {
    private Map<String, String> handlers;
    private ThreadPoolConfig threadPool;
    private RetryConfig retry;
    private DeadLetterConfig deadLetter;
    
    // Getters and setters
    public Map<String, String> getHandlers() { return handlers; }
    public void setHandlers(Map<String, String> handlers) { this.handlers = handlers; }
    
    public ThreadPoolConfig getThreadPool() { return threadPool; }
    public void setThreadPool(ThreadPoolConfig threadPool) { this.threadPool = threadPool; }
    
    public RetryConfig getRetry() { return retry; }
    public void setRetry(RetryConfig retry) { this.retry = retry; }
    
    public DeadLetterConfig getDeadLetter() { return deadLetter; }
    public void setDeadLetter(DeadLetterConfig deadLetter) { this.deadLetter = deadLetter; }
}
@TuskConfig
public class ThreadPoolConfig {
    private int coreSize;
    private int maxSize;
    private int queueCapacity;
    private int keepAliveSeconds;
    private String threadNamePrefix;
    
    // Getters and setters
    public int getCoreSize() { return coreSize; }
    public void setCoreSize(int coreSize) { this.coreSize = coreSize; }
    
    public int getMaxSize() { return maxSize; }
    public void setMaxSize(int maxSize) { this.maxSize = maxSize; }
    
    public int getQueueCapacity() { return queueCapacity; }
    public void setQueueCapacity(int queueCapacity) { this.queueCapacity = queueCapacity; }
    
    public int getKeepAliveSeconds() { return keepAliveSeconds; }
    public void setKeepAliveSeconds(int keepAliveSeconds) { this.keepAliveSeconds = keepAliveSeconds; }
    
    public String getThreadNamePrefix() { return threadNamePrefix; }
    public void setThreadNamePrefix(String threadNamePrefix) { this.threadNamePrefix = threadNamePrefix; }
}
@TuskConfig
public class RetryConfig {
    private int maxAttempts;
    private long initialDelay;
    private long maxDelay;
    private double multiplier;
    private List<String> retryableExceptions;
    
    // Getters and setters
    public int getMaxAttempts() { return maxAttempts; }
    public void setMaxAttempts(int maxAttempts) { this.maxAttempts = maxAttempts; }
    
    public long getInitialDelay() { return initialDelay; }
    public void setInitialDelay(long initialDelay) { this.initialDelay = initialDelay; }
    
    public long getMaxDelay() { return maxDelay; }
    public void setMaxDelay(long maxDelay) { this.maxDelay = maxDelay; }
    
    public double getMultiplier() { return multiplier; }
    public void setMultiplier(double multiplier) { this.multiplier = multiplier; }
    
    public List<String> getRetryableExceptions() { return retryableExceptions; }
    public void setRetryableExceptions(List<String> retryableExceptions) { this.retryableExceptions = retryableExceptions; }
}
@TuskConfig
public class DeadLetterConfig {
    private boolean enabled;
    private String topic;
    private int maxRetries;
    private String handler;
    
    // Getters and setters
    public boolean isEnabled() { return enabled; }
    public void setEnabled(boolean enabled) { this.enabled = enabled; }
    
    public String getTopic() { return topic; }
    public void setTopic(String topic) { this.topic = topic; }
    
    public int getMaxRetries() { return maxRetries; }
    public void setMaxRetries(int maxRetries) { this.maxRetries = maxRetries; }
    
    public String getHandler() { return handler; }
    public void setHandler(String handler) { this.handler = handler; }
}
@TuskConfig
public class ProjectionConfig {
    private boolean enabled;
    private String type;
    private String database;
    private String collection;
    private Map<String, String> handlers;
    private BatchConfig batch;
    
    // Getters and setters
    public boolean isEnabled() { return enabled; }
    public void setEnabled(boolean enabled) { this.enabled = enabled; }
    
    public String getType() { return type; }
    public void setType(String type) { this.type = type; }
    
    public String getDatabase() { return database; }
    public void setDatabase(String database) { this.database = database; }
    
    public String getCollection() { return collection; }
    public void setCollection(String collection) { this.collection = collection; }
    
    public Map<String, String> getHandlers() { return handlers; }
    public void setHandlers(Map<String, String> handlers) { this.handlers = handlers; }
    
    public BatchConfig getBatch() { return batch; }
    public void setBatch(BatchConfig batch) { this.batch = batch; }
}
@TuskConfig
public class BatchConfig {
    private int size;
    private long timeout;
    private boolean enabled;
    
    // Getters and setters
    public int getSize() { return size; }
    public void setSize(int size) { this.size = size; }
    
    public long getTimeout() { return timeout; }
    public void setTimeout(long timeout) { this.timeout = timeout; }
    
    public boolean isEnabled() { return enabled; }
    public void setEnabled(boolean enabled) { this.enabled = enabled; }
}
@TuskConfig
public class CqrsConfig {
    private boolean enabled;
    private CommandConfig command;
    private QueryConfig query;
    private EventBusConfig eventBus;
    
    // Getters and setters
    public boolean isEnabled() { return enabled; }
    public void setEnabled(boolean enabled) { this.enabled = enabled; }
    
    public CommandConfig getCommand() { return command; }
    public void setCommand(CommandConfig command) { this.command = command; }
    
    public QueryConfig getQuery() { return query; }
    public void setQuery(QueryConfig query) { this.query = query; }
    
    public EventBusConfig getEventBus() { return eventBus; }
    public void setEventBus(EventBusConfig eventBus) { this.eventBus = eventBus; }
}
@TuskConfig
public class CommandConfig {
    private String handlerPackage;
    private boolean validationEnabled;
    private String validationPackage;
    private Map<String, String> commandHandlers;
    
    // Getters and setters
    public String getHandlerPackage() { return handlerPackage; }
    public void setHandlerPackage(String handlerPackage) { this.handlerPackage = handlerPackage; }
    
    public boolean isValidationEnabled() { return validationEnabled; }
    public void setValidationEnabled(boolean validationEnabled) { this.validationEnabled = validationEnabled; }
    
    public String getValidationPackage() { return validationPackage; }
    public void setValidationPackage(String validationPackage) { this.validationPackage = validationPackage; }
    
    public Map<String, String> getCommandHandlers() { return commandHandlers; }
    public void setCommandHandlers(Map<String, String> commandHandlers) { this.commandHandlers = commandHandlers; }
}
@TuskConfig
public class QueryConfig {
    private String handlerPackage;
    private boolean cachingEnabled;
    private String cacheProvider;
    private int cacheTtl;
    private Map<String, String> queryHandlers;
    
    // Getters and setters
    public String getHandlerPackage() { return handlerPackage; }
    public void setHandlerPackage(String handlerPackage) { this.handlerPackage = handlerPackage; }
    
    public boolean isCachingEnabled() { return cachingEnabled; }
    public void setCachingEnabled(boolean cachingEnabled) { this.cachingEnabled = cachingEnabled; }
    
    public String getCacheProvider() { return cacheProvider; }
    public void setCacheProvider(String cacheProvider) { this.cacheProvider = cacheProvider; }
    
    public int getCacheTtl() { return cacheTtl; }
    public void setCacheTtl(int cacheTtl) { this.cacheTtl = cacheTtl; }
    
    public Map<String, String> getQueryHandlers() { return queryHandlers; }
    public void setQueryHandlers(Map<String, String> queryHandlers) { this.queryHandlers = queryHandlers; }
}
@TuskConfig
public class EventBusConfig {
    private String type;
    private String connectionString;
    private int maxConcurrency;
    private boolean asyncEnabled;
    
    // Getters and setters
    public String getType() { return type; }
    public void setType(String type) { this.type = type; }
    
    public String getConnectionString() { return connectionString; }
    public void setConnectionString(String connectionString) { this.connectionString = connectionString; }
    
    public int getMaxConcurrency() { return maxConcurrency; }
    public void setMaxConcurrency(int maxConcurrency) { this.maxConcurrency = maxConcurrency; }
    
    public boolean isAsyncEnabled() { return asyncEnabled; }
    public void setAsyncEnabled(boolean asyncEnabled) { this.asyncEnabled = asyncEnabled; }
}
@TuskConfig
public class MonitoringConfig {
    private String prometheusEndpoint;
    private boolean enabled;
    private Map<String, String> labels;
    private int scrapeInterval;
    private AlertingConfig alerting;
    
    // Getters and setters
    public String getPrometheusEndpoint() { return prometheusEndpoint; }
    public void setPrometheusEndpoint(String prometheusEndpoint) { this.prometheusEndpoint = prometheusEndpoint; }
    
    public boolean isEnabled() { return enabled; }
    public void setEnabled(boolean enabled) { this.enabled = enabled; }
    
    public Map<String, String> getLabels() { return labels; }
    public void setLabels(Map<String, String> labels) { this.labels = labels; }
    
    public int getScrapeInterval() { return scrapeInterval; }
    public void setScrapeInterval(int scrapeInterval) { this.scrapeInterval = scrapeInterval; }
    
    public AlertingConfig getAlerting() { return alerting; }
    public void setAlerting(AlertingConfig alerting) { this.alerting = alerting; }
}
@TuskConfig
public class AlertingConfig {
    private String slackWebhook;
    private String emailEndpoint;
    private Map<String, AlertRule> rules;
    
    // Getters and setters
    public String getSlackWebhook() { return slackWebhook; }
    public void setSlackWebhook(String slackWebhook) { this.slackWebhook = slackWebhook; }
    
    public String getEmailEndpoint() { return emailEndpoint; }
    public void setEmailEndpoint(String emailEndpoint) { this.emailEndpoint = emailEndpoint; }
    
    public Map<String, AlertRule> getRules() { return rules; }
    public void setRules(Map<String, AlertRule> rules) { this.rules = rules; }
}
@TuskConfig
public class AlertRule {
    private String condition;
    private String threshold;
    private String duration;
    private List<String> channels;
    private String severity;
    
    // Getters and setters
    public String getCondition() { return condition; }
    public void setCondition(String condition) { this.condition = condition; }
    
    public String getThreshold() { return threshold; }
    public void setThreshold(String threshold) { this.threshold = threshold; }
    
    public String getDuration() { return duration; }
    public void setDuration(String duration) { this.duration = duration; }
    
    public List<String> getChannels() { return channels; }
    public void setChannels(List<String> channels) { this.channels = channels; }
    
    public String getSeverity() { return severity; }
    public void setSeverity(String severity) { this.severity = severity; }
}

🏗️ Event-Driven TuskLang Configuration

event-driven.tsk

Event-Driven Architecture Configuration
[application]
name: "user-service"
version: "2.1.0"
environment: @env("ENVIRONMENT", "production")
[event_store]
type: "mongodb"
connection_string: @env("EVENT_STORE_CONNECTION", "mongodb://eventstore:27017")
database: "eventstore"
collection: "events"
[snapshot]
enabled: true
interval: 1000
storage: "mongodb"
[compression]
enabled: true
algorithm: "gzip"
level: 6
[serialization]
format: "json"
schema_registry: @env("SCHEMA_REGISTRY_URL", "http://schema-registry:8081")
schema_validation: true
custom_serializers {
    "UserCreated": "com.example.serializers.UserCreatedSerializer"
    "UserUpdated": "com.example.serializers.UserUpdatedSerializer"
    "UserDeleted": "com.example.serializers.UserDeletedSerializer"
}
[message_queue]
broker: "kafka"
brokers: [
    "kafka-1:9092",
    "kafka-2:9092",
    "kafka-3:9092"
]
topic: "user-events"
group_id: "user-service-group"
partitions: 6
replication_factor: 3
[retention]
time_ms: 604800000
size_bytes: 1073741824
cleanup_policy: "delete"
[consumer]
auto_offset_reset: "earliest"
max_poll_records: 500
max_poll_interval: 300000
session_timeout: 30000
heartbeat_interval: 3000
enable_auto_commit: false
auto_commit_interval: 5000
[producer]
acks: "all"
retries: 3
batch_size: 16384
linger_ms: 100
buffer_memory: 33554432
compression_type: "gzip"
[event_handlers]
handlers {
    "UserCreated": "com.example.handlers.UserCreatedHandler"
    "UserUpdated": "com.example.handlers.UserUpdatedHandler"
    "UserDeleted": "com.example.handlers.UserDeletedHandler"
    "UserActivated": "com.example.handlers.UserActivatedHandler"
    "UserDeactivated": "com.example.handlers.UserDeactivatedHandler"
}
[thread_pool]
core_size: 10
max_size: 50
queue_capacity: 1000
keep_alive_seconds: 60
thread_name_prefix: "event-handler-"
[retry]
max_attempts: 3
initial_delay: 1000
max_delay: 10000
multiplier: 2.0
retryable_exceptions: [
    "java.net.SocketTimeoutException",
    "java.net.ConnectException",
    "org.apache.kafka.common.errors.TimeoutException"
]
[dead_letter]
enabled: true
topic: "user-events-dlq"
max_retries: 3
handler: "com.example.handlers.DeadLetterHandler"
[projections]
enabled: true
type: "mongodb"
database: "projections"
collection: "user_projections"
handlers {
    "UserCreated": "com.example.projections.UserCreatedProjection"
    "UserUpdated": "com.example.projections.UserUpdatedProjection"
    "UserDeleted": "com.example.projections.UserDeletedProjection"
}
[batch]
size: 100
timeout: 5000
enabled: true
[cqrs]
enabled: true
[command]
handler_package: "com.example.commands"
validation_enabled: true
validation_package: "com.example.validators"
command_handlers {
    "CreateUser": "com.example.commands.CreateUserHandler"
    "UpdateUser": "com.example.commands.UpdateUserHandler"
    "DeleteUser": "com.example.commands.DeleteUserHandler"
    "ActivateUser": "com.example.commands.ActivateUserHandler"
}
[query]
handler_package: "com.example.queries"
caching_enabled: true
cache_provider: "redis"
cache_ttl: 300
query_handlers {
    "GetUser": "com.example.queries.GetUserHandler"
    "GetUsers": "com.example.queries.GetUsersHandler"
    "SearchUsers": "com.example.queries.SearchUsersHandler"
}
[event_bus]
type: "kafka"
connection_string: @env("KAFKA_BOOTSTRAP_SERVERS", "kafka:9092")
max_concurrency: 10
async_enabled: true
[monitoring]
prometheus_endpoint: "/actuator/prometheus"
enabled: true
labels {
    service: "user-service"
    version: "2.1.0"
    environment: @env("ENVIRONMENT", "production")
}
scrape_interval: 15
[alerting]
slack_webhook: @env.secure("SLACK_WEBHOOK")
email_endpoint: @env("ALERT_EMAIL")
[rules]
high_event_lag {
    condition: "event_lag > 1000"
    threshold: "1000 events"
    duration: "5m"
    channels: ["slack", "email"]
    severity: "warning"
}
event_processing_failure {
    condition: "event_processing_errors > 0.05"
    threshold: "5%"
    duration: "3m"
    channels: ["slack", "email"]
    severity: "critical"
}
dead_letter_queue_growth {
    condition: "dlq_size > 100"
    threshold: "100 messages"
    duration: "10m"
    channels: ["slack"]
    severity: "warning"
}
Dynamic event-driven configuration
[monitoring]
event_count: @query("SELECT COUNT(*) FROM events WHERE aggregate_type = 'User'")
snapshot_count: @query("SELECT COUNT(*) FROM snapshots WHERE aggregate_type = 'User'")
projection_lag: @metrics("projection_lag_events", 0)
event_size_avg: @metrics("event_size_bytes", 0)
consumer_lag: @metrics("kafka_consumer_lag", 0)
processing_rate: @metrics("events_processed_per_second", 0)
error_rate: @metrics("event_processing_errors_total", 0)

📊 Event Sourcing Implementation

Event Store Configuration

import org.tusklang.java.TuskLang;
import org.tusklang.java.config.TuskConfig;
@TuskConfig
public class EventStoreConfig {
    private String type;
    private String connectionString;
    private String database;
    private String collection;
    private SnapshotConfig snapshot;
    private SerializationConfig serialization;
    private IndexConfig indexes;
    
    // Getters and setters
    public String getType() { return type; }
    public void setType(String type) { this.type = type; }
    
    public String getConnectionString() { return connectionString; }
    public void setConnectionString(String connectionString) { this.connectionString = connectionString; }
    
    public String getDatabase() { return database; }
    public void setDatabase(String database) { this.database = database; }
    
    public String getCollection() { return collection; }
    public void setCollection(String collection) { this.collection = collection; }
    
    public SnapshotConfig getSnapshot() { return snapshot; }
    public void setSnapshot(SnapshotConfig snapshot) { this.snapshot = snapshot; }
    
    public SerializationConfig getSerialization() { return serialization; }
    public void setSerialization(SerializationConfig serialization) { this.serialization = serialization; }
    
    public IndexConfig getIndexes() { return indexes; }
    public void setIndexes(IndexConfig indexes) { this.indexes = indexes; }
}
@TuskConfig
public class IndexConfig {
    private List<String> indexes;
    private boolean autoCreate;
    private String indexType;
    
    // Getters and setters
    public List<String> getIndexes() { return indexes; }
    public void setIndexes(List<String> indexes) { this.indexes = indexes; }
    
    public boolean isAutoCreate() { return autoCreate; }
    public void setAutoCreate(boolean autoCreate) { this.autoCreate = autoCreate; }
    
    public String getIndexType() { return indexType; }
    public void setIndexType(String indexType) { this.indexType = indexType; }
}

event-store.tsk

[event_store]
type: "mongodb"
connection_string: @env("EVENT_STORE_CONNECTION", "mongodb://eventstore:27017")
database: "eventstore"
collection: "events"
[snapshot]
enabled: true
interval: 1000
storage: "mongodb"
[compression]
enabled: true
algorithm: "gzip"
level: 6
[serialization]
format: "json"
schema_registry: @env("SCHEMA_REGISTRY_URL", "http://schema-registry:8081")
schema_validation: true
[indexes]
indexes: [
    "aggregate_id",
    "aggregate_type",
    "event_type",
    "timestamp",
    "version"
]
auto_create: true
index_type: "btree"
Event store monitoring
[monitoring]
event_count: @query("SELECT COUNT(*) FROM events WHERE aggregate_type = 'User'")
snapshot_count: @query("SELECT COUNT(*) FROM snapshots WHERE aggregate_type = 'User'")
storage_size: @metrics("event_store_size_bytes", 0)
write_rate: @metrics("events_written_per_second", 0)
read_rate: @metrics("events_read_per_second", 0)

🔄 CQRS Implementation

Command and Query Separation

import org.tusklang.java.TuskLang;
import org.tusklang.java.config.TuskConfig;
@TuskConfig
public class CqrsConfig {
    private boolean enabled;
    private CommandConfig command;
    private QueryConfig query;
    private EventBusConfig eventBus;
    private ReadModelConfig readModel;
    
    // Getters and setters
    public boolean isEnabled() { return enabled; }
    public void setEnabled(boolean enabled) { this.enabled = enabled; }
    
    public CommandConfig getCommand() { return command; }
    public void setCommand(CommandConfig command) { this.command = command; }
    
    public QueryConfig getQuery() { return query; }
    public void setQuery(QueryConfig query) { this.query = query; }
    
    public EventBusConfig getEventBus() { return eventBus; }
    public void setEventBus(EventBusConfig eventBus) { this.eventBus = eventBus; }
    
    public ReadModelConfig getReadModel() { return readModel; }
    public void setReadModel(ReadModelConfig readModel) { this.readModel = readModel; }
}
@TuskConfig
public class ReadModelConfig {
    private String type;
    private String connectionString;
    private String database;
    private String collection;
    private CacheConfig cache;
    private ReplicationConfig replication;
    
    // Getters and setters
    public String getType() { return type; }
    public void setType(String type) { this.type = type; }
    
    public String getConnectionString() { return connectionString; }
    public void setConnectionString(String connectionString) { this.connectionString = connectionString; }
    
    public String getDatabase() { return database; }
    public void setDatabase(String database) { this.database = database; }
    
    public String getCollection() { return collection; }
    public void setCollection(String collection) { this.collection = collection; }
    
    public CacheConfig getCache() { return cache; }
    public void setCache(CacheConfig cache) { this.cache = cache; }
    
    public ReplicationConfig getReplication() { return replication; }
    public void setReplication(ReplicationConfig replication) { this.replication = replication; }
}
@TuskConfig
public class CacheConfig {
    private boolean enabled;
    private String provider;
    private String host;
    private int port;
    private int ttl;
    private int maxSize;
    
    // Getters and setters
    public boolean isEnabled() { return enabled; }
    public void setEnabled(boolean enabled) { this.enabled = enabled; }
    
    public String getProvider() { return provider; }
    public void setProvider(String provider) { this.provider = provider; }
    
    public String getHost() { return host; }
    public void setHost(String host) { this.host = host; }
    
    public int getPort() { return port; }
    public void setPort(int port) { this.port = port; }
    
    public int getTtl() { return ttl; }
    public void setTtl(int ttl) { this.ttl = ttl; }
    
    public int getMaxSize() { return maxSize; }
    public void setMaxSize(int maxSize) { this.maxSize = maxSize; }
}
@TuskConfig
public class ReplicationConfig {
    private boolean enabled;
    private String strategy;
    private int factor;
    private boolean syncReplication;
    
    // Getters and setters
    public boolean isEnabled() { return enabled; }
    public void setEnabled(boolean enabled) { this.enabled = enabled; }
    
    public String getStrategy() { return strategy; }
    public void setStrategy(String strategy) { this.strategy = strategy; }
    
    public int getFactor() { return factor; }
    public void setFactor(int factor) { this.factor = factor; }
    
    public boolean isSyncReplication() { return syncReplication; }
    public void setSyncReplication(boolean syncReplication) { this.syncReplication = syncReplication; }
}

cqrs.tsk

[cqrs]
enabled: true
[command]
handler_package: "com.example.commands"
validation_enabled: true
validation_package: "com.example.validators"
command_handlers {
    "CreateUser": "com.example.commands.CreateUserHandler"
    "UpdateUser": "com.example.commands.UpdateUserHandler"
    "DeleteUser": "com.example.commands.DeleteUserHandler"
    "ActivateUser": "com.example.commands.ActivateUserHandler"
}
[query]
handler_package: "com.example.queries"
caching_enabled: true
cache_provider: "redis"
cache_ttl: 300
query_handlers {
    "GetUser": "com.example.queries.GetUserHandler"
    "GetUsers": "com.example.queries.GetUsersHandler"
    "SearchUsers": "com.example.queries.SearchUsersHandler"
}
[read_model]
type: "mongodb"
connection_string: @env("READ_MODEL_CONNECTION", "mongodb://readmodel:27017")
database: "readmodel"
collection: "users"
[cache]
enabled: true
provider: "redis"
host: @env("REDIS_HOST", "redis")
port: @env("REDIS_PORT", "6379")
ttl: 300
max_size: 10000
[replication]
enabled: true
strategy: "eventual"
factor: 3
sync_replication: false
[event_bus]
type: "kafka"
connection_string: @env("KAFKA_BOOTSTRAP_SERVERS", "kafka:9092")
max_concurrency: 10
async_enabled: true
CQRS monitoring
[monitoring]
command_count: @metrics("commands_processed_total", 0)
query_count: @metrics("queries_processed_total", 0)
cache_hit_rate: @metrics("cache_hit_rate_percent", 85)
read_model_lag: @metrics("read_model_lag_events", 0)
write_model_lag: @metrics("write_model_lag_events", 0)

🎯 Best Practices

1. Event Design

- Use descriptive event names - Include all necessary data - Version events properly - Keep events immutable

2. Event Sourcing

- Use snapshots for performance - Implement proper projections - Handle event versioning - Monitor event store performance

3. CQRS

- Separate read and write models - Use appropriate consistency levels - Implement proper caching - Monitor read model lag

4. Message Queues

- Use appropriate partitioning - Configure replication - Implement dead letter queues - Monitor consumer lag

5. Event Processing

- Handle failures gracefully - Implement retry mechanisms - Use idempotent handlers - Monitor processing performance

🔧 Troubleshooting

Common Issues

1. Event Processing Failures - Check event handler configuration - Review retry settings - Monitor dead letter queue - Verify event schema

2. Read Model Lag - Check projection performance - Monitor event processing rate - Review database performance - Verify network connectivity

3. Message Queue Issues - Monitor consumer lag - Check partition distribution - Review retention policies - Verify broker connectivity

4. Event Store Problems - Check storage capacity - Monitor write performance - Review index configuration - Verify backup procedures

Debug Commands

Check event store
curl -X GET http://eventstore:2113/streams/user-events
Monitor Kafka consumer
kafka-consumer-groups.sh --bootstrap-server kafka:9092 --describe --group user-service-group
Check projections
curl -X GET http://projections:8080/projections
Monitor event processing
curl -X GET http://user-service:8080/actuator/metrics/events.processed

🚀 Next Steps

1. Implement event sourcing for data consistency 2. Set up CQRS for read/write separation 3. Configure message queues for async processing 4. Implement projections for read models 5. Monitor event processing for reliability

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