tessl/maven-ch-qos-logback--logback-core
Core infrastructure and basic components for the Logback logging framework, providing appenders, encoders, layouts, filters, and event processing pipeline
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Pending
network-logging.mddocs/
Network Logging
Network-based logging capabilities including TCP sockets, syslog protocol, email notifications, and SSL/TLS security for remote log transmission. Network appenders enable centralized logging and integration with log management systems.
Capabilities
SocketAppender
TCP socket-based appender for streaming log events to remote hosts with automatic reconnection and buffering.
/**
* TCP socket appender for remote log transmission.
* Supports automatic reconnection, queuing, and connection management.
*/
public class SocketAppender extends AppenderBase<ILoggingEvent> {
private String remoteHost;
private int port;
private Duration reconnectionDelay = Duration.valueOf("30 seconds");
private int queueSize = 128;
private boolean includeCallerData = false;
/**
* Set the remote host to connect to.
* @param host hostname or IP address
*/
public void setRemoteHost(String host);
/**
* Get the remote host.
* @return remote host
*/
public String getRemoteHost();
/**
* Set the remote port to connect to.
* @param port TCP port number
*/
public void setPort(int port);
/**
* Get the remote port.
* @return port number
*/
public int getPort();
/**
* Set the delay before attempting reconnection after connection failure.
* @param delay reconnection delay
*/
public void setReconnectionDelay(Duration delay);
/**
* Get the reconnection delay.
* @return reconnection delay
*/
public Duration getReconnectionDelay();
/**
* Set the queue size for buffering events during connection issues.
* @param queueSize maximum number of events to buffer
*/
public void setQueueSize(int queueSize);
/**
* Get the queue size.
* @return queue size
*/
public int getQueueSize();
/**
* Enable inclusion of caller data in transmitted events.
* @param includeCallerData true to include caller information
*/
public void setIncludeCallerData(boolean includeCallerData);
/**
* Check if caller data is included.
* @return true if caller data is included
*/
public boolean isIncludeCallerData();
@Override
protected void append(ILoggingEvent event);
@Override
public void start();
@Override
public void stop();
}SyslogAppender
Syslog protocol appender supporting RFC3164 and RFC5424 formats with facility and severity mapping.
/**
* Syslog protocol appender for integration with syslog daemons.
* Supports standard syslog facilities and severities.
*/
public class SyslogAppender extends AppenderBase<ILoggingEvent> {
private String syslogHost = "localhost";
private int port = 514;
private String facility = "USER";
private String suffixPattern;
private boolean throwExceptionOnWrite = true;
/**
* Set the syslog server hostname.
* @param syslogHost hostname of syslog server
*/
public void setSyslogHost(String syslogHost);
/**
* Get the syslog server hostname.
* @return syslog server hostname
*/
public String getSyslogHost();
/**
* Set the syslog server port.
* @param port UDP port (default 514)
*/
public void setPort(int port);
/**
* Get the syslog server port.
* @return port number
*/
public int getPort();
/**
* Set the syslog facility.
* @param facilityStr facility name (e.g., "USER", "LOCAL0", "MAIL")
*/
public void setFacility(String facilityStr);
/**
* Get the syslog facility.
* @return facility name
*/
public String getFacility();
/**
* Set the pattern for formatting the message part of syslog entries.
* @param suffixPattern message format pattern
*/
public void setSuffixPattern(String suffixPattern);
/**
* Get the suffix pattern.
* @return message format pattern
*/
public String getSuffixPattern();
/**
* Control whether to throw exceptions on write failures.
* @param throwExceptionOnWrite true to throw exceptions
*/
public void setThrowExceptionOnWrite(boolean throwExceptionOnWrite);
/**
* Check if exceptions are thrown on write failures.
* @return true if exceptions are thrown
*/
public boolean isThrowExceptionOnWrite();
@Override
protected void append(ILoggingEvent event);
@Override
public void start();
@Override
public void stop();
}SMTPAppender
Email-based appender for sending log events via SMTP with buffering and authentication support.
/**
* SMTP appender for email-based log notifications.
* Supports authentication, SSL/TLS, and event buffering.
*/
public class SMTPAppender extends AppenderBase<ILoggingEvent> {
private String to;
private String from;
private String subject = "Log4j Log Messages";
private String smtpHost;
private int smtpPort = 25;
private boolean STARTTLS = false;
private boolean SSL = false;
private String username;
private String password;
private int bufferSize = 512;
/**
* Set recipient email addresses (comma-separated).
* @param to recipient addresses
*/
public void setTo(String to);
/**
* Get recipient addresses.
* @return recipient addresses
*/
public String getTo();
/**
* Set sender email address.
* @param from sender address
*/
public void setFrom(String from);
/**
* Get sender address.
* @return sender address
*/
public String getFrom();
/**
* Set email subject line.
* @param subject email subject
*/
public void setSubject(String subject);
/**
* Get email subject.
* @return email subject
*/
public String getSubject();
/**
* Set SMTP server hostname.
* @param smtpHost SMTP server hostname
*/
public void setSMTPHost(String smtpHost);
/**
* Get SMTP server hostname.
* @return SMTP server hostname
*/
public String getSMTPHost();
/**
* Set SMTP server port.
* @param smtpPort SMTP port (default 25)
*/
public void setSMTPPort(int smtpPort);
/**
* Get SMTP server port.
* @return SMTP port
*/
public int getSMTPPort();
/**
* Enable STARTTLS for secure connection.
* @param startTLS true to enable STARTTLS
*/
public void setSTARTTLS(boolean startTLS);
/**
* Check if STARTTLS is enabled.
* @return true if STARTTLS is enabled
*/
public boolean isSTARTTLS();
/**
* Enable SSL for secure connection.
* @param ssl true to enable SSL
*/
public void setSSL(boolean ssl);
/**
* Check if SSL is enabled.
* @return true if SSL is enabled
*/
public boolean isSSL();
/**
* Set SMTP authentication username.
* @param username authentication username
*/
public void setUsername(String username);
/**
* Get authentication username.
* @return username
*/
public String getUsername();
/**
* Set SMTP authentication password.
* @param password authentication password
*/
public void setPassword(String password);
/**
* Get authentication password.
* @return password
*/
public String getPassword();
/**
* Set buffer size for batching events before sending email.
* @param bufferSize number of events to buffer
*/
public void setBufferSize(int bufferSize);
/**
* Get buffer size.
* @return buffer size
*/
public int getBufferSize();
@Override
protected void append(ILoggingEvent event);
@Override
public void start();
@Override
public void stop();
}SSL/TLS Support
SSLContextFactoryBean
Factory for creating SSL contexts with keystore and truststore configuration.
/**
* Factory for creating SSL contexts with custom keystore and truststore.
*/
public class SSLContextFactoryBean extends ContextAwareBase {
private KeyStoreFactoryBean keyStore;
private KeyStoreFactoryBean trustStore;
private String keyManagerPassword;
private String secureRandom;
private String protocol = "SSL";
/**
* Set the keystore factory for client certificates.
* @param keyStore keystore factory
*/
public void setKeyStore(KeyStoreFactoryBean keyStore);
/**
* Get the keystore factory.
* @return keystore factory
*/
public KeyStoreFactoryBean getKeyStore();
/**
* Set the truststore factory for server certificate validation.
* @param trustStore truststore factory
*/
public void setTrustStore(KeyStoreFactoryBean trustStore);
/**
* Get the truststore factory.
* @return truststore factory
*/
public KeyStoreFactoryBean getTrustStore();
/**
* Set the key manager password.
* @param keyManagerPassword password for key manager
*/
public void setKeyManagerPassword(String keyManagerPassword);
/**
* Get the key manager password.
* @return key manager password
*/
public String getKeyManagerPassword();
/**
* Set the secure random algorithm.
* @param secureRandomName secure random algorithm name
*/
public void setSecureRandom(String secureRandomName);
/**
* Get the secure random algorithm.
* @return secure random algorithm name
*/
public String getSecureRandom();
/**
* Set the SSL protocol.
* @param protocol SSL protocol (e.g., "TLS", "SSL")
*/
public void setProtocol(String protocol);
/**
* Get the SSL protocol.
* @return SSL protocol
*/
public String getProtocol();
/**
* Create the SSL context.
* @return configured SSL context
* @throws Exception if SSL context creation fails
*/
public SSLContext createContext() throws Exception;
}KeyStoreFactoryBean
Factory for creating keystores from various sources.
/**
* Factory for creating keystores from files, resources, or URLs.
*/
public class KeyStoreFactoryBean extends ContextAwareBase {
private String location;
private String password;
private String provider;
private String type = "JKS";
/**
* Set keystore location (file path, classpath resource, or URL).
* @param location keystore location
*/
public void setLocation(String location);
/**
* Get keystore location.
* @return keystore location
*/
public String getLocation();
/**
* Set keystore password.
* @param password keystore password
*/
public void setPassword(String password);
/**
* Get keystore password.
* @return keystore password
*/
public String getPassword();
/**
* Set security provider name.
* @param provider security provider name
*/
public void setProvider(String provider);
/**
* Get security provider name.
* @return security provider name
*/
public String getProvider();
/**
* Set keystore type.
* @param type keystore type (e.g., "JKS", "PKCS12")
*/
public void setType(String type);
/**
* Get keystore type.
* @return keystore type
*/
public String getType();
/**
* Create the keystore.
* @return loaded keystore
* @throws Exception if keystore creation fails
*/
public KeyStore createKeyStore() throws Exception;
}SSL Configuration Interface
/**
* Interface for SSL-configurable components.
*/
public interface SSLConfigurable {
/**
* Get the SSL context.
* @return SSL context
*/
SSLContext getSslContext();
/**
* Set SSL configuration.
* @param ssl SSL configuration
*/
void setSsl(SSL ssl);
/**
* Get SSL configuration.
* @return SSL configuration
*/
SSL getSsl();
}
/**
* SSL configuration aggregator.
*/
public class SSL implements SSLConfigurable {
private KeyStoreFactoryBean keyStore;
private KeyStoreFactoryBean trustStore;
private SSLContextFactoryBean sslContextFactoryBean;
/**
* Set keystore configuration.
* @param keyStore keystore factory
*/
public void setKeyStore(KeyStoreFactoryBean keyStore);
/**
* Get keystore configuration.
* @return keystore factory
*/
public KeyStoreFactoryBean getKeyStore();
/**
* Set truststore configuration.
* @param trustStore truststore factory
*/
public void setTrustStore(KeyStoreFactoryBean trustStore);
/**
* Get truststore configuration.
* @return truststore factory
*/
public KeyStoreFactoryBean getTrustStore();
@Override
public SSLContext getSslContext();
@Override
public void setSsl(SSL ssl);
@Override
public SSL getSsl();
}Server Components
ServerSocketAppender
Server-side socket appender for receiving log events from remote clients.
/**
* Server socket appender for receiving log events from remote clients.
*/
public class ServerSocketAppender<E> extends AppenderBase<E> {
private int port = 4560;
private String address;
private int clientQueueSize = 100;
private int timeout = 0;
/**
* Set the port to listen on.
* @param port listen port
*/
public void setPort(int port);
/**
* Get the listen port.
* @return port number
*/
public int getPort();
/**
* Set the address to bind to.
* @param address bind address (null for all interfaces)
*/
public void setAddress(String address);
/**
* Get the bind address.
* @return bind address
*/
public String getAddress();
/**
* Set client queue size.
* @param clientQueueSize queue size per client
*/
public void setClientQueueSize(int clientQueueSize);
/**
* Get client queue size.
* @return client queue size
*/
public int getClientQueueSize();
/**
* Set connection timeout.
* @param timeout timeout in milliseconds (0 = no timeout)
*/
public void setTimeout(int timeout);
/**
* Get connection timeout.
* @return timeout in milliseconds
*/
public int getTimeout();
@Override
protected void append(E eventObject);
@Override
public void start();
@Override
public void stop();
}Utility Classes
SocketConnector Interface
Interface for creating socket connections with custom implementations.
/**
* Interface for creating socket connections.
* Allows custom socket creation strategies.
*/
public interface SocketConnector {
/**
* Create a new socket connection to the specified address and port.
* @param address target address
* @param port target port
* @return connected socket
* @throws Exception if connection fails
*/
Socket newSocket(InetAddress address, int port) throws Exception;
/**
* Create a new socket connection to the specified host and port.
* @param host target hostname
* @param port target port
* @return connected socket
* @throws Exception if connection fails
*/
Socket newSocket(String host, int port) throws Exception;
}DefaultSocketConnector
Default implementation of SocketConnector.
/**
* Default socket connector implementation using standard TCP sockets.
*/
public class DefaultSocketConnector implements SocketConnector {
private int connectionTimeout = 0;
/**
* Set connection timeout.
* @param connectionTimeout timeout in milliseconds
*/
public void setConnectionTimeout(int connectionTimeout);
/**
* Get connection timeout.
* @return timeout in milliseconds
*/
public int getConnectionTimeout();
@Override
public Socket newSocket(InetAddress address, int port) throws Exception;
@Override
public Socket newSocket(String host, int port) throws Exception;
}SyslogConstants
Constants for syslog facilities and severities.
/**
* Constants for syslog protocol implementation.
*/
public class SyslogConstants {
// Syslog facilities
public static final int KERN_FACILITY = 0;
public static final int USER_FACILITY = 1;
public static final int MAIL_FACILITY = 2;
public static final int DAEMON_FACILITY = 3;
public static final int AUTH_FACILITY = 4;
public static final int SYSLOG_FACILITY = 5;
public static final int LPR_FACILITY = 6;
public static final int NEWS_FACILITY = 7;
public static final int UUCP_FACILITY = 8;
public static final int CRON_FACILITY = 9;
public static final int AUTHPRIV_FACILITY = 10;
public static final int FTP_FACILITY = 11;
public static final int LOCAL0_FACILITY = 16;
public static final int LOCAL1_FACILITY = 17;
public static final int LOCAL2_FACILITY = 18;
public static final int LOCAL3_FACILITY = 19;
public static final int LOCAL4_FACILITY = 20;
public static final int LOCAL5_FACILITY = 21;
public static final int LOCAL6_FACILITY = 22;
public static final int LOCAL7_FACILITY = 23;
// Syslog severities
public static final int EMERGENCY_SEVERITY = 0;
public static final int ALERT_SEVERITY = 1;
public static final int CRITICAL_SEVERITY = 2;
public static final int ERROR_SEVERITY = 3;
public static final int WARNING_SEVERITY = 4;
public static final int NOTICE_SEVERITY = 5;
public static final int INFO_SEVERITY = 6;
public static final int DEBUG_SEVERITY = 7;
}Usage Examples
Basic Socket Appender
import ch.qos.logback.core.net.SocketAppender;
import ch.qos.logback.core.util.Duration;
// Create socket appender for remote logging
SocketAppender socketAppender = new SocketAppender();
socketAppender.setContext(context);
socketAppender.setRemoteHost("log-server.example.com");
socketAppender.setPort(4560);
socketAppender.setReconnectionDelay(Duration.valueOf("10 seconds"));
socketAppender.setQueueSize(256);
socketAppender.setIncludeCallerData(true);
socketAppender.start();
// Use with other appenders
logger.addAppender(socketAppender);Syslog Appender Configuration
import ch.qos.logback.core.net.SyslogAppender;
// Configure syslog appender
SyslogAppender syslogAppender = new SyslogAppender();
syslogAppender.setContext(context);
syslogAppender.setSyslogHost("syslog.example.com");
syslogAppender.setPort(514);
syslogAppender.setFacility("LOCAL0");
syslogAppender.setSuffixPattern("%logger{20} - %msg");
syslogAppender.start();SMTP Appender with Authentication
import ch.qos.logback.core.net.SMTPAppender;
// Configure SMTP appender for error notifications
SMTPAppender smtpAppender = new SMTPAppender();
smtpAppender.setContext(context);
smtpAppender.setTo("admin@example.com,ops@example.com");
smtpAppender.setFrom("app@example.com");
smtpAppender.setSubject("Application Error Alert");
smtpAppender.setSMTPHost("smtp.example.com");
smtpAppender.setSMTPPort(587);
smtpAppender.setSTARTTLS(true);
smtpAppender.setUsername("app@example.com");
smtpAppender.setPassword("smtp-password");
smtpAppender.setBufferSize(1); // Send immediately on each event
smtpAppender.start();
// Use with error filter
ErrorFilter errorFilter = new ErrorFilter();
errorFilter.start();
smtpAppender.addFilter(errorFilter);SSL-Enabled Socket Appender
import ch.qos.logback.core.net.ssl.*;
// Create SSL configuration
KeyStoreFactoryBean keyStore = new KeyStoreFactoryBean();
keyStore.setContext(context);
keyStore.setLocation("client-keystore.jks");
keyStore.setPassword("keystore-password");
KeyStoreFactoryBean trustStore = new KeyStoreFactoryBean();
trustStore.setContext(context);
trustStore.setLocation("client-truststore.jks");
trustStore.setPassword("truststore-password");
SSLContextFactoryBean sslContext = new SSLContextFactoryBean();
sslContext.setContext(context);
sslContext.setKeyStore(keyStore);
sslContext.setTrustStore(trustStore);
SSL ssl = new SSL();
ssl.setKeyStore(keyStore);
ssl.setTrustStore(trustStore);
// Create SSL socket appender (custom implementation)
SSLSocketAppender sslAppender = new SSLSocketAppender();
sslAppender.setContext(context);
sslAppender.setRemoteHost("secure-log-server.example.com");
sslAppender.setPort(6514);
sslAppender.setSsl(ssl);
sslAppender.start();Server Socket for Log Collection
import ch.qos.logback.core.net.server.ServerSocketAppender;
// Create server socket appender to receive logs
ServerSocketAppender<ILoggingEvent> serverAppender = new ServerSocketAppender<>();
serverAppender.setContext(context);
serverAppender.setPort(4560);
serverAppender.setAddress("0.0.0.0"); // Listen on all interfaces
serverAppender.setClientQueueSize(1000);
serverAppender.setTimeout(30000); // 30 second timeout
serverAppender.start();
// Server will accept connections and forward events to attached appenders
FileAppender<ILoggingEvent> fileAppender = new FileAppender<>();
fileAppender.setContext(context);
fileAppender.setFile("collected-logs.log");
fileAppender.setEncoder(encoder);
fileAppender.start();
serverAppender.addAppender(fileAppender);Custom Network Appender
import ch.qos.logback.core.AppenderBase;
import java.net.DatagramSocket;
import java.net.DatagramPacket;
import java.net.InetAddress;
public class UDPAppender<E> extends AppenderBase<E> {
private String host = "localhost";
private int port = 9999;
private DatagramSocket socket;
@Override
protected void append(E eventObject) {
try {
String message = eventObject.toString();
byte[] buffer = message.getBytes("UTF-8");
DatagramPacket packet = new DatagramPacket(
buffer, buffer.length,
InetAddress.getByName(host), port
);
socket.send(packet);
} catch (Exception e) {
addError("Failed to send UDP packet", e);
}
}
@Override
public void start() {
try {
socket = new DatagramSocket();
super.start();
} catch (Exception e) {
addError("Failed to create UDP socket", e);
}
}
@Override
public void stop() {
if (socket != null && !socket.isClosed()) {
socket.close();
}
super.stop();
}
public void setHost(String host) {
this.host = host;
}
public void setPort(int port) {
this.port = port;
}
}Security Considerations
- SSL/TLS: Use SSL for sensitive log data transmission
- Authentication: Configure SMTP authentication for email appenders
- Firewall: Ensure appropriate firewall rules for network appenders
- Credentials: Store passwords securely, avoid hardcoding
- Certificate Validation: Properly configure truststores for SSL
- Network Timeouts: Set appropriate timeouts to prevent hanging connections
Performance and Reliability
- Buffering: Use queues and buffers to handle network latency
- Reconnection: Configure appropriate reconnection delays
- Fallback: Consider local fallback appenders for network failures
- Monitoring: Monitor network appender connection status
- Resource Management: Properly close network connections on shutdown
Install with Tessl CLI
npx tessl i tessl/maven-ch-qos-logback--logback-core