Utilities and Helpers

/**
 * Interface for resolving artifact URIs for Mesos Fetcher
 * Provides URI resolution for files that need to be distributed to tasks
 */
public interface MesosArtifactResolver {
    /**
     * Resolve artifact URI for the given remote file path
     * @param remoteFile - Path to file as it should appear in task container
     * @return Optional URL where file can be fetched, empty if not found
     */
    Option<URL> resolve(Path remoteFile);
}

/**
 * HTTP server for distributing artifacts to Mesos tasks via Mesos Fetcher
 * Extends resolver interface with server lifecycle management
 */
public interface MesosArtifactServer extends MesosArtifactResolver {
    /**
     * Add a local file path for distribution to tasks
     * @param path - Local file system path to serve
     * @param remoteFile - Path as it should appear in task containers
     * @return URL where file can be fetched by Mesos Fetcher
     */
    URL addPath(Path path, Path remoteFile);
    
    /**
     * Stop the artifact server and cleanup resources
     * Closes all connections and releases server port
     */
    void stop();
}

/**
 * HTTP server implementation for artifact distribution
 * Provides secure, scalable file distribution to Mesos tasks
 */
public class MesosArtifactServerImpl implements MesosArtifactServer {
    /**
     * Create artifact server with configuration
     * @param hostname - Hostname for server binding
     * @param port - Port for server (0 for automatic assignment)
     * @param sslConfig - Optional SSL configuration for secure distribution
     */
    public MesosArtifactServerImpl(String hostname, int port, SSLConfiguration sslConfig);
    
    /**
     * Start the artifact server
     * @return Server URL for artifact access
     */
    public URL start();
    
    /**
     * Get the server port (useful when auto-assigned)
     * @return Actual port number being used
     */
    public int getPort();
}

import org.apache.flink.mesos.util.MesosArtifactServer;
import org.apache.flink.mesos.util.MesosArtifactServerImpl;

// Create and start artifact server
MesosArtifactServerImpl server = new MesosArtifactServerImpl("master-host", 0, null);
URL serverUrl = server.start();

// Add job JAR for distribution
Path jobJarPath = Paths.get("/path/to/job.jar");
URL jarUrl = server.addPath(jobJarPath, Paths.get("lib/job.jar"));

// Add configuration files
Path configPath = Paths.get("/opt/flink/conf/flink-conf.yaml");
URL configUrl = server.addPath(configPath, Paths.get("conf/flink-conf.yaml"));

// URLs can now be used in Mesos TaskInfo URIs
// Mesos Fetcher will download files to task containers

/**
 * Collection of Mesos-related utility methods
 * Provides configuration creation and management functions
 */
public class MesosUtils {
    /**
     * Create Mesos scheduler configuration from Flink configuration
     * @param config - Flink configuration with Mesos settings
     * @param hostname - Hostname for framework registration
     * @return Configured MesosConfiguration for scheduler
     */
    public static MesosConfiguration createMesosSchedulerConfiguration(Configuration config, 
                                                                       String hostname);
    
    /**
     * Create TaskManager parameters from configuration
     * @param config - Flink configuration
     * @param logger - Logger for parameter validation messages
     * @return Configured TaskManager parameters for Mesos deployment
     */
    public static MesosTaskManagerParameters createTmParameters(Configuration config, 
                                                                Logger logger);
    
    /**
     * Create container specification from configuration
     * @param config - Flink configuration with container settings
     * @return Container specification for TaskManager deployment
     */
    public static ContainerSpecification createContainerSpec(Configuration config);
    
    /**
     * Apply configuration overlays to container specification
     * Merges environment variables, volumes, and other container settings
     * @param config - Flink configuration
     * @param containerSpec - Base container specification to modify
     */
    public static void applyOverlays(Configuration config, 
                                     ContainerSpecification containerSpec);
    
    /**
     * Load and merge Flink configuration from multiple sources
     * @param baseConfig - Base configuration
     * @param logger - Logger for configuration loading messages
     * @return Merged configuration with all sources applied
     */
    public static Configuration loadConfiguration(Configuration baseConfig, Logger logger);
}

import org.apache.flink.configuration.Configuration;
import org.apache.flink.mesos.util.MesosUtils;
import org.apache.flink.mesos.configuration.MesosOptions;

// Create base configuration
Configuration config = new Configuration();
config.setString(MesosOptions.MASTER_URL, "mesos://master:5050");
config.setString(MesosOptions.RESOURCEMANAGER_FRAMEWORK_NAME, "flink-cluster");
config.setDouble("taskmanager.numberOfTaskSlots", 4.0);
config.setString("taskmanager.memory.process.size", "2g");

// Create Mesos scheduler configuration
MesosConfiguration mesosConfig = MesosUtils.createMesosSchedulerConfiguration(
    config, "cluster-master"
);

// Create TaskManager parameters
MesosTaskManagerParameters tmParams = MesosUtils.createTmParameters(
    config, LoggerFactory.getLogger(MyClass.class)
);

// Create container specification
ContainerSpecification containerSpec = MesosUtils.createContainerSpec(config);
MesosUtils.applyOverlays(config, containerSpec);

/**
 * Collection of Mesos protobuf and resource utility methods
 * Provides helpers for creating Mesos protocol buffer objects
 */
public class Utils {
    /**
     * Create CPU resource specification
     * @param cpus - Number of CPU cores
     * @return Mesos Resource for CPU allocation
     */
    public static Protos.Resource cpus(double cpus);
    
    /**
     * Create memory resource specification  
     * @param mem - Memory amount in MB
     * @return Mesos Resource for memory allocation
     */
    public static Protos.Resource mem(double mem);
    
    /**
     * Create GPU resource specification
     * @param gpus - Number of GPU units
     * @return Mesos Resource for GPU allocation
     */
    public static Protos.Resource gpus(double gpus);
    
    /**
     * Create disk resource specification
     * @param disk - Disk space in MB
     * @return Mesos Resource for disk allocation
     */
    public static Protos.Resource disk(double disk);
    
    /**
     * Create network resource specification
     * @param bandwidth - Network bandwidth in Mbps
     * @return Mesos Resource for network allocation
     */
    public static Protos.Resource network(double bandwidth);
    
    /**
     * Create port range resource specification
     * @param begin - Start of port range (inclusive)
     * @param end - End of port range (inclusive)
     * @return Mesos Resource for port range allocation
     */
    public static Protos.Resource ports(long begin, long end);
    
    /**
     * Create environment variable for Mesos tasks
     * @param key - Environment variable name
     * @param value - Environment variable value
     * @return Mesos Environment.Variable object
     */
    public static Protos.Environment.Variable variable(String key, String value);
    
    /**
     * Create URI specification for Mesos Fetcher
     * @param uri - URI to fetch
     * @param extract - Whether to extract archives
     * @param executable - Whether file should be executable
     * @param cache - Whether to cache the URI
     * @param outputFile - Optional output filename
     * @return Mesos CommandInfo.URI object
     */
    public static Protos.CommandInfo.URI uri(String uri, 
                                             boolean extract, 
                                             boolean executable, 
                                             boolean cache, 
                                             String outputFile);
    
    /**
     * Convert range values to string representation
     * @param ranges - List of Value.Range objects
     * @return String representation of ranges (e.g., "8000-8010,9000-9010")
     */
    public static String rangeValues(List<Protos.Value.Range> ranges);
    
    /**
     * Convert Mesos resource to string representation
     * @param resource - Mesos Resource object
     * @return Human-readable string representation
     */
    public static String toString(Protos.Resource resource);
}

import org.apache.flink.mesos.Utils;
import org.apache.mesos.Protos;

// Create resource specifications
Protos.Resource cpuResource = Utils.cpus(2.0);
Protos.Resource memResource = Utils.mem(2048.0);
Protos.Resource diskResource = Utils.disk(1024.0);
Protos.Resource portsResource = Utils.ports(8000, 8010);

// Create environment variables
Protos.Environment.Variable javaHome = Utils.variable("JAVA_HOME", "/usr/lib/jvm/java-8");
Protos.Environment.Variable flinkHome = Utils.variable("FLINK_HOME", "/opt/flink");

// Create URIs for Mesos Fetcher
Protos.CommandInfo.URI jobJarUri = Utils.uri(
    "http://artifact-server:8080/job.jar",
    false, // don't extract
    false, // not executable
    true,  // cache
    "lib/job.jar" // output filename
);

Protos.CommandInfo.URI configUri = Utils.uri(
    "http://artifact-server:8080/flink-conf.yaml",
    false, false, true, "conf/flink-conf.yaml"
);

// Use in TaskInfo creation
Protos.TaskInfo taskInfo = Protos.TaskInfo.newBuilder()
    .addAllResources(Arrays.asList(cpuResource, memResource, diskResource, portsResource))
    .setCommand(Protos.CommandInfo.newBuilder()
        .addAllUris(Arrays.asList(jobJarUri, configUri))
        .setEnvironment(Protos.Environment.newBuilder()
            .addAllVariables(Arrays.asList(javaHome, flinkHome))
        )
    )
    .build();

/**
 * Represents allocated Mesos resources for a task
 * Provides resource information and allocation details
 */
public class MesosResourceAllocation {
    /**
     * Create resource allocation from Mesos resources
     * @param resources - List of allocated Mesos resources
     */
    public MesosResourceAllocation(List<Protos.Resource> resources);
    
    /**
     * Get allocated CPU cores
     * @return Number of CPU cores allocated
     */
    public double cpus();
    
    /**
     * Get allocated memory in megabytes
     * @return Memory allocation in MB
     */
    public double memoryMB();
    
    /**
     * Get allocated disk space in megabytes
     * @return Disk allocation in MB
     */
    public double diskMB();
    
    /**
     * Get allocated network bandwidth in Mbps
     * @return Network bandwidth allocation
     */
    public double networkMbps();
    
    /**
     * Get allocated GPU units
     * @return Number of GPUs allocated
     */
    public double gpus();
    
    /**
     * Get allocated port ranges
     * @return List of allocated port ranges
     */
    public List<Protos.Value.Range> ports();
    
    /**
     * Get all allocated Mesos resources
     * @return Complete list of Mesos Resource objects
     */
    public List<Protos.Resource> mesosResources();
    
    /**
     * Check if allocation satisfies resource requirements
     * @param requirements - Required resource amounts
     * @return true if allocation meets or exceeds requirements
     */
    public boolean satisfies(ResourceProfile requirements);
}

// Configuration validation utility
public class MesosConfigValidator {
    public static void validateConfiguration(Configuration config) {
        // Validate required settings
        if (!config.contains(MesosOptions.MASTER_URL)) {
            throw new IllegalArgumentException("Mesos master URL is required");
        }
        
        // Validate resource requirements
        double cpus = config.getDouble("mesos.resourcemanager.tasks.cpus", 1.0);
        if (cpus <= 0) {
            throw new IllegalArgumentException("CPU requirement must be positive");
        }
        
        // Validate framework settings
        String frameworkName = config.getString(MesosOptions.RESOURCEMANAGER_FRAMEWORK_NAME);
        if (frameworkName == null || frameworkName.trim().isEmpty()) {
            throw new IllegalArgumentException("Framework name cannot be empty");
        }
        
        // Validate timeout settings
        int failoverTimeout = config.getInteger(MesosOptions.FAILOVER_TIMEOUT_SECONDS);
        if (failoverTimeout < 0) {
            throw new IllegalArgumentException("Failover timeout cannot be negative");
        }
    }
}

// Resource calculation utilities  
public class ResourceCalculator {
    public static ResourceProfile calculateTaskManagerProfile(Configuration config) {
        // Calculate memory requirements
        MemorySize processMemory = TaskExecutorResourceUtils.extractTotalProcessMemoryConfiguration(config);
        MemorySize managedMemory = TaskExecutorResourceUtils.extractManagedMemoryConfiguration(config);
        
        // Calculate CPU requirements
        double cpuCores = config.getDouble("taskmanager.numberOfTaskSlots", 1.0);
        
        // Calculate disk requirements  
        long diskSize = config.getLong("mesos.resourcemanager.tasks.disk", 1024);
        
        return ResourceProfile.newBuilder()
            .setCpuCores(cpuCores)
            .setTaskHeapMemory(processMemory)
            .setManagedMemory(managedMemory)
            .build();
    }
    
    public static boolean isResourceSufficient(ResourceProfile required, 
                                               MesosResourceAllocation available) {
        return available.cpus() >= required.getCpuCores().getValue() &&
               available.memoryMB() >= required.getTotalMemory().getMebiBytes() &&
               available.diskMB() >= 1024; // Minimum disk requirement
    }
}

// Container image utilities
public class ContainerImageUtils {
    public static String resolveImageName(Configuration config) {
        String imageName = config.getString("mesos.resourcemanager.tasks.container.docker.image");
        
        if (imageName == null) {
            // Default image based on Flink version
            String flinkVersion = config.getString("flink.version", "1.13.6");
            String scalaVersion = config.getString("scala.version", "2.11");
            imageName = String.format("flink:%s-scala_%s", flinkVersion, scalaVersion);
        }
        
        return imageName;
    }
    
    public static List<String> buildDockerParameters(Configuration config) {
        List<String> parameters = new ArrayList<>();
        
        // Network configuration
        String network = config.getString("mesos.resourcemanager.tasks.container.docker.network", "HOST");
        parameters.add("--net=" + network);
        
        // Volume mounts
        String volumes = config.getString("mesos.resourcemanager.tasks.container.volumes", "");
        for (String volume : volumes.split(",")) {
            if (!volume.trim().isEmpty()) {
                parameters.add("-v");
                parameters.add(volume.trim());
            }
        }
        
        return parameters;
    }
}

// Enhanced logging utilities
public class MesosLoggingUtils {
    public static void logResourceAllocation(Logger logger, MesosResourceAllocation allocation) {
        logger.info("Resource allocation: CPU={}, Memory={}MB, Disk={}MB, GPU={}", 
                   allocation.cpus(), allocation.memoryMB(), 
                   allocation.diskMB(), allocation.gpus());
    }
    
    public static void logConfigurationSummary(Logger logger, Configuration config) {
        logger.info("Mesos configuration summary:");
        logger.info("  Master URL: {}", config.getString(MesosOptions.MASTER_URL));
        logger.info("  Framework: {}", config.getString(MesosOptions.RESOURCEMANAGER_FRAMEWORK_NAME));
        logger.info("  Resources: CPU={}, Memory={}", 
                   config.getDouble("mesos.resourcemanager.tasks.cpus", 1.0),
                   config.getString("taskmanager.memory.process.size", "1g"));
    }
}

/**
 * SSL configuration for artifact server
 */
public class SSLConfiguration {
    public String getKeystorePath();
    public String getKeystorePassword();
    public String getTruststorePath();
    public String getTruststorePassword();
    public boolean isClientAuthRequired();
}

/**
 * Container specification for TaskManager deployment
 */
public class ContainerSpecification {
    public String getImageName();
    public ContainerType getType();
    public Map<String, String> getEnvironmentVariables();
    public List<VolumeMount> getVolumeMounts();
    public List<String> getCommand();
    public ResourceProfile getResourceProfile();
}

/**
 * Volume mount specification
 */
public class VolumeMount {
    public String getHostPath();
    public String getContainerPath();
    public MountMode getMode(); // READ_ONLY, READ_WRITE
}

/**
 * Artifact distribution statistics
 */
public class ArtifactStats {
    public int getTotalArtifacts();
    public long getTotalSizeBytes();
    public int getDownloadCount();
    public double getAverageDownloadTime();
    public List<String> getMostRequestedArtifacts();
}