diff options
Diffstat (limited to 'internal/server')
| -rw-r--r-- | internal/server/server.go | 83 |
1 files changed, 74 insertions, 9 deletions
diff --git a/internal/server/server.go b/internal/server/server.go index 761880d..15b86a1 100644 --- a/internal/server/server.go +++ b/internal/server/server.go @@ -1,3 +1,25 @@ +// Package server provides the DTail server implementation that handles SSH +// connections from DTail clients and processes distributed log operations. +// The server acts as an SSH daemon listening on port 2222 by default, providing +// secure multi-user access to log files with proper authentication and resource management. +// +// Key features: +// - SSH server with configurable authentication methods +// - Multi-user support with different privilege levels +// - Resource management with configurable connection and operation limits +// - Background services for scheduled and continuous monitoring jobs +// - Handler routing system for different client operations +// - Real-time statistics and connection tracking +// +// The server supports several user types: +// - Regular users: Standard SSH public key authentication +// - Health users: Special authentication for health checking +// - Scheduled users: Background jobs with IP-based access control +// - Continuous users: Long-running monitoring jobs with IP-based access control +// +// Each connection is handled in its own goroutine with proper resource cleanup +// and statistics tracking. The server enforces connection limits to prevent +// resource exhaustion and provides graceful shutdown capabilities. package server import ( @@ -18,23 +40,50 @@ import ( gossh "golang.org/x/crypto/ssh" ) -// Server is the main server data structure. +// Server represents the main DTail server instance that manages SSH connections, +// user authentication, and distributed log operations. It coordinates multiple +// subsystems including connection handling, resource limiting, and background services. type Server struct { - // Various server statistics counters. + // stats tracks real-time server statistics including connection counts, + // active operations, and resource utilization metrics stats stats - // SSH server configuration. + + // sshServerConfig contains the SSH server configuration including + // supported key exchanges, ciphers, MACs, and authentication callbacks sshServerConfig *gossh.ServerConfig - // To control the max amount of concurrent cats. + + // catLimiter controls the maximum number of concurrent cat operations + // to prevent resource exhaustion from too many simultaneous file reads catLimiter chan struct{} - // To control the max amount of concurrent tails. + + // tailLimiter controls the maximum number of concurrent tail operations + // to manage long-running file monitoring connections tailLimiter chan struct{} - // To run scheduled tasks (if configured) + + // sched manages scheduled MapReduce jobs that run at specified intervals + // with configurable authentication and access control sched *scheduler - // Mointor log files for pattern (if configured) + + // cont manages continuous monitoring jobs that watch log files for + // specific patterns and trigger actions when matches are found cont *continuous } -// New returns a new server. +// New creates and initializes a new DTail server instance with all necessary +// components configured. This constructor sets up SSH server configuration, +// resource limiters, authentication callbacks, and background services. +// +// Returns: +// *Server: Fully configured server instance ready to start +// +// The initialization process: +// 1. Creates SSH server configuration with cryptographic settings +// 2. Sets up resource limiters for concurrent operations +// 3. Configures authentication callbacks for different user types +// 4. Generates or loads SSH host keys +// 5. Initializes background services (scheduler and continuous monitoring) +// +// The server is ready to call Start() after construction. func New() *Server { dlog.Server.Info("Starting server", version.String()) @@ -64,7 +113,23 @@ func New() *Server { return &s } -// Start the server. +// Start begins the server operation by binding to the configured address, +// starting background services, and entering the main connection acceptance loop. +// This method handles the complete server lifecycle including graceful shutdown. +// +// Parameters: +// ctx: Context for controlling server shutdown and cancellation +// +// Returns: +// int: Exit status code (currently always returns 0) +// +// The startup process: +// 1. Binds to the configured SSH port and address +// 2. Starts statistics collection in background +// 3. Starts scheduled job processor +// 4. Starts continuous monitoring processor +// 5. Begins the main connection acceptance loop +// 6. Blocks until context cancellation triggers shutdown func (s *Server) Start(ctx context.Context) int { dlog.Server.Info("Starting server") bindAt := fmt.Sprintf("%s:%d", config.Server.SSHBindAddress, config.Common.SSHPort) |