[duplicate-code] Session-Aware Logging Branching Duplication

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🔍 Duplicate Code Pattern: Session-Aware Logging Branching

Part of duplicate code analysis: #929

Summary

Multiple logging functions in internal/launcher/log_helpers.go contain identical if/else branching logic to handle sessionID-aware logging. This pattern appears in 3 functions with nearly identical structure, leading to ~45 lines of duplicated conditional logic.

Duplication Details

Pattern: Conditional Session Logging

• Severity: High

• Occurrences: 3 functions

• Locations:

  • internal/launcher/log_helpers.go lines 31-44 (logLaunchStart)
  • internal/launcher/log_helpers.go lines 95-106 (logTimeoutError)
  • internal/launcher/log_helpers.go lines 109-119 (logLaunchSuccess)

• Code Sample (from logLaunchStart):

  func (l *Launcher) logLaunchStart(serverID, sessionID string, serverCfg *config.ServerConfig, isDirectCommand bool) {
      if sessionID != "" {
          logger.LogInfoWithServer(serverID, "backend", "Launching MCP backend server for session: server=%s, session=%s, command=%s, args=%v", serverID, sessionID, serverCfg.Command, sanitize.SanitizeArgs(serverCfg.Args))
          log.Printf("[LAUNCHER] Starting MCP server for session: %s (session: %s)", serverID, sessionID)
          logLauncher.Printf("Launching new session server: serverID=%s, sessionID=%s, command=%s", serverID, sessionID, serverCfg.Command)
      } else {
          logger.LogInfoWithServer(serverID, "backend", "Launching MCP backend server: %s, command=%s, args=%v", serverID, serverCfg.Command, sanitize.SanitizeArgs(serverCfg.Args))
          log.Printf("[LAUNCHER] Starting MCP server: %s", serverID)
          logLauncher.Printf("Launching new server: serverID=%s, command=%s, inContainer=%v, isDirectCommand=%v",
              serverID, serverCfg.Command, l.runningInContainer, isDirectCommand)
      }
      log.Printf("[LAUNCHER] Command: %s", serverCfg.Command)
      log.Printf("[LAUNCHER] Args: %v", sanitize.SanitizeArgs(serverCfg.Args))
  }

• Similar Pattern (from logLaunchSuccess):

  func (l *Launcher) logLaunchSuccess(serverID, sessionID string) {
      if sessionID != "" {
          logger.LogInfoWithServer(serverID, "backend", "Successfully launched MCP backend server for session: server=%s, session=%s", serverID, sessionID)
          log.Printf("[LAUNCHER] Successfully launched: %s (session: %s)", serverID, sessionID)
          logLauncher.Printf("Session connection established: serverID=%s, sessionID=%s", serverID, sessionID)
      } else {
          logger.LogInfoWithServer(serverID, "backend", "Successfully launched MCP backend server: %s", serverID)
          log.Printf("[LAUNCHER] Successfully launched: %s", serverID)
          logLauncher.Printf("Connection established: serverID=%s", serverID)
      }
  }

Impact Analysis

• Maintainability: High impact - Changes to session handling must be replicated across 3 functions, increasing risk of inconsistent behavior
• Bug Risk: Medium-High - If one function is updated for session handling but others aren't, logging behavior becomes inconsistent
• Code Bloat: ~45 lines of duplicated branching logic
• Testing Complexity: Each function requires separate test cases for session vs non-session scenarios

Refactoring Recommendations

Option 1: Extract Session-Aware Logging Helper (Recommended)

• Extract common pattern to: internal/launcher/session_logger.go
• Estimated effort: 2-3 hours
• Benefits:
  • Single source of truth for session-aware logging
  • Consistent logging format across all launcher operations
  • Easier to modify logging behavior
• Implementation:

  // sessionLogger wraps triple logging with session awareness
  type sessionLogger struct {
      serverID string
      sessionID string
  }
  
  func (sl *sessionLogger) logInfo(category, fileMsg, stdoutMsg, debugMsg string, args ...interface{}) {
      if sl.sessionID != "" {
          logger.LogInfoWithServer(sl.serverID, category, fileMsg+" for session: session="+sl.sessionID, args...)
          log.Printf(stdoutMsg+" (session: "+sl.sessionID+")", args...)
          logLauncher.Printf(debugMsg+", sessionID="+sl.sessionID, args...)
      } else {
          logger.LogInfoWithServer(sl.serverID, category, fileMsg, args...)
          log.Printf(stdoutMsg, args...)
          logLauncher.Printf(debugMsg, args...)
      }
  }

Option 2: Use sessionSuffix() More Consistently

• Leverage existing sessionSuffix() helper more broadly
• Estimated effort: 1-2 hours
• Benefits: Simpler, less refactoring needed
• Trade-off: Still requires manual if/else in some cases

Implementation Checklist

• Review duplication findings with team
• Decide on refactoring approach (Option 1 vs Option 2)
• Create session-aware logging helper utility
• Refactor logLaunchStart(), logTimeoutError(), logLaunchSuccess()
• Update tests to cover new utility
• Verify no functionality broken
• Consider extending pattern to other launcher functions

Parent Issue

See parent analysis report: #929
Related to #929

AI generated by Duplicate Code Detector

• expires on Feb 21, 2026, 10:12 AM UTC