[duplicate-code] Duplicate Code Pattern: Docker Inspect Commands

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🔍 Duplicate Code Pattern: Docker Inspect Commands

Part of duplicate code analysis: #249

Summary

Three functions in internal/config/env_validation.go implement nearly identical Docker inspect command patterns with only variations in the format template and output parsing. This duplication creates maintenance burden for Docker interaction logic.

Duplication Details

Pattern: Docker Inspect Command Execution

• Severity: Medium
• Occurrences: 3 instances
• Locations:
  • internal/config/env_validation.go:checkPortMapping() (lines 211-230)
  • internal/config/env_validation.go:checkStdinInteractive() (lines 232-246)
  • internal/config/env_validation.go:checkLogDirMounted() (lines 248-263)

Code Sample - checkPortMapping:

func checkPortMapping(containerID, port string) (bool, error) {
    if err := validateContainerID(containerID); err != nil {
        return false, err
    }
    
    // Use docker inspect to get port bindings
    cmd := exec.Command("docker", "inspect", "--format", "{{json .NetworkSettings.Ports}}", containerID)
    output, err := cmd.Output()
    if err != nil {
        return false, fmt.Errorf("docker inspect failed: %w", err)
    }
    
    // Parse the port from the output
    portKey := fmt.Sprintf("%s/tcp", port)
    outputStr := string(output)
    
    // Check if the port is in the output with a host binding
    return strings.Contains(outputStr, portKey) && strings.Contains(outputStr, "HostPort"), nil
}

Code Sample - checkStdinInteractive:

func checkStdinInteractive(containerID string) bool {
    if err := validateContainerID(containerID); err != nil {
        return false
    }
    
    // Use docker inspect to check stdin_open
    cmd := exec.Command("docker", "inspect", "--format", "{{.Config.OpenStdin}}", containerID)
    output, err := cmd.Output()
    if err != nil {
        return false
    }
    
    return strings.TrimSpace(string(output)) == "true"
}

Code Sample - checkLogDirMounted:

func checkLogDirMounted(containerID, logDir string) bool {
    if err := validateContainerID(containerID); err != nil {
        return false
    }
    
    // Use docker inspect to get mounts
    cmd := exec.Command("docker", "inspect", "--format", "{{json .Mounts}}", containerID)
    output, err := cmd.Output()
    if err != nil {
        return false
    }
    
    // Check if the log directory is in the mounts
    return strings.Contains(string(output), logDir)
}

Impact Analysis

• Maintainability: Changes to Docker command execution (e.g., adding timeout, changing error handling) must be replicated across 3 functions
• Bug Risk: Inconsistent error handling - checkPortMapping returns error, while others return bool only
• Code Bloat: ~50 lines of duplicated Docker command execution code
• Testability: Harder to mock/test Docker interactions when logic is duplicated

Refactoring Recommendations

1. Extract Generic Docker Inspect Helper

   • Create dockerInspect(containerID, formatTemplate string) (string, error) in env_validation.go
   • Handles:
     • Container ID validation
     • Command execution
     • Error handling
     • Output conversion
   • Example usage:

     func checkPortMapping(containerID, port string) (bool, error) {
         output, err := dockerInspect(containerID, "{{json .NetworkSettings.Ports}}")
         if err != nil {
             return false, err
         }
         portKey := fmt.Sprintf("%s/tcp", port)
         return strings.Contains(output, portKey) && strings.Contains(output, "HostPort"), nil
     }

   • Estimated effort: 1-2 hours
   • Benefits:
     • Single place to handle Docker command execution
     • Consistent error handling
     • Easier to add timeouts or retries

2. Standardize Return Types

   • Make all check functions return (bool, error) for consistency
   • Currently: checkPortMapping returns error, others don't
   • Estimated effort: 30 minutes
   • Benefits: Consistent error propagation

3. Add Command Timeout Support

   • Use exec.CommandContext with timeout to prevent hanging on Docker issues
   • Estimated effort: 30 minutes
   • Benefits: More robust error handling

Implementation Checklist

• Review duplication findings
• Design generic dockerInspect function signature
• Implement dockerInspect with timeout support
• Refactor checkPortMapping to use generic function
• Refactor checkStdinInteractive to use generic function
• Refactor checkLogDirMounted to use generic function
• Standardize return types across all check functions
• Update tests to verify behavior unchanged
• Add tests for timeout scenarios

Parent Issue

See parent analysis report: #249
Related to #249

AI generated by Duplicate Code Detector

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This issue was automatically closed because it expired on 2026-01-14T17:14:23.890Z.