Part of duplicate code analysis: #2361

Summary

internal/cmd/flags_difc.go and internal/cmd/flags_logging.go together contain 9 trivial one-to-two-line getDefault*() functions that each wrap a single os.Getenv() or envutil.Get*() call. While each function is individually small, the pattern is repeated identically across both files and could be consolidated with a shared helper.

Duplication Details

Pattern: Single-Expression getDefault*() Wrappers

• Severity: Medium
• Occurrences: 9 near-identical functions (5 in flags_difc.go, 4 in flags_logging.go)
• Locations:
  • internal/cmd/flags_difc.go lines 63–85:

    func getDefaultDIFCSinkServerIDs() string {
        return os.Getenv("MCP_GATEWAY_GUARDS_SINK_SERVER_IDS")
    }
    func getDefaultGuardPolicyJSON() string {
        return os.Getenv("MCP_GATEWAY_GUARD_POLICY_JSON")
    }
    func getDefaultAllowOnlyScopeOwner() string {
        return os.Getenv("MCP_GATEWAY_ALLOWONLY_SCOPE_OWNER")
    }
    func getDefaultAllowOnlyScopeRepo() string {
        return os.Getenv("MCP_GATEWAY_ALLOWONLY_SCOPE_REPO")
    }
    func getDefaultAllowOnlyMinIntegrity() string {
        return os.Getenv("MCP_GATEWAY_ALLOWONLY_MIN_INTEGRITY")
    }

  • internal/cmd/flags_logging.go lines 35–55:

    func getDefaultLogDir() string {
        return envutil.GetEnvString("MCP_GATEWAY_LOG_DIR", config.DefaultLogDir)
    }
    func getDefaultPayloadDir() string {
        return envutil.GetEnvString("MCP_GATEWAY_PAYLOAD_DIR", config.DefaultPayloadDir)
    }
    func getDefaultPayloadPathPrefix() string {
        return envutil.GetEnvString("MCP_GATEWAY_PAYLOAD_PATH_PREFIX", defaultPayloadPathPrefix)
    }
    func getDefaultPayloadSizeThreshold() int {
        return envutil.GetEnvInt("MCP_GATEWAY_PAYLOAD_SIZE_THRESHOLD", config.DefaultPayloadSizeThreshold)
    }

Impact Analysis

• Maintainability: Adding new flags requires adding new one-liner functions; pattern is repetitive
• Bug Risk: Low — each function is trivial and clearly correct
• Code Bloat: ~27 lines of boilerplate for 9 functions that could be replaced by direct os.Getenv() calls at the call site, or by a shared helper

Refactoring Recommendations

1. Inline trivial getters directly at the flag registration call site (since they are only called once):

   // Before
   cmd.Flags().StringVar(&difcSinkServerIDs, "guards-sink-server-ids", getDefaultDIFCSinkServerIDs(), "...")
   
   // After
   cmd.Flags().StringVar(&difcSinkServerIDs, "guards-sink-server-ids", os.Getenv("MCP_GATEWAY_GUARDS_SINK_SERVER_IDS"), "...")

   • Applicable to the 5 trivial os.Getenv() wrappers in flags_difc.go
   • Estimated effort: 15 minutes
   • Benefits: Removes 15+ lines of boilerplate; env var name is visible at the registration site

2. Alternative: Keep as named functions (acceptable if the team values named functions for documentation purposes — they make the flag default source explicit in the code).

   Note: getDefaultDIFCMode() (lines 41–51) is intentionally more complex with validation logic — it should remain as a named function regardless.

Implementation Checklist

• Decide: inline or keep named getters (team preference)
• If inlining: replace 5 trivial os.Getenv() wrappers in flags_difc.go
• If inlining: verify call sites are updated
• Run make test to verify no regressions

Parent Issue

See parent analysis report: #2361
Related to #2361

Generated by Duplicate Code Detector · ◷

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• expires on Mar 30, 2026, 3:05 AM UTC