Add --config CLI flag to specify custom configuration file path

[badri]

User description

Changes:

• Add flag parsing in cmd/main.go to accept --config parameter
• Modify config.Load() to accept configPath parameter (defaults to "config.json")
• Add comprehensive tests for custom config path functionality
• Update README.md with documentation for --config flag (English and Japanese)

Benefits:

• Support running multiple instances with different configurations
• Enable testing different models or chunk sizes easily
• Allow separate dev/test/prod configurations
• Follow industry standard CLI patterns (docker, kubectl, git, etc.)

Tests added:

• TestLoadConfig_CustomPath: Verify custom config loading
• TestLoadConfig_CustomPath_NotFound: Test fallback to defaults
• TestLoadConfig_CustomPath_InvalidJSON: Test graceful degradation
• TestLoadConfig_RelativeAndAbsolutePaths: Test both path types

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PR Type

Enhancement, Tests

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Description

• Add --config CLI flag to specify custom configuration file path

• Modify config.Load() to accept configPath parameter with defaults

• Add four comprehensive tests for custom config path functionality

• Update README.md with CLI flag documentation (English and Japanese)

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Diagram Walkthrough

flowchart LR
  CLI["CLI Arguments"] -- "--config flag" --> Main["cmd/main.go"]
  Main -- "configPath parameter" --> ConfigLoad["config.Load()"]
  ConfigLoad -- "custom or default path" --> ConfigFile["Configuration File"]
  ConfigFile -- "loaded config" --> App["Application"]

Loading

File Walkthrough

	Relevant files
Enhancement	main.go Add CLI flag parsing for config path                                          cmd/main.go Import flag package for CLI argument parsing Add flag parsing to accept --config parameter with default value config.json Pass parsed configPath to config.Load() function +6/-1      config.go Support dynamic config file path parameter                              internal/config/config.go Modify Load() function signature to accept configPath string parameter Add empty string check to default to config.json if not provided Update all file operations to use dynamic configPath instead of hardcoded constant Only generate template file when using default config.json path Update all log messages to reference the actual config file path +18/-13
Tests	config_test.go Add comprehensive custom config path tests                              internal/config/config_test.go Update existing tests to pass empty string "" to Load() for default behavior Add TestLoadConfig_CustomPath() to verify custom config file loading with various settings Add TestLoadConfig_CustomPath_NotFound() to test fallback to defaults when file missing Add TestLoadConfig_CustomPath_InvalidJSON() to test graceful degradation with invalid JSON Add TestLoadConfig_RelativeAndAbsolutePaths() to verify both relative and absolute path support +155/-2
Documentation	README.md Document --config flag in English and Japanese                      README.md Add English documentation section for --config command-line option with usage example Explain use cases for custom config paths (multiple instances, testing, dev/test/prod separation) Add MCP server configuration example showing --config flag usage Add Japanese translation of command-line options section with equivalent examples and use cases Add Japanese MCP server configuration example with --config flag +54/-0

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[qodo-code-review]

PR Compliance Guide 🔍

Below is a summary of compliance checks for this PR:

Security Compliance
🟢	No security concerns identified No security vulnerabilities detected by AI analysis. Human verification advised for critical code.
Ticket Compliance
⚪	🎫 No ticket provided Create ticket/issue
Codebase Duplication Compliance
⚪	Codebase context is not defined Follow the guide to enable codebase context checks.
Custom Compliance
🟢	Generic: Meaningful Naming and Self-Documenting Code Objective: Ensure all identifiers clearly express their purpose and intent, making code self-documenting Status: Passed
	Generic: Secure Error Handling Objective: To prevent the leakage of sensitive system information through error messages while providing sufficient detail for internal debugging. Status: Passed
⚪	Generic: Comprehensive Audit Trails Objective: To create a detailed and reliable record of critical system actions for security analysis and compliance. Status: Action logging: New config loading paths and outcomes are printed to stderr but there is no structured audit log of critical actions like config file access success/failure or fallback decisions with user/context. Referred Code // Check if config file exists if _, err := os.Stat(configPath); os.IsNotExist(err) { fmt.Fprintf(os.Stderr, "[INFO] %s not found, using defaults\n", configPath) cfg := DefaultConfig() // Only generate template if using default path if configPath == "config.json" { if err := cfg.Save(configPath); err != nil { fmt.Fprintf(os.Stderr, "[WARN] Failed to generate config template: %v\n", err) } else { fmt.Fprintf(os.Stderr, "[INFO] Generated config template: %s\n", configPath) } } return cfg, nil } // Read existing config data, err := os.ReadFile(configPath) if err != nil { return nil, fmt.Errorf("failed to read config: %w", err) ... (clipped 11 lines)
	Generic: Robust Error Handling and Edge Case Management Objective: Ensure comprehensive error handling that provides meaningful context and graceful degradation Status: Fallback handling: The loader falls back to defaults on missing/invalid config and logs warnings, but it returns success without surfacing context to callers and does not validate external input (path) beyond existence, which may obscure configuration issues. Referred Code if _, err := os.Stat(configPath); os.IsNotExist(err) { fmt.Fprintf(os.Stderr, "[INFO] %s not found, using defaults\n", configPath) cfg := DefaultConfig() // Only generate template if using default path if configPath == "config.json" { if err := cfg.Save(configPath); err != nil { fmt.Fprintf(os.Stderr, "[WARN] Failed to generate config template: %v\n", err) } else { fmt.Fprintf(os.Stderr, "[INFO] Generated config template: %s\n", configPath) } } return cfg, nil } // Read existing config data, err := os.ReadFile(configPath) if err != nil { return nil, fmt.Errorf("failed to read config: %w", err) } ... (clipped 7 lines)
	Generic: Secure Logging Practices Objective: To ensure logs are useful for debugging and auditing without exposing sensitive information like PII, PHI, or cardholder data. Status: Unstructured logs: New informational and warning messages are plain text to stderr and include file paths, lacking structured logging and controls to avoid sensitive data exposure in logs. Referred Code fmt.Fprintf(os.Stderr, "[INFO] %s not found, using defaults\n", configPath) cfg := DefaultConfig() // Only generate template if using default path if configPath == "config.json" { if err := cfg.Save(configPath); err != nil { fmt.Fprintf(os.Stderr, "[WARN] Failed to generate config template: %v\n", err) } else { fmt.Fprintf(os.Stderr, "[INFO] Generated config template: %s\n", configPath) } } return cfg, nil } // Read existing config data, err := os.ReadFile(configPath) if err != nil { return nil, fmt.Errorf("failed to read config: %w", err) } ... (clipped 9 lines)
	Generic: Security-First Input Validation and Data Handling Objective: Ensure all data inputs are validated, sanitized, and handled securely to prevent vulnerabilities Status: Path validation: The new configPath input from CLI is used directly without validation or normalization (e.g., path traversal checks, symlink handling, permissions), and errors may reveal filesystem paths in logs. Referred Code func Load(configPath string) (*Config, error) { if configPath == "" { configPath = "config.json" } // Check if config file exists if _, err := os.Stat(configPath); os.IsNotExist(err) { fmt.Fprintf(os.Stderr, "[INFO] %s not found, using defaults\n", configPath) cfg := DefaultConfig() // Only generate template if using default path if configPath == "config.json" { if err := cfg.Save(configPath); err != nil { fmt.Fprintf(os.Stderr, "[WARN] Failed to generate config template: %v\n", err) } else { fmt.Fprintf(os.Stderr, "[INFO] Generated config template: %s\n", configPath) } } return cfg, nil } ... (clipped 5 lines)
Update

Compliance status legend

🟢 - Fully Compliant
🟡 - Partial Compliant
🔴 - Not Compliant
⚪ - Requires Further Human Verification
🏷️ - Compliance label

[qodo-code-review]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
High-level	Fail startup on invalid custom config The application should error and exit if a user-specified configuration file is not found or contains invalid JSON, rather than silently falling back to default settings. This "fail-fast" approach prevents unexpected behavior from running with an unintended configuration. Examples: internal/config/config.go [47-61] if _, err := os.Stat(configPath); os.IsNotExist(err) { fmt.Fprintf(os.Stderr, "[INFO] %s not found, using defaults\n", configPath) cfg := DefaultConfig() // Only generate template if using default path if configPath == "config.json" { if err := cfg.Save(configPath); err != nil { fmt.Fprintf(os.Stderr, "[WARN] Failed to generate config template: %v\n", err) } else { fmt.Fprintf(os.Stderr, "[INFO] Generated config template: %s\n", configPath) ... (clipped 5 lines) internal/config/config.go [70-74] if err := json.Unmarshal(data, cfg); err != nil { fmt.Fprintf(os.Stderr, "[WARN] Invalid JSON in %s: %v\n", configPath, err) fmt.Fprintf(os.Stderr, "[WARN] Using default configuration\n") return cfg, nil } Solution Walkthrough: Before: // in internal/config/config.go func Load(configPath string) (*Config, error) { if _, err := os.Stat(configPath); os.IsNotExist(err) { // If a custom config path is provided and not found... if configPath != "config.json" { // ...it logs and returns default config without an error. return DefaultConfig(), nil } // ... } data, err := os.ReadFile(configPath) // ... cfg := DefaultConfig() if err := json.Unmarshal(data, cfg); err != nil { // If config is invalid JSON, it logs and returns default config. return DefaultConfig(), nil } return cfg, nil } After: // in internal/config/config.go func Load(configPath string) (*Config, error) { if _, err := os.Stat(configPath); os.IsNotExist(err) { // If a custom config path is provided and not found... if configPath != "config.json" { // ...it should return an error. return nil, fmt.Errorf("config file not found: %s", configPath) } // ... } data, err := os.ReadFile(configPath) // ... cfg := DefaultConfig() if err := json.Unmarshal(data, cfg); err != nil { // If config is invalid JSON, it should return an error. return nil, fmt.Errorf("invalid JSON in %s: %w", configPath, err) } return cfg, nil } Suggestion importance[1-10]: 9 __ Why: This suggestion correctly identifies a critical design flaw where providing an invalid custom config path fails silently, which could lead to major operational issues like using the wrong database or model.	High
Possible issue	Fail on invalid JSON configuration When parsing a user-provided configuration file fails due to invalid JSON, the program should exit with an error instead of silently falling back to default settings. internal/config/config.go [70-74] if err := json.Unmarshal(data, cfg); err != nil { - fmt.Fprintf(os.Stderr, "[WARN] Invalid JSON in %s: %v\n", configPath, err) - fmt.Fprintf(os.Stderr, "[WARN] Using default configuration\n") - return cfg, nil + return nil, fmt.Errorf("failed to parse config file %s: %w", configPath, err) } Apply / Chat Suggestion importance[1-10]: 7 __ Why: The suggestion correctly identifies that silently falling back to default settings on an invalid JSON configuration is poor user experience and proposes a "fail-fast" approach, which is more robust.	Medium
General	Generate config template at custom paths Modify the logic to generate a template configuration file at the user-specified path if the file does not exist, instead of only doing so for the default config.json path. internal/config/config.go [51-58] - // Only generate template if using default path - if configPath == "config.json" { - if err := cfg.Save(configPath); err != nil { - fmt.Fprintf(os.Stderr, "[WARN] Failed to generate config template: %v\n", err) - } else { - fmt.Fprintf(os.Stderr, "[INFO] Generated config template: %s\n", configPath) - } + // Attempt to generate a template config file if it doesn't exist. + if err := cfg.Save(configPath); err != nil { + // Log a warning if saving fails, but continue with defaults. + // This handles cases like non-existent directories or permission errors gracefully. + fmt.Fprintf(os.Stderr, "[WARN] Could not write config template to %s: %v\n", configPath, err) + } else { + fmt.Fprintf(os.Stderr, "[INFO] Generated config template: %s\n", configPath) } Apply / Chat Suggestion importance[1-10]: 6 __ Why: The suggestion proposes a valid user experience improvement by creating a template configuration file even at custom paths, which makes the tool's behavior more intuitive and helpful.	Low
Update

[tomohiro-owada]

Thanks for this contribution! The --config flag is a very useful feature that will benefit many users.

There are some merge conflicts with the current main branch, but I'll resolve them on my end after merging. No action needed from you.

Merging now - thank you! 🎉

[tomohiro-owada]

I've resolved the merge conflicts and merged the fix in PR #6. Everything is working now!

Thank you again for your contribution - this feature is a great addition to DevRag. 🙏