opentelemetry

OpenTelemetry Package

This package provides OpenTelemetry integration for the LerianStudio commons library, including advanced struct obfuscation capabilities for secure telemetry data.

Features

• OpenTelemetry Integration: Complete setup and configuration for tracing, metrics, and logging
• Struct Obfuscation: Advanced field obfuscation for sensitive data in telemetry spans
• Flexible Configuration: Support for custom obfuscation rules and business logic
• Backward Compatibility: Maintains existing API while adding new security features

Quick Start

Basic Usage (Without Obfuscation)

import (
    "github.com/LerianStudio/lib-commons/commons/opentelemetry"
    "go.opentelemetry.io/otel"
)

// Create a span and add struct data
tracer := otel.Tracer("my-service")
_, span := tracer.Start(ctx, "operation")
defer span.End()

// Add struct data to span (original behavior)
err := opentelemetry.SetSpanAttributesFromStruct(&span, "user_data", userStruct)

With Default Obfuscation

// Create default obfuscator (covers common sensitive fields)
obfuscator := opentelemetry.NewDefaultObfuscator()

// Add obfuscated struct data to span
err := opentelemetry.SetSpanAttributesFromStructWithObfuscation(
    &span, "user_data", userStruct, obfuscator)

With Custom Obfuscation

// Define custom sensitive fields
customFields := []string{"email", "phone", "address"}
customObfuscator := opentelemetry.NewCustomObfuscator(customFields)

// Apply custom obfuscation
err := opentelemetry.SetSpanAttributesFromStructWithObfuscation(
    &span, "user_data", userStruct, customObfuscator)

Struct Obfuscation Examples

Example Data Structure

type UserLoginRequest struct {
    Username    string          `json:"username"`
    Password    string          `json:"password"`
    Email       string          `json:"email"`
    RememberMe  bool            `json:"rememberMe"`
    DeviceInfo  DeviceInfo      `json:"deviceInfo"`
    Credentials AuthCredentials `json:"credentials"`
    Metadata    map[string]any  `json:"metadata"`
}

type DeviceInfo struct {
    UserAgent    string `json:"userAgent"`
    IPAddress    string `json:"ipAddress"`
    DeviceID     string `json:"deviceId"`
    SessionToken string `json:"token"` // Will be obfuscated
}

type AuthCredentials struct {
    APIKey       string `json:"apikey"`        // Will be obfuscated
    RefreshToken string `json:"refresh_token"` // Will be obfuscated
    ClientSecret string `json:"secret"`        // Will be obfuscated
}

Example 1: Default Obfuscation

loginRequest := UserLoginRequest{
    Username:   "john.doe",
    Password:   "super_secret_password_123",
    Email:      "john.doe@example.com",
    RememberMe: true,
    DeviceInfo: DeviceInfo{
        UserAgent:    "Mozilla/5.0...",
        IPAddress:    "192.168.1.100",
        DeviceID:     "device_12345",
        SessionToken: "session_token_abc123xyz",
    },
    Credentials: AuthCredentials{
        APIKey:       "api_key_secret_789",
        RefreshToken: "refresh_token_xyz456",
        ClientSecret: "client_secret_ultra_secure",
    },
    Metadata: map[string]any{
        "theme":       "dark",
        "language":    "en-US",
        "private_key": "private_key_should_be_hidden",
        "public_info": "this is safe to show",
    },
}

// Apply default obfuscation
defaultObfuscator := opentelemetry.NewDefaultObfuscator()
err := opentelemetry.SetSpanAttributesFromStructWithObfuscation(
    &span, "login_request", loginRequest, defaultObfuscator)

// Result: password, token, secret, apikey, private_key fields become "***"

Example 2: Custom Field Selection

// Only obfuscate specific fields
customFields := []string{"username", "email", "deviceId", "ipAddress"}
customObfuscator := opentelemetry.NewCustomObfuscator(customFields)

err := opentelemetry.SetSpanAttributesFromStructWithObfuscation(
    &span, "login_request", loginRequest, customObfuscator)

// Result: Only username, email, deviceId, ipAddress become "***"

Example 3: Custom Business Logic Obfuscator

// Implement custom obfuscation logic
type BusinessLogicObfuscator struct {
    companyPolicy map[string]bool
}

func (b *BusinessLogicObfuscator) ShouldObfuscate(fieldName string) bool {
    return b.companyPolicy[strings.ToLower(fieldName)]
}

func (b *BusinessLogicObfuscator) GetObfuscatedValue() string {
    return "[COMPANY_POLICY_REDACTED]"
}

// Use custom obfuscator
businessObfuscator := &BusinessLogicObfuscator{
    companyPolicy: map[string]bool{
        "email":      true,
        "ipaddress":  true,
        "deviceinfo": true, // Obfuscates entire nested object
    },
}

err := opentelemetry.SetSpanAttributesFromStructWithObfuscation(
    &span, "login_request", loginRequest, businessObfuscator)

Example 4: Standalone Obfuscation Utility

// Use obfuscation without OpenTelemetry spans
obfuscator := opentelemetry.NewDefaultObfuscator()
obfuscatedData, err := opentelemetry.ObfuscateStruct(loginRequest, obfuscator)
if err != nil {
    log.Printf("Obfuscation failed: %v", err)
}

// obfuscatedData now contains the struct with sensitive fields replaced

Default Sensitive Fields

The NewDefaultObfuscator() uses a shared list of sensitive field names from the commons/security package, ensuring consistent obfuscation behavior across HTTP logging, OpenTelemetry spans, and other components.

The following common sensitive field names are automatically obfuscated (case-insensitive):

Authentication & Security

• password
• token
• secret
• key
• authorization
• auth
• credential
• credentials
• apikey
• api_key
• access_token
• refresh_token
• private_key
• privatekey

Note: This list is shared with HTTP logging middleware and other components via security.DefaultSensitiveFields to ensure consistent behavior across the entire commons library.

API Reference

Core Functions

SetSpanAttributesFromStruct(span *trace.Span, key string, valueStruct any) error

Original function for backward compatibility. Adds struct data to span without obfuscation.

SetSpanAttributesFromStructWithObfuscation(span *trace.Span, key string, valueStruct any, obfuscator FieldObfuscator) error

Enhanced function that applies obfuscation before adding struct data to span. If obfuscator is nil, behaves like the original function.

ObfuscateStruct(valueStruct any, obfuscator FieldObfuscator) (any, error)

Standalone utility function that obfuscates a struct and returns the result. Can be used independently of OpenTelemetry spans.

Obfuscator Constructors

NewDefaultObfuscator() *DefaultObfuscator

Creates an obfuscator with predefined common sensitive field names.

NewCustomObfuscator(sensitiveFields []string) *DefaultObfuscator

Creates an obfuscator with custom sensitive field names. Field matching is case-insensitive.

Interface

FieldObfuscator

type FieldObfuscator interface {
    // ShouldObfuscate returns true if the given field name should be obfuscated
    ShouldObfuscate(fieldName string) bool
    // GetObfuscatedValue returns the value to use for obfuscated fields
    GetObfuscatedValue() string
}

Constants

ObfuscatedValue = "***"

Default value used to replace sensitive fields. Can be referenced for consistency.

Advanced Features

Recursive Obfuscation

The obfuscation system works recursively on:

• Nested structs: Processes all nested object fields
• Arrays and slices: Processes each element in collections
• Maps: Processes all key-value pairs

Case-Insensitive Matching

Field name matching is case-insensitive for flexibility:

// All these variations will be obfuscated if "password" is in the sensitive list
"password", "Password", "PASSWORD", "PaSsWoRd"

Performance Considerations

• Efficient processing: Uses pre-allocated maps for field lookups
• Memory conscious: Minimal allocations during recursive processing
• JSON conversion: Leverages Go's efficient JSON marshaling/unmarshaling

Best Practices

Security

• Always use obfuscation for production telemetry data
• Review sensitive field lists regularly to ensure comprehensive coverage
• Implement custom obfuscators for business-specific sensitive data
• Test obfuscation rules to verify sensitive data is properly hidden

Performance

• Reuse obfuscator instances instead of creating new ones for each call
• Use appropriate obfuscation level - don't over-obfuscate if not needed
• Consider caching obfuscated results for frequently used structs

Maintainability

• Use NewDefaultObfuscator() for most common use cases
• Document custom obfuscation rules in your business logic
• Centralize obfuscation policies for consistency across services
• Test obfuscation behavior in your unit tests

Migration

• Backward compatibility: Existing code using SetSpanAttributesFromStruct() continues to work
• Gradual adoption: Add obfuscation incrementally to existing telemetry code
• Monitoring: Verify obfuscated telemetry data meets security requirements

Error Handling

The obfuscation functions return errors in these cases:

• Invalid JSON: When the input struct cannot be marshaled to JSON
• Malformed data: When JSON unmarshaling fails during processing

err := opentelemetry.SetSpanAttributesFromStructWithObfuscation(
    &span, "data", invalidStruct, obfuscator)
if err != nil {
    log.Printf("Obfuscation failed: %v", err)
    // Handle error appropriately
}

Testing

The package includes comprehensive tests covering:

• Default obfuscator behavior
• Custom obfuscator functionality
• Recursive obfuscation of nested structures
• Error handling for invalid data
• Integration with OpenTelemetry spans
• Custom obfuscator interface implementations

Run tests with:

go test ./commons/opentelemetry -v

Examples

For complete working examples, see:

• obfuscation_test.go - Comprehensive test cases
• examples/opentelemetry_obfuscation_example.go - Runnable example application

Contributing

When adding new features:

1. Follow the interface pattern for extensibility
2. Add comprehensive tests for new functionality
3. Update documentation with examples
4. Maintain backward compatibility with existing APIs
5. Follow Go best practices and the project's coding standards