struct_viewer

The struct_viewer package is a Go library designed to simplify the management and visualization of application configurations using Go structs and environment variables. It allows you to define your configuration as a struct, populate it with values from environment variables, and expose both the configuration and its corresponding environment variables via HTTP endpoints for easy inspection and debugging.

Features

• Parse struct-based configurations.
• Expose configuration fields and environment variables as JSON.
• Simple HTTP handlers to expose config and envs.
• Secure: Automatically obfuscate sensitive data.

Installation

To install the struct_viewer package, use the go get command:

go get -u github.com/TykTechnologies/struct-viewer

Usage

Below is a simple example of how to use struct_viewer in your application:

package main

import (
	"log"
	"net/http"

	"github.com/TykTechnologies/structviewer"
)

type Config struct {
	
	Field1       string `json:"field1"`
	Field2       int    `json:"field2"`

	// This field can be obfuscated with the structviewer tag
	Field3secret string `json:"field3_secret" structviewer:"obfuscate"` 
}

func main() {

	  // Define configuration structure
  	config := &structviewer.Config{
               Object: &YourConfigStruct{
   		       Field1: "value1",
  		       Field2: 123,
   	       },

        }

	// prefix is added to each env var
	v, err := structviewer.New(config, "PREFIX")
	if err != nil {
		panic(err)
	}

	http.HandleFunc("/config", v.JSONHandler)
	http.HandleFunc("/envs", v.EnvsHandler)
	err = http.ListenAndServe(":8080", nil)
	if err != nil {
		log.Fatal("ListenAndServe: ", err)
	}
}

This will expose two endpoints:

• /config: returns a json representation of the config struct.
  • Example: curl -s 'http://localhost:8080/config' | jq .
• /envs: returns a json representation of the environment variables of the config struct. You can pass query parameters env to the endpoints to retrieve specific config fields or specific environment variables.
  • Example:
    • curl -s 'http://localhost:8080/env' | jq .
    • curl -s 'http://localhost:8080/env?env=PREFIX_FIELD1' | jq .

HTTP Handlers

/config: Exposes the entire config object. /detailed-config: Exposes detailed configuration fields with descriptions. /envs: Exposes environment variables mapped from the config object.

Error Handling

The library provides several error types:

ErrNilConfig: Returned when a nil configuration struct is provided. ErrEmptyStruct: Returned when an empty struct is provided. ErrInvalidObjectType: Returned when the object is not of struct type.

Contributing

We welcome contributions! Please see our contribution guidelines for details.

Limitations

• Only exported fields in Go struct are parsed
• Only struct fields can have comments in them
• Single file parsing
• No obfuscation

Contributing

Contributing We welcome contributions! Please see our contribution guidelines for details. If you find any issues or have suggestions for improvement, please open an issue or submit a pull request on GitHub.