Add reverse proxy boilerplate with configuration management

- Introduced the main entry point `main.go` with basic configuration loading and error handling.
- Added `config` package to handle environment variables, help printing, and default settings.
- Configured required dependencies in `go.mod` and included their checksums in `go.sum`.
- Created `.gitignore` file for common Go development scenarios.
This commit is contained in:
2025-08-19 16:45:48 +01:00
parent 66c06e063e
commit aba3909038
5 changed files with 387 additions and 0 deletions

110
.gitignore vendored Normal file
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# Allowlisting gitignore template for GO projects prevents us
# from adding various unwanted local files, such as generated
# files, developer configurations or IDE-specific files etc.
#
# Recommended: Go.AllowList.gitignore
# Ignore everything
*
# Especially these
.vscode
.vscode/
.vscode/**
**/.vscode
**/.vscode/**
node_modules
node_modules/
node_modules/**
**/node_modules
**/node_modules/
**/node_modules/**
/test*
.idea
.idea/
.idea/**
/.idea/
/.idea/**
/.idea
# and others
/go.work.sum
/secp256k1/
# But not these files...
!/.gitignore
!*.go
!go.sum
!go.mod
!*.md
!LICENSE
!*.sh
!Makefile
!*.json
!*.pdf
!*.csv
!*.py
!*.mediawiki
!*.did
!*.rs
!*.toml
!*.file
!.gitkeep
!pkg/eth/**
!*.h
!*.c
!*.proto
!bundleData
!*.item
!*.bin
!*.yml
!*.yaml
!*.tmpl
!*.s
!*.asm
!.gitmodules
!*.txt
!*.sum
!pkg/version
!*.service
!*.benc
!*.png
!*.adoc
!*.js
!*.bash
!PATENTS
!*.css
!*.ts
!*.html
!Dockerfile
!*.lock
!*.nix
!license
!readme
!*.ico
!.idea/*
!*.xml
!.name
!.gitignore
!version
!out.jsonl
# ...even if they are in subdirectories
!*/
/blocklist.json
/gui/gui/main.wasm
/gui/gui/index.html
pkg/database/testrealy
/.idea/workspace.xml
/.idea/dictionaries/project.xml
/.idea/shelf/Add_tombstone_handling__enhance_event_ID_logic__update_imports.xml
/.idea/.gitignore
/.idea/misc.xml
/.idea/modules.xml
/.idea/orly.dev.iml
/.idea/vcs.xml
/.idea/codeStyles/codeStyleConfig.xml
/.idea/material_theme_project_new.xml
/.idea/orly.iml
/.idea/go.imports.xml
/.idea/inspectionProfiles/Project_Default.xml
/.idea/.name
/.idea/reverse.iml

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config/config.go Normal file
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package config
import (
"fmt"
"io"
"os"
"reflect"
"sort"
"strings"
"time"
"github.com/mleku/lol/chk"
"go-simpler.org/env"
)
type C struct {
LogLevel string `env:"REVERSE_LOG_LEVEL" default:"info" usage:"Log level: fatal error warn info debug trace"`
Listen string `env:"REVERSE_LISTEN" usage:"Listen address for reverse proxy" default:":443"`
Mapping string `env:"REVERSE_MAPPING" usage:"file containing domain/target mappings for reverse proxy" default:"~/.config/reverse/mapping.conf"`
Cache string `env:"REVERSE_CERTCACHE" usage:"directory where certificates from letsencrypt are stored" default:"~/.cache/reverse"`
HSTS bool `env:"REVERSE_HSTS" usage:"add Strict-TransportSecurity header" default:"false"`
Email string `env:"REVERSE_EMAIL" usage:"email address presented to letsencrypt CA"`
HTTP string `env:"REVERSE_HTTP" usage:"http address for HTTP->HTTPS upgrades" default:":80"`
Idle time.Duration `env:"REVERSE_IDLE" usage:"how long idle connection is kept before closing" default:"1m"`
}
func New() (cfg *C, err error) {
cfg = new(C)
if err = env.Load(cfg, &env.Options{SliceSep: ","}); chk.T(err) {
return
}
if GetEnv() {
PrintEnv(cfg, os.Stdout)
os.Exit(0)
}
if HelpRequested() {
PrintHelp(cfg, os.Stderr)
os.Exit(0)
}
return
}
// HelpRequested determines if the command line arguments indicate a request for help
//
// # Return Values
//
// - help: A boolean value indicating true if a help flag was detected in the
// command line arguments, false otherwise
//
// # Expected Behaviour
//
// The function checks the first command line argument for common help flags and
// returns true if any of them are present. Returns false if no help flag is found
func HelpRequested() (help bool) {
if len(os.Args) > 1 {
switch strings.ToLower(os.Args[1]) {
case "help", "-h", "--h", "-help", "--help", "?":
help = true
}
}
return
}
// GetEnv checks if the first command line argument is "env" and returns
// whether the environment configuration should be printed.
//
// # Return Values
//
// - requested: A boolean indicating true if the 'env' argument was
// provided, false otherwise.
//
// # Expected Behaviour
//
// The function returns true when the first command line argument is "env"
// (case-insensitive), signalling that the environment configuration should be
// printed. Otherwise, it returns false.
func GetEnv() (requested bool) {
if len(os.Args) > 1 {
switch strings.ToLower(os.Args[1]) {
case "env":
requested = true
}
}
return
}
// KV is a key/value pair.
type KV struct{ Key, Value string }
// KVSlice is a sortable slice of key/value pairs, designed for managing
// configuration data and enabling operations like merging and sorting based on
// keys.
type KVSlice []KV
func (kv KVSlice) Len() int { return len(kv) }
func (kv KVSlice) Less(i, j int) bool { return kv[i].Key < kv[j].Key }
func (kv KVSlice) Swap(i, j int) { kv[i], kv[j] = kv[j], kv[i] }
// Compose merges two KVSlice instances into a new slice where key-value pairs
// from the second slice override any duplicate keys from the first slice.
//
// # Parameters
//
// - kv2: The second KVSlice whose entries will be merged with the receiver.
//
// # Return Values
//
// - out: A new KVSlice containing all entries from both slices, with keys
// from kv2 taking precedence over keys from the receiver.
//
// # Expected Behaviour
//
// The method returns a new KVSlice that combines the contents of the receiver
// and kv2. If any key exists in both slices, the value from kv2 is used. The
// resulting slice remains sorted by keys as per the KVSlice implementation.
func (kv KVSlice) Compose(kv2 KVSlice) (out KVSlice) {
// duplicate the initial KVSlice
for _, p := range kv {
out = append(out, p)
}
out:
for i, p := range kv2 {
for j, q := range out {
// if the key is repeated, replace the value
if p.Key == q.Key {
out[j].Value = kv2[i].Value
continue out
}
}
out = append(out, p)
}
return
}
// EnvKV generates key/value pairs from a configuration object's struct tags
//
// # Parameters
//
// - cfg: A configuration object whose struct fields are processed for env tags
//
// # Return Values
//
// - m: A KVSlice containing key/value pairs derived from the config's env tags
//
// # Expected Behaviour
//
// Processes each field of the config object, extracting values tagged with
// "env" and converting them to strings. Skips fields without an "env" tag.
// Handles various value types including strings, integers, booleans, durations,
// and string slices by joining elements with commas.
func EnvKV(cfg any) (m KVSlice) {
t := reflect.TypeOf(cfg)
for i := 0; i < t.NumField(); i++ {
k := t.Field(i).Tag.Get("env")
v := reflect.ValueOf(cfg).Field(i).Interface()
var val string
switch v.(type) {
case string:
val = v.(string)
case int, bool, time.Duration:
val = fmt.Sprint(v)
case []string:
arr := v.([]string)
if len(arr) > 0 {
val = strings.Join(arr, ",")
}
}
// this can happen with embedded structs
if k == "" {
continue
}
m = append(m, KV{k, val})
}
return
}
// PrintEnv outputs sorted environment key/value pairs from a configuration object
// to the provided writer
//
// # Parameters
//
// - cfg: Pointer to the configuration object containing env tags
//
// - printer: Destination for the output, typically an io.Writer implementation
//
// # Expected Behaviour
//
// Outputs each environment variable derived from the config's struct tags in
// sorted order, formatted as "key=value\n" to the specified writer
func PrintEnv(cfg *C, printer io.Writer) {
kvs := EnvKV(*cfg)
sort.Sort(kvs)
for _, v := range kvs {
_, _ = fmt.Fprintf(printer, "%s=%s\n", v.Key, v.Value)
}
}
// PrintHelp prints help information including application version, environment
// variable configuration, and details about .env file handling to the provided
// writer
//
// # Parameters
//
// - cfg: Configuration object containing app name and config directory path
//
// - printer: Output destination for the help text
//
// # Expected Behaviour
//
// Prints application name and version followed by environment variable
// configuration details, explains .env file behaviour including automatic
// loading and custom path options, and displays current configuration values
// using PrintEnv. Outputs all information to the specified writer
func PrintHelp(cfg *C, printer io.Writer) {
_, _ = fmt.Fprintf(printer, "reverse usage:\n\n")
env.Usage(cfg, printer, &env.Options{SliceSep: ","})
_, _ = fmt.Fprintf(
printer,
"\nCLI parameter 'help' also prints this information\n"+
"use the parameter 'env' to print out the current configuration to the terminal\n\n",
)
_, _ = fmt.Fprintf(printer, "current configuration:\n\n")
PrintEnv(cfg, printer)
return
}

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go.mod Normal file
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module github.com/mleku/reverse
go 1.25.0
require (
github.com/mleku/lol v1.0.1
go-simpler.org/env v0.12.0
)
require (
github.com/davecgh/go-spew v1.1.1 // indirect
github.com/fatih/color v1.18.0 // indirect
github.com/mattn/go-colorable v0.1.14 // indirect
github.com/mattn/go-isatty v0.0.20 // indirect
golang.org/x/sys v0.35.0 // indirect
)

15
go.sum Normal file
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github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/fatih/color v1.18.0 h1:S8gINlzdQ840/4pfAwic/ZE0djQEH3wM94VfqLTZcOM=
github.com/fatih/color v1.18.0/go.mod h1:4FelSpRwEGDpQ12mAdzqdOukCy4u8WUtOY6lkT/6HfU=
github.com/mattn/go-colorable v0.1.14 h1:9A9LHSqF/7dyVVX6g0U9cwm9pG3kP9gSzcuIPHPsaIE=
github.com/mattn/go-colorable v0.1.14/go.mod h1:6LmQG8QLFO4G5z1gPvYEzlUgJ2wF+stgPZH1UqBm1s8=
github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
github.com/mleku/lol v1.0.1 h1:CMGpeMTh2iE7Xc4/dtJxs0vZqwRmPiGxsqpWxdmOZKc=
github.com/mleku/lol v1.0.1/go.mod h1:daW3rL0XP4ZKscvWn990AJCrJs2Lsu+sdrI9cWbacWE=
go-simpler.org/env v0.12.0 h1:kt/lBts0J1kjWJAnB740goNdvwNxt5emhYngL0Fzufs=
go-simpler.org/env v0.12.0/go.mod h1:cc/5Md9JCUM7LVLtN0HYjPTDcI3Q8TDaPlNTAlDU+WI=
golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.35.0 h1:vz1N37gP5bs89s7He8XuIYXpyY0+QlsKmzipCbUtyxI=
golang.org/x/sys v0.35.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=

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main.go Normal file
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package main
import (
"fmt"
"os"
"github.com/mleku/lol/chk"
"github.com/mleku/reverse/config"
)
func main() {
var err error
var cfg *config.C
if cfg, err = config.New(); chk.T(err) {
if err != nil {
fmt.Fprintf(os.Stderr, "ERROR: %s\n\n", err)
}
config.PrintHelp(cfg, os.Stderr)
os.Exit(0)
}
}