How to handle configuration in Go

Question

I m new at Go programming  and I m wondering  what is the preferred way to handle configuration parameters for a Go program  the kind of stuff one might use properties files or ini files for  in other contexts

User · Answer

Viper is a golang configuration management system that works with JSON  YAML  and TOML  It looks pretty interesting

User · Answer

I tried JSON   It worked   But I hate having to create the struct of the exact fields and types I might be setting   To me that was a pain   I noticed it was the method used by all the configuration options I could find   Maybe my background in dynamic languages makes me blind to the benefits of such verboseness   I made a new simple config file format  and a more dynamic-ish lib for reading it out  https   github com chrisftw ezconf I am pretty new to the Go world  so it might not be the Go way   But it works  it is pretty quick  and super simple to use  Pros  Super simple Less code  Cons  No Arrays or Map types Very flat file format Non-standard conf files Does have a little convention built-in  which I now if frowned upon in general in Go community   Looks for config file in the config directory

User · Answer

https   github com spf13 viper and https   github com zpatrick go-config are a pretty good libraries for configuration files

User · Answer

I wrote a simple ini config library in golang   https   github com c4pt0r cfg  goroutine-safe  easy to use  package cfg import        testing     func TestCfg t  testing T        c    NewCfg  test ini       if err    c Load     err    nil           t Error err            c WriteInt  hello   42      c WriteString  hello1    World        v  err    c ReadInt  hello   0      if err    nil    v    42           t Error err             v1  err    c ReadString  hello1           if err    nil    v1     World            t Error err             if err    c Save    err    nil           t Error err                               Update                         Recently I need an INI parser with section support  and I write a simple package   github com c4pt0r cfg   u can parse INI like using  flag  package   package main  import        log       github com c4pt0r ini     var conf   ini NewConf  test ini    var       v1   conf String  section1    field1    v1       v2   conf Int  section1    field2   0     func main         conf Parse        log Println  v1   v2

User · Answer

You might also be interested in go-libucl  a set of Go bindings for UCL  the Universal Configuration Language  UCL is a bit like JSON  but with better support for humans  it supports comments and human-readable constructs like SI multipliers  10k  40M  etc   and has a little bit less boilerplate  e g   quotes around keys   It s actually pretty close to the nginx configuration file format  if you re already familiar with that

User · Answer

I have started using Gcfg which uses Ini-like files  It s simple - if you want something simple  this is a good choice   Here s the loading code I am using currently  which has default settings and allows command line flags  not shown  that override some of my config   package util  import        code google com p gcfg     type Config struct       Port int     Verbose bool     AccessLog string     ErrorLog string     DbDriver string     DbConnection string     DbTblPrefix string    type configFile struct       Server Config    const defaultConfig          server      port   8000     verbose   false     accessLog   -     errorLog    -     dbDriver       mysql     dbConnection   testuser TestPasswd9  test     dbTblPrefix       func LoadConfiguration cfgFile string  port int  verbose bool  Config       var err error     var cfg configFile      if cfgFile                 err   gcfg ReadFileInto  amp cfg  cfgFile        else           err   gcfg ReadStringInto  amp cfg  defaultConfig             PanicOnError err       if port    0           cfg Server Port   port           if verbose           cfg Server Verbose   true            return cfg Server

User · Answer

have a look at gonfig     load config       gonfig FromJson myJsonFile     read with defaults host       config GetString  service host    localhost   port       config GetInt  service port   80  test       config GetBool  service testing   false  rate       config GetFloat  service rate   0 0     parse section into target structure config GetAs  service template    amp template

User · Answer

Another option is to use TOML  which is an INI-like format created by Tom Preston-Werner  I built a Go parser for it that is extensively tested  You can use it like other options proposed here  For example  if you have this TOML data in something toml  Age   198 Cats      Cauchy    Plato    Pi   3 14 Perfection     6  28  496  8128   DOB   1987-07-05T05 45 00Z   Then you can load it into your Go program with something like  type Config struct       Age int     Cats   string     Pi float64     Perfection   int     DOB time Time    var conf Config if    err    toml DecodeFile  something toml    amp conf   err    nil          handle error

User · Answer

I agree with nemo and I wrote a little tool to make it all real easy   bitbucket org gotamer cfg is a json configuration package     You define your config items in your application as a struct  A json config file template from your struct is saved on the first run You can save runtime modifications to the config   See doc go for an example

User · Answer

Use toml like this article Reading config files the Go way

User · Answer

The JSON format worked for me quite well  The standard library offers methods to write the data structure indented  so it is quite readable   See also this golang-nuts thread   The benefits of JSON are that it is fairly simple to parse and human readable editable while offering semantics for lists and mappings  which can become quite handy   which is not the case with many ini-type config parsers   Example usage   conf json          Users     UserA   UserB         Groups     GroupA       Program to read the configuration  import        encoding json       os       fmt     type Configuration struct       Users      string     Groups     string    file       os Open  conf json   defer file Close   decoder    json NewDecoder file  configuration    Configuration   err    decoder Decode  amp configuration  if err    nil     fmt Println  error    err    fmt Println configuration Users     output   UserA  UserB

User · Answer

I usually use JSON for more complicated data structures  The downside is that you easily end up with a bunch of code to tell the user where the error was  various edge cases and what not   For base configuration  api keys  port numbers       I ve had very good luck with the gcfg package  It is based on the git config format   From the documentation   Sample config     Comment line  section  name   value   Another comment flag   implicit value for bool is true   Go struct   type Config struct       Section struct               Name string             Flag bool           And the code needed to read it   var cfg Config err    gcfg ReadFileInto  amp cfg   myconfig gcfg     It also supports slice values  so you can allow specifying a key multiple times and other nice features like that

User · Answer

Just use standard go flags with iniflags   Standard go flags have the following benefits    Idiomatic  Easy to use  Flags can be easily added and scattered across arbitrary packages your project uses  Flags have out-of-the-box support for default values and description  Flags provide standard  help  output with default values and description    The only drawback standard go flags have - is management problems when the number of flags used in your app becomes too large   Iniflags elegantly solves this problem  just modify two lines in your main package and it magically gains support for reading flag values from ini file  Flags from ini files can be overriden by passing new values in command-line   See also https   groups google com forum   topic golang-nuts TByzyPgoAQE for details

[go] How to handle configuration in Go

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