A helper to merge structs and maps in Golang. Useful for configuration default values, avoiding messy if-statements.
Also a lovely [comune](http://en.wikipedia.org/wiki/Mergo) (municipality) in the Province of Ancona in the Italian region of Marche.
## Status
It is ready for production use. [It is used in several projects by Docker, Google, The Linux Foundation, VMWare, Shopify, etc](https://github.com/imdario/mergo#mergo-in-the-wild).
Mergo merges same-type structs and maps by setting default values in zero-value fields. Mergo won't merge unexported (private) fields. It will do recursively any exported one. It also won't merge structs inside maps (because they are not addressable using Go reflection).
Also a lovely [comune](http://en.wikipedia.org/wiki/Mergo) (municipality) in the Province of Ancona in the Italian region of Marche.
## Status
It is ready for production use. [It is used in several projects by Docker, Google, The Linux Foundation, VMWare, Shopify, etc](https://github.com/imdario/mergo#mergo-in-the-wild).
### Important note
Please keep in mind that in [0.3.2](//github.com/imdario/mergo/releases/tag/0.3.2) Mergo changed `Merge()`and `Map()` signatures to support [transformers](#transformers). An optional/variadic argument has been added, so it won't break existing code.
Please keep in mind that a problematic PR broke [0.3.9](//github.com/imdario/mergo/releases/tag/0.3.9). I reverted it in [0.3.10](//github.com/imdario/mergo/releases/tag/0.3.10), and I consider it stable but not bug-free. Also, this version adds suppot for go modules.
If you were using Mergo **before** April 6th 2015, please check your project works as intended after updating your local copy with ```go get -u github.com/imdario/mergo```. I apologize for any issue caused by its previous behavior and any future bug that Mergo could cause (I hope it won't!) in existing projects after the change (release 0.2.0).
Keep in mind that in [0.3.2](//github.com/imdario/mergo/releases/tag/0.3.2), Mergo changed `Merge()`and `Map()` signatures to support [transformers](#transformers). I added an optional/variadic argument so that it won't break the existing code.
If you were using Mergo before April 6th, 2015, please check your project works as intended after updating your local copy with ```go get -u github.com/imdario/mergo```. I apologize for any issue caused by its previous behavior and any future bug that Mergo could cause in existing projects after the change (release 0.2.0).
### Donations
If Mergo is useful to you, consider buying me a coffee, a beer or making a monthly donation so I can keep building great free software. :heart_eyes:
If Mergo is useful to you, consider buying me a coffee, a beer, or making a monthly donation to allow me to keep building great free software. :heart_eyes:
<ahref='https://ko-fi.com/B0B58839'target='_blank'><imgheight='36'style='border:0px;height:36px;'src='https://az743702.vo.msecnd.net/cdn/kofi1.png?v=0'border='0'alt='Buy Me a Coffee at ko-fi.com'/></a>
@ -99,7 +110,7 @@ If Mergo is useful to you, consider buying me a coffee, a beer or making a month
## Usage
You can only merge same-type structs with exported fields initialized as zero value of their type and same-types maps. Mergo won't merge unexported (private) fields but will do recursively any exported one. It won't merge empty structs value as [they are not considered zero values](https://golang.org/ref/spec#The_zero_value) either. Also maps will be merged recursively except for structs inside maps (because they are not addressable using Go reflection).
You can only merge same-type structs with exported fields initialized as zero value of their type and same-types maps. Mergo won't merge unexported (private) fields but will do recursively any exported one. It won't merge empty structs value as [they are zero values](https://golang.org/ref/spec#The_zero_value) too. Also, maps will be merged recursively except for structs inside maps (because they are not addressable using Go reflection).
Warning: if you map a struct to map, it won't do it recursively. Don't expect Mergo to map struct members of your struct as `map[string]interface{}`. They will be just assigned as values.
More information and examples in [godoc documentation](http://godoc.org/github.com/imdario/mergo).
A Go (golang) port of the Ruby dotenv project (which loads env vars from a .env file)
From the original Library:
> Storing configuration in the environment is one of the tenets of a twelve-factor app. Anything that is likely to change between deployment environments–such as resource handles for databases or credentials for external services–should be extracted from the code into environment variables.
>
> But it is not always practical to set environment variables on development machines or continuous integration servers where multiple projects are run. Dotenv load variables from a .env file into ENV when the environment is bootstrapped.
It can be used as a library (for loading in env for your own daemons etc) or as a bin command.
There is test coverage and CI for both linuxish and windows environments, but I make no guarantees about the bin version working on windows.
## Installation
As a library
```shell
go get github.com/joho/godotenv
```
or if you want to use it as a bin command
```shell
go get github.com/joho/godotenv/cmd/godotenv
```
## Usage
Add your application configuration to your `.env` file in the root of your project:
```shell
S3_BUCKET=YOURS3BUCKET
SECRET_KEY=YOURSECRETKEYGOESHERE
```
Then in your Go app you can do something like
```go
package main
import (
"github.com/joho/godotenv"
"log"
"os"
)
func main() {
err := godotenv.Load()
if err != nil {
log.Fatal("Error loading .env file")
}
s3Bucket := os.Getenv("S3_BUCKET")
secretKey := os.Getenv("SECRET_KEY")
// now do something with s3 or whatever
}
```
If you're even lazier than that, you can just take advantage of the autoload package which will read in `.env` on import
```go
import _ "github.com/joho/godotenv/autoload"
```
While `.env` in the project root is the default, you don't have to be constrained, both examples below are 100% legit
The original library [dotenv](https://github.com/bkeepers/dotenv) was written by [Brandon Keepers](http://opensoul.org/), and this port was done by [John Barton](https://johnbarton.co/) based off the tests/fixtures in the original library.
CrazyMax
4 years ago