synthesio / zconfig Goto Github PK

The configuration repository is used to fill the struct from the various configuration sources (cli, env, file, etc).

The error message should describe the shortest cycle detected by their path, so the end-user can know what was wrong exactly. We don't need anything fancy from graph theory, since this is not something that is important once the structure is right. The simpler naive algorithm will do.

Hi team,

After having a closer look at the code and documentation, I realized that the library depends on two non-std libs, based on the godoc link https://godoc.org/github.com/synthesio/zconfig?imports

• github.com/pkg/errors for error handling
• github.com/fatih/structtag for structure tag listing

Would it be possible to get rid of those two dependancies ?

I would like to see a section about other existing tools (go-flags ...) and another one about why we had to write this library (and so not using the existing ones).

It's a common pattern to see this on a library it helps to understand the differences and what can be achieved with the current library

The hook system can be used to extend capabilities and custom behavior.

Is your feature request related to a problem? Please describe.
Right now we have no way to know what provider provided a config. Sometimes when debugging or monitoring purpose it would be interesting to know if a parameter comes from arguments, environment variables or from the default value.

Describe the solution you'd like
I propose to implement something, I will open an PR

Describe alternatives you've considered
Right now, there is no alternative except copy pasting the repository code in an external lib to store the provider information.

Additional context
None

Describe the bug
The environment seems to be parsed before the first call to zconfig.Configure(). This prevent usage of os.Clearenv() or os.Setenv()

To Reproduce*

// /tmp/zconfigbug.go
package main

import (
    "fmt"
    "os"

    "github.com/synthesio/zconfig"
)

func main() {
    os.Clearenv()
    type Container struct {
        Foo string `key:"foo" default:"foo"`
    }   
    var c Container
    _ = zconfig.Configure(&c)
    fmt.Println(c.Foo)
}

FOO="bar" go run zconfigbug.go 
bar

Expected behavior

FOO="bar" go run zconfigbug.go 
foo

Additional context
I use zconfig to setup my applications. The db layer is tested against a docker, witch address is different from the dev environment. dev comes from environment, test is default values.

MYSQL_DSN=root:rootpass@tcp(localhost:3303)/mytable #dev

type DB struct{
*sql.DB
DSN string `key:"dsn" default:"user:password@tcp(localhost:3306)/mytable"`

A simple but comprehensive explanation in the readme wll do.

Hello team,

Thanks for the great work you have done in open sourcing the lib.

I believe that the README could be enhanced however. In the I want to read my configuration from "insert source name here" section, the example is given with github.com/tidwall/gjson. I think it would be easier to understand with the std encoding/json lib.

Right now the tests are present but there is no way to test them locally or directly on github

Describe the bug
In case of circular dependency withing the target of zconfig.Configure, the function is caught in an infinite loop.
This has been detected using gorm.io/gorm.DB v1.22.4

To Reproduce

package main

import (
        "fmt"

        "github.com/synthesio/zconfig"
        "gorm.io/gorm"
)

type Service struct {
        *gorm.DB
}

func main() {
        fmt.Println("start")
        zconfig.Configure(new(Service))
        fmt.Println("done")
}

Expected behavior
We expect zconfig to properly walk through the service, whether it embeds a circular dependency or not.

Both simple examples and more complex demos, so new users can be getting started quickly.