envstruct
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envstruct is a simple library for populating values on structs from environment
variables.
Usage
Export some environment variables.
$ export HOST_IP="127.0.0.1"
$ export HOST_PORT="443"
$ export PASSWORD="abc123"
Note: The environment variables are case
sensitive. The casing of the set environment variable must match the casing in
the struct tag.
Write some code. In this example, IP
requires that the HOST_IP
environment
variable is set to non empty value and Port
defaults to 80
if HOST_PORT
is
an empty value. Then we use the envstruct.WriteReport()
to print a table with
a report of what fields are on the struct, the type, the environment variable
where the value is read from, whether or not it is required, and the value.
All values are omitted by default, if you wish to display the value for a
field you can add report
to the env
struct tag.
package main
import envstruct "code.cloudfoundry.org/go-envstruct"
type Credentials struct {
Username string `json:"username"`
Password string `json:"password"`
}
func (c *Credentials) UnmarshalEnv(data string) error {
return json.Unmarshal([]byte(data), c)
}
type HostInfo struct {
Credentials Credentials `env:"CREDENTIALS, required"`
IP string `env:"HOST_IP, required, report"`
Port int `env:"HOST_PORT, report"`
}
func main() {
hi := HostInfo{Port: 80}
err := envstruct.Load(&hi)
if err != nil {
panic(err)
}
envstruct.WriteReport(&hi)
}
Run your code and rejoice!
$ go run example/example.go
FIELD NAME: TYPE: ENV: REQUIRED: VALUE:
Credentials main.Credentials CREDENTIALS true (OMITTED)
IP string HOST_IP true 10.0.0.1
Port int HOST_PORT false 80
Credentials: {Username:my-user Password:my-password}
Supported Types
- string
- bool (
true
and 1
results in true value, anything else results in false value)
- int
- int8
- int16
- int32
- int64
- uint
- uint8
- uint16
- uint32
- uint64
- float32
- float64
- complex64
- complex128
- []slice (Slices of any other supported type. Environment variable should
have coma separated values)
- time.Duration
- *url.URL
- Struct
- Pointer to Struct
- map[string]string (Environment variable should have comma separated
key:value
. Keys cannot contain colons and neither key nor value can
contain commas. e.g. key_one:value_one, key_two:value_two
- Custom Unmarshaller (see Credentials in example above)
Running Tests
Run tests using ginkgo.
$ go run github.com/onsi/ginkgo/v2/ginkgo -r