60 lines
1.4 KiB
Go
60 lines
1.4 KiB
Go
package config
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import (
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"io"
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"reflect"
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"github.com/FAU-CDI/wisski-distillery/pkg/envreader"
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"github.com/FAU-CDI/wisski-distillery/pkg/stringparser"
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)
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// Unmarshal updates this configuration from the provided [io.Reader].
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//
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// Data is read using the [envreader.ReadAll] method, see the appropriate documentation for the file format.
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//
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// The `env` and `parser` reflect tags of the [Config] struct determine the keys to read from, and the types to expect.
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// When a key is missing, it is set to the default value.
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//
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// See also [stringparser.Parse].
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func (config *Config) Unmarshal(src io.Reader) error {
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// read all the values!
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values, err := envreader.ReadAll(src)
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if err != nil {
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return err
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}
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vConfig := reflect.ValueOf(config).Elem()
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tConfig := vConfig.Type()
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// iterate over the types
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numValues := tConfig.NumField()
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for i := 0; i < numValues; i++ {
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tField := tConfig.Field(i)
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vField := vConfig.FieldByName(tField.Name)
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env := tField.Tag.Get("env")
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dflt := tField.Tag.Get("default")
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parser := tField.Tag.Get("parser")
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// skip it if it isn't loaded!
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if env == "" {
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continue
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}
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// read the value with a default
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value, ok := values[env]
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if !ok || value == "" {
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if dflt == "" {
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continue
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}
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value = dflt
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}
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// parse the value!
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if err := stringparser.Parse(parser, value, vField); err != nil {
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return err
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}
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}
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return nil
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}
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