66 lines
1.9 KiB
Go
66 lines
1.9 KiB
Go
package mcfg
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import (
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"encoding/json"
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"github.com/mediocregopher/mediocre-go-lib/mcmp"
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)
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// ParamValue describes a value for a parameter which has been parsed by a
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// Source.
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type ParamValue struct {
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Name string
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Path []string
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Value json.RawMessage
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}
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// Source parses ParamValues out of a particular configuration source, given the
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// Component which the Params were added to (via WithInt, WithString, etc...).
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// CollectParams can be used to retrieve these Params.
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//
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// It's possible for Parsing to affect the Component itself, for example in the
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// case of sub-commands.
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//
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// Source should not return ParamValues which were not explicitly set to a value
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// by the configuration source.
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//
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// The returned []ParamValue may contain duplicates of the same Param's value.
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// in which case the latter value takes precedence. It may also contain
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// ParamValues which do not correspond to any of the passed in Params. These
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// will be ignored in Populate.
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type Source interface {
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Parse(*mcmp.Component) ([]ParamValue, error)
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}
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// ParamValues is simply a slice of ParamValue elements, which implements Parse
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// by always returning itself as-is.
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type ParamValues []ParamValue
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var _ Source = ParamValues{}
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// Parse implements the method for the Source interface.
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func (pvs ParamValues) Parse(*mcmp.Component) ([]ParamValue, error) {
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return pvs, nil
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}
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// Sources combines together multiple Source instances into one. It will call
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// Parse on each element individually. Values from later Sources take precedence
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// over previous ones.
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type Sources []Source
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var _ Source = Sources{}
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// Parse implements the method for the Source interface.
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func (ss Sources) Parse(cmp *mcmp.Component) ([]ParamValue, error) {
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var pvs []ParamValue
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for _, s := range ss {
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var innerPVs []ParamValue
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var err error
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if innerPVs, err = s.Parse(cmp); err != nil {
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return nil, err
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}
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pvs = append(pvs, innerPVs...)
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}
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return pvs, nil
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}
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