72 lines
1.6 KiB
Go
72 lines
1.6 KiB
Go
package config
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import (
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"bytes"
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"fmt"
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"io/ioutil"
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"strings"
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)
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// Funcs is the mapping of built-in functions for configuration.
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var Funcs map[string]InterpolationFunc
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func init() {
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Funcs = map[string]InterpolationFunc{
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"concat": interpolationFuncConcat,
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"file": interpolationFuncFile,
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"lookup": interpolationFuncLookup,
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}
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}
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// interpolationFuncConcat implements the "concat" function that allows
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// strings to be joined together.
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func interpolationFuncConcat(
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vs map[string]string, args ...string) (string, error) {
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var buf bytes.Buffer
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for _, a := range args {
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if _, err := buf.WriteString(a); err != nil {
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return "", err
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}
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}
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return buf.String(), nil
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}
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// interpolationFuncFile implements the "file" function that allows
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// loading contents from a file.
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func interpolationFuncFile(
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vs map[string]string, args ...string) (string, error) {
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if len(args) != 1 {
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return "", fmt.Errorf(
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"file expects 1 arguments, got %d", len(args))
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}
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data, err := ioutil.ReadFile(args[0])
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if err != nil {
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return "", err
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}
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return string(data), nil
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}
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// interpolationFuncLookup implements the "lookup" function that allows
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// dynamic lookups of map types within a Terraform configuration.
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func interpolationFuncLookup(
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vs map[string]string, args ...string) (string, error) {
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if len(args) != 2 {
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return "", fmt.Errorf(
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"lookup expects 2 arguments, got %d", len(args))
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}
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k := fmt.Sprintf("var.%s", strings.Join(args, "."))
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v, ok := vs[k]
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if !ok {
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return "", fmt.Errorf(
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"lookup in '%s' failed to find '%s'",
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args[0], args[1])
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}
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return v, nil
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}
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