111 lines
2.4 KiB
Go
111 lines
2.4 KiB
Go
package main
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import (
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encjson "encoding/json"
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"fmt"
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"os"
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"text/template"
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"github.com/hashicorp/hcl/v2"
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"github.com/hashicorp/hcl/v2/hclsyntax"
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"github.com/zclconf/go-cty/cty"
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ctyjson "github.com/zclconf/go-cty/cty/json"
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)
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func checkErr(e error) {
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if e != nil {
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panic(e)
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}
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}
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func checkDiags(diag hcl.Diagnostics) {
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if diag.HasErrors() {
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panic(diag.Error())
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}
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}
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func processGoTemplate(file string, config []byte) {
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// The JSON configuration
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var confData map[string]interface{}
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err := encjson.Unmarshal(config, &confData)
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checkErr(err)
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// Read the template
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data, err := os.ReadFile(file)
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checkErr(err)
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tpl, err := template.New("conf").Parse(string(data))
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checkErr(err)
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checkErr(tpl.Execute(os.Stdout, confData))
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}
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func processHCLTemplate(file string, config []byte) {
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fct, err := os.ReadFile(file)
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checkErr(err)
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expr, diags := hclsyntax.ParseTemplate(fct, file, hcl.Pos{Line: 1, Column: 1})
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checkDiags(diags)
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// Retrieve values from JSON
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var varsVal cty.Value
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ctyType, err := ctyjson.ImpliedType(config)
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if err != nil {
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panic(err)
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/* Maybe one day
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cexpr, diags := hclsyntax.ParseExpression(config, "", hcl.Pos{Line: 1, Column: 1})
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if diags.HasErrors() {
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panic(diags.Error())
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}
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varsVal, diags = cexpr.Value(&hcl.EvalContext{})
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fmt.Println(cexpr.Variables())
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checkDiags(diags)
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*/
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} else {
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varsVal, err = ctyjson.Unmarshal(config, ctyType)
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checkErr(err)
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}
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ctx := &hcl.EvalContext{
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Variables: varsVal.AsValueMap(),
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}
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for n := range ctx.Variables {
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if !hclsyntax.ValidIdentifier(n) {
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panic(fmt.Errorf("invalid template variable name %q: must start with a letter, followed by zero or more letters, digits, and underscores", n))
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}
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}
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for _, traversal := range expr.Variables() {
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root := traversal.RootName()
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if _, ok := ctx.Variables[root]; !ok {
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panic(fmt.Errorf("vars map does not contain key %q, referenced at %s", root, traversal[0].SourceRange()))
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}
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}
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val, diags := expr.Value(ctx)
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if diags.HasErrors() {
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panic(diags.Error())
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}
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fmt.Printf("%s", val.AsString())
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}
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func main() {
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// The template to process
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templateType := os.Args[1]
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templateFile := os.Args[2]
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config := []byte(os.Args[3])
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if templateType == "go" {
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processGoTemplate(templateFile, config)
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} else if templateType == "hcl" {
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processHCLTemplate(templateFile, config)
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} else {
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panic(fmt.Errorf("Unsupported template type"))
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}
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}
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