feat(api): adding api server code

templater can be used as a commmand line tool or as an api server.

pkg/templater/main.go

@@ -0,0 +1,89 @@
+package templater
+
+import (
+	"bytes"
+	encjson "encoding/json"
+	"fmt"
+	"os"
+	"text/template"
+
+	"github.com/hashicorp/hcl/v2"
+	"github.com/hashicorp/hcl/v2/hclsyntax"
+	"github.com/zclconf/go-cty/cty"
+	ctyjson "github.com/zclconf/go-cty/cty/json"
+
+	"forge.cadoles.com/pcaseiro/templatefile/pkg/utils"
+)
+
+func ProcessGoTemplate(file string, config []byte) string {
+
+	// The JSON configuration
+	var confData map[string]interface{}
+	var res bytes.Buffer
+
+	err := encjson.Unmarshal(config, &confData)
+	utils.CheckErr(err)
+
+	// Read the template
+	data, err := os.ReadFile(file)
+	utils.CheckErr(err)
+
+	tpl, err := template.New("conf").Parse(string(data))
+	utils.CheckErr(err)
+
+	utils.CheckErr(tpl.Execute(&res, confData))
+
+	return res.String()
+}
+
+func ProcessHCLTemplate(file string, config []byte) string {
+
+	fct, err := os.ReadFile(file)
+	utils.CheckErr(err)
+
+	expr, diags := hclsyntax.ParseTemplate(fct, file, hcl.Pos{Line: 0, Column: 1})
+	utils.CheckDiags(diags)
+
+	// Retrieve values from JSON
+	var varsVal cty.Value
+	ctyType, err := ctyjson.ImpliedType(config)
+	if err != nil {
+		panic(err)
+		/* Maybe one day
+		cexpr, diags := hclsyntax.ParseExpression(config, "", hcl.Pos{Line: 0, Column: 1})
+		if diags.HasErrors() {
+			panic(diags.Error())
+		}
+		varsVal, diags = cexpr.Value(&hcl.EvalContext{})
+		fmt.Println(cexpr.Variables())
+		checkDiags(diags)
+		*/
+	} else {
+		varsVal, err = ctyjson.Unmarshal(config, ctyType)
+		utils.CheckErr(err)
+	}
+
+	ctx := &hcl.EvalContext{
+		Variables: varsVal.AsValueMap(),
+	}
+
+	for n := range ctx.Variables {
+		if !hclsyntax.ValidIdentifier(n) {
+			panic(fmt.Errorf("invalid template variable name %q: must start with a letter, followed by zero or more letters, digits, and underscores", n))
+		}
+	}
+
+	for _, traversal := range expr.Variables() {
+		root := traversal.RootName()
+		if _, ok := ctx.Variables[root]; !ok {
+			panic(fmt.Errorf("vars map does not contain key %q, referenced at %s", root, traversal[0].SourceRange()))
+		}
+	}
+
+	val, diags := expr.Value(ctx)
+	if diags.HasErrors() {
+		panic(diags.Error())
+	}
+
+	return val.AsString()
+}

pkg/utils/main.go

@@ -0,0 +1,17 @@
+package utils
+
+import (
+	"github.com/hashicorp/hcl/v2"
+)
+
+func CheckErr(e error) {
+	if e != nil {
+		panic(e)
+	}
+}
+
+func CheckDiags(diag hcl.Diagnostics) {
+	if diag.HasErrors() {
+		panic(diag.Error())
+	}
+}