feat: add templating to copy mapping

dot_test.go

@@ -6,6 +6,7 @@ import (
 	"gopkg.in/yaml.v3"
 	"os"
 	"testing"
+	"runtime"
 )
 
 func isSymlink(path string) bool {
@@ -72,6 +73,27 @@ func TestDoCopy(t *testing.T) {
 	toContents, err = os.ReadFile(m.To)
 	assert.Nil(t, err)
 	assert.Equal(t, fromContents, toContents)
+
+	// copies a file with template
+	m = FileMapping{
+		From: "fixtures/gpg-agent.conf.input",
+		To:   "out/gpg-agent.conf",
+		With: map[string]string {
+			"PinentryPath": "/foo/bar",
+		},
+	}
+
+	err = m.doCopy()
+	assert.Nil(t, err)
+	assert.False(t, isSymlink(m.To))
+
+	// correct contents
+
+	fromContents, err = os.ReadFile("fixtures/gpg-agent.conf.output")
+	assert.Nil(t, err)
+	toContents, err = os.ReadFile(m.To)
+	assert.Nil(t, err)
+	assert.Equal(t, fromContents, toContents)
 }
 
 func TestUnmap(t *testing.T) {
@@ -341,3 +363,31 @@ func TestGetHomeDir(t *testing.T) {
 		assert.Equal(t, got, want)
 	}
 }
+
+func TestEvalTemplateString(t *testing.T) {
+	cases := map[string]string {
+		"{{ .v1 }}": "a value",
+		"{{ .v2 }}": "<no value>",
+	}
+	env := map[string]string {
+		"v1": "a value",
+	}
+	for templ, want := range cases {
+		got := evalTemplateString(templ, env)
+		assert.Equal(t, want, got)
+	}
+}
+
+func TestEvalTemplate(t *testing.T) {
+	curOs := runtime.GOOS
+	with := map[string]string {
+		"t1": "{{if eq .Os \"" + curOs + "\"}}it works{{end}}",
+		"t2": "{{if eq .Os \"linux\"}}must not be this{{end}}",
+		"t3": "{{if eq .Os \"linux\"}}must not be this{{else}}else{{end}}",
+	}
+
+	res := evalTemplate(with)
+	assert.Equal(t, "it works", res["t1"])
+	assert.Equal(t, "", res["t2"], "")
+	assert.Equal(t, "else", res["t3"])
+}

examples/04-dots-copy-templating.yml

@@ -0,0 +1,20 @@
+# to, os, as
+
+map:
+  gitconfig:
+    to: out/gitconfig
+    os: all # all, linux, macos
+  zshrc:
+    to: out/zshrc
+    as: copy
+    os: linux
+  gpg-agent.conf:
+    to: out/gpg-agent.conf
+    as: copy
+    os: macos
+    with:
+      PinentryPath: '{{if eq .Os "darwin"}}/opt/homebrew/bin{{else}}/usr/bin{{end}}'
+
+opt:
+  cd: examples/
+

examples/gpg-agent.conf

@@ -0,0 +1,4 @@
+default-cache-ttl 1800
+max-cache-ttl 3600
+enable-ssh-support
+pinentry-program {{ .PinentryPath }}/pinentry-tty

fixtures/gpg-agent.conf.input

@@ -0,0 +1,4 @@
+default-cache-ttl 1800
+max-cache-ttl 3600
+enable-ssh-support
+pinentry-program {{ .PinentryPath }}/pinentry-tty

fixtures/gpg-agent.conf.output

@@ -0,0 +1,4 @@
+default-cache-ttl 1800
+max-cache-ttl 3600
+enable-ssh-support
+pinentry-program /foo/bar/pinentry-tty

main.go

@@ -13,6 +13,7 @@ import (
 
 	goversion "github.com/caarlos0/go-version"
 	"gopkg.in/yaml.v3"
+	"text/template"
 )
 
 /*
@@ -81,6 +82,7 @@ type FileMapping struct {
 	To   string
 	As   string
 	Os   string
+	With map[string]string
 }
 
 func (m FileMapping) doLink() error {
@@ -92,19 +94,32 @@ func (m FileMapping) doLink() error {
 }
 
 func (m FileMapping) doCopy() error {
-	fin, err := os.Open(m.From)
-	if err != nil {
-		return err
+	var inReader io.Reader
+	if len(m.With) > 0 {
+		for v, m := range m.With {
+			logger.Printf("%s %s\n", v, m)
+		}
+		in, err := os.ReadFile(m.From)
+		if err != nil {
+			panic(err)
+		}
+		inReader = strings.NewReader(evalTemplateString(string(in), m.With))
+	} else {
+		fin, err := os.Open(m.From)
+		if err != nil {
+			return err
+		}
+		defer fin.Close()
+		inReader = fin
 	}
-	defer fin.Close()
 
 	fout, err := os.Create(m.To)
 	if err != nil {
 		return err
 	}
 	defer fout.Close()
 
-	_, err = io.Copy(fout, fin)
+	_, err = io.Copy(fout, inReader)
 	if err != nil {
 		return err
 	}
@@ -196,6 +211,10 @@ func (dots Dots) validate() []error {
 		} else if isDirectory(mapping.From) && mapping.As == "copy" {
 			errs = append(errs, fmt.Errorf("%s: cannot use copy type with directory", mapping.From))
 		}
+
+		if mapping.As != "copy" && len(mapping.With) > 0 {
+			errs = append(errs, fmt.Errorf("%s: templating is only supported in `copy` mode ]", mapping.From));
+		}
 	}
 	return errs
 }
@@ -208,6 +227,28 @@ func inferDestination(file string) string {
 	}
 }
 
+func evalTemplateString(templStr string, env map[string]string) string {
+	templ, err := template.New("template").Parse(templStr)
+	if err != nil {
+		logger.Fatalf("failed creating template from %s, %v", templStr, err)
+	}
+	var templOut bytes.Buffer
+	err = templ.Execute(&templOut, env)
+	if err != nil {
+		logger.Fatalf("failed executing template, %v", err)
+	}
+	return templOut.String()
+}
+
+func evalTemplate(with map[string]string) map[string]string {
+	newMap := make(map[string]string, len(with))
+	for variable, templ := range with {
+		env := map[string]string{ "Os": runtime.GOOS }
+		newMap[variable] = evalTemplateString(templ, env)
+	}
+	return newMap
+}
+
 func (dots Dots) transform() Dots {
 	opts := dots.Opts
 	mappings := dots.FileMappings
@@ -226,6 +267,10 @@ func (dots Dots) transform() Dots {
 			mapping.To = inferDestination(mapping.From)
 		}
 
+		if len(mapping.With) > 0 {
+			mapping.With = evalTemplate(mapping.With)
+		}
+
 		if len(opts.Cd) > 0 {
 			// Cd set: add prefix to From
 			mapping.From = path.Join(opts.Cd, mapping.From)