Add outputs.files task to plan

Signed-off-by: Helder Correia <174525+helderco@users.noreply.github.com>

plan/task/outputfile.go

@@ -0,0 +1,63 @@
+package task
+
+import (
+	"context"
+	"fmt"
+	"io/fs"
+	"os"
+
+	"cuelang.org/go/cue"
+	"go.dagger.io/dagger/compiler"
+	"go.dagger.io/dagger/plancontext"
+	"go.dagger.io/dagger/solver"
+)
+
+func init() {
+	Register("OutputFile", func() Task { return &outputFileTask{} })
+}
+
+type outputFileTask struct {
+}
+
+func (c outputFileTask) Run(ctx context.Context, pctx *plancontext.Context, s solver.Solver, v *compiler.Value) (*compiler.Value, error) {
+	var contents []byte
+	var err error
+
+	switch kind := v.Lookup("contents").Kind(); kind {
+	case cue.StringKind:
+		var str string
+		str, err = v.Lookup("contents").String()
+		if err == nil {
+			contents = []byte(str)
+		}
+	case cue.BottomKind:
+		err = fmt.Errorf("contents is not set")
+	default:
+		err = fmt.Errorf("unhandled data type in contents: %s", kind)
+	}
+
+	if err != nil {
+		return nil, err
+	}
+
+	dest, err := v.Lookup("dest").AbsPath()
+	if err != nil {
+		return nil, err
+	}
+
+	perm := fs.FileMode(0644) // default permission
+	if v.Lookup("permissions").Exists() {
+		permissions, err := v.Lookup("permissions").Int64()
+		if err != nil {
+			return nil, err
+		}
+		perm = fs.FileMode(permissions)
+	}
+
+	err = os.WriteFile(dest, contents, perm)
+	if err != nil {
+		return nil, err
+	}
+
+	return compiler.NewValue(), nil
+}