https://github.com/gogo/letmegrpc/blob/master/main.go
var mainStr = `package main
import tmpprotos "tmpprotos"
import "google.golang.org/grpc"
func main() {
tmpprotos.Serve("` + *httpAddr + `", "` + *grpcAddr + `",
tmpprotos.DefaultHtmlStringer,
grpc.WithInsecure(), grpc.WithDecompressor(grpc.NewGZIPDecompressor()),
)
}
`
if err := ioutil.WriteFile(filepath.Join(cmdDir, "/main.go"), []byte(mainStr), 0777); err != nil {
log.Fatalf("%s\n", err)
}
gorun := exec.Command("go", "run", "main.go")
envs := os.Environ()
for i, e := range envs {
if strings.HasPrefix(e, "GOPATH") {
envs[i] = envs[i] + ":" + tmpDir
}
}
gorun.Env = envs
gorun.Dir = cmdDir
out, err := gorun.CombinedOutput()
if err != nil {
log.Fatalf("%s %s\n", string(out), err)
}
package main
import (
"bytes"
"fmt"
"go/ast"
"go/parser"
"go/printer"
"go/token"
"testing"
)
func main() {
tests := []testing.InternalTest{{"TestAst", TestAst}}
matchAll := func(t string, pat string) (bool, error) { return true, nil }
testing.Main(matchAll, tests, nil, nil)
}
func TestAst(t *testing.T) {
source := `package a
// B comment
type B struct {
// C comment
C string
}`
fset := token.NewFileSet()
file, err := parser.ParseFile(fset, "", []byte(source), parser.ParseComments)
if err != nil {
t.Error(err)
}
v := &visitor{
file: file,
}
ast.Walk(v, file)
var output []byte
buf := bytes.NewBuffer(output)
if err := printer.Fprint(buf, fset, file); err != nil {
t.Error(err)
}
expected := `package a
// B comment
type B struct {
// C comment
C string
// D comment
D int
// E comment
E float64
}
`
if buf.String() != expected {
t.Error(fmt.Sprintf("Test failed. Expected:\n%s\nGot:\n%s", expected, buf.String()))
}
}
type visitor struct {
file *ast.File
}
func (v *visitor) Visit(node ast.Node) (w ast.Visitor) {
if node == nil {
return v
}
switch n := node.(type) {
case *ast.GenDecl:
if n.Tok != token.TYPE {
break
}
ts := n.Specs[0].(*ast.TypeSpec)
if ts.Name.Name == "B" {
fields := ts.Type.(*ast.StructType).Fields
addStructField(fields, v.file, "int", "D", "D comment")
addStructField(fields, v.file, "float64", "E", "E comment")
}
}
return v
}
func addStructField(fields *ast.FieldList, file *ast.File, typ string, name string, comment string) {
c := &ast.Comment{Text: fmt.Sprint("// ", comment)}
cg := &ast.CommentGroup{List: []*ast.Comment{c}}
f := &ast.Field{
Doc: cg,
Names: []*ast.Ident{ast.NewIdent(name)},
Type: ast.NewIdent(typ),
}
fields.List = append(fields.List, f)
file.Comments = append(file.Comments, cg)
}