generate plugin clients via template

Signed-off-by: Brian Goff <cpuguy83@gmail.com>

plugins/pluginrpc-gen/main.go

@@ -0,0 +1,91 @@
+package main
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"go/format"
+	"io/ioutil"
+	"os"
+	"unicode"
+	"unicode/utf8"
+)
+
+type stringSet struct {
+	values map[string]struct{}
+}
+
+func (s stringSet) String() string {
+	return ""
+}
+
+func (s stringSet) Set(value string) error {
+	s.values[value] = struct{}{}
+	return nil
+}
+func (s stringSet) GetValues() map[string]struct{} {
+	return s.values
+}
+
+var (
+	typeName   = flag.String("type", "", "interface type to generate plugin rpc proxy for")
+	rpcName    = flag.String("name", *typeName, "RPC name, set if different from type")
+	inputFile  = flag.String("i", "", "input file path")
+	outputFile = flag.String("o", *inputFile+"_proxy.go", "output file path")
+
+	skipFuncs   map[string]struct{}
+	flSkipFuncs = stringSet{make(map[string]struct{})}
+
+	flBuildTags = stringSet{make(map[string]struct{})}
+)
+
+func errorOut(msg string, err error) {
+	if err == nil {
+		return
+	}
+	fmt.Fprintf(os.Stderr, "%s: %v\n", msg, err)
+	os.Exit(1)
+}
+
+func checkFlags() error {
+	if *outputFile == "" {
+		return fmt.Errorf("missing required flag `-o`")
+	}
+	if *inputFile == "" {
+		return fmt.Errorf("missing required flag `-i`")
+	}
+	return nil
+}
+
+func main() {
+	flag.Var(flSkipFuncs, "skip", "skip parsing for function")
+	flag.Var(flBuildTags, "tag", "build tags to add to generated files")
+	flag.Parse()
+	skipFuncs = flSkipFuncs.GetValues()
+
+	errorOut("error", checkFlags())
+
+	pkg, err := Parse(*inputFile, *typeName)
+	errorOut(fmt.Sprintf("error parsing requested type %s", *typeName), err)
+
+	var analysis = struct {
+		InterfaceType string
+		RPCName       string
+		BuildTags     map[string]struct{}
+		*parsedPkg
+	}{toLower(*typeName), *rpcName, flBuildTags.GetValues(), pkg}
+	var buf bytes.Buffer
+
+	errorOut("parser error", generatedTempl.Execute(&buf, analysis))
+	src, err := format.Source(buf.Bytes())
+	errorOut("error formating generated source", err)
+	errorOut("error writing file", ioutil.WriteFile(*outputFile, src, 0644))
+}
+
+func toLower(s string) string {
+	if s == "" {
+		return ""
+	}
+	r, n := utf8.DecodeRuneInString(s)
+	return string(unicode.ToLower(r)) + s[n:]
+}