c6937b0bfc
This fix expose directives in dnsserver package, so that external
plugin developers could easily build customerized coredns+plugin
without changing the code base tree of coredns.
The following is an example that could bundle coredns+example,
in one simple file without modifying coredns codebase:
```
package main
import (
_ "github.com/coredns/example"
"github.com/coredns/coredns/coremain"
"github.com/coredns/coredns/core/dnsserver"
)
var directives = []string{
"example",
"log",
"errors",
...
...
...
"whoami",
"startup",
"shutdown",
}
func init() {
dnsserver.Directives = directives
}
func main() {
coremain.Run()
}
```
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
115 lines
2.3 KiB
Go
115 lines
2.3 KiB
Go
//+build ignore
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package main
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import (
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"bufio"
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"go/format"
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"io/ioutil"
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"log"
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"os"
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"strings"
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)
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func main() {
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mi := make(map[string]string, 0)
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md := []string{}
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file, err := os.Open(pluginFile)
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if err != nil {
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log.Fatalf("Failed to open %s: %q", pluginFile, err)
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}
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defer file.Close()
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scanner := bufio.NewScanner(file)
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for scanner.Scan() {
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line := scanner.Text()
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if strings.HasPrefix(line, "#") {
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continue
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}
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items := strings.Split(line, ":")
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if len(items) != 2 {
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// ignore empty lines
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continue
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}
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name, repo := items[0], items[1]
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if _, ok := mi[name]; ok {
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log.Fatalf("Duplicate entry %q", name)
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}
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md = append(md, name)
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mi[name] = pluginPath + repo // Default, unless overridden by 3rd arg
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if _, err := os.Stat(pluginFSPath + repo); err != nil { // External package has been given
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mi[name] = repo
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}
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}
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genImports("core/zplugin.go", "core", mi)
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genDirectives("core/dnsserver/zdirectives.go", "dnsserver", md)
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}
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func genImports(file, pack string, mi map[string]string) {
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outs := header + "package " + pack + "\n\n" + "import ("
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if len(mi) > 0 {
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outs += "\n"
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}
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outs += "// Include all plugins.\n"
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for _, v := range mi {
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outs += `_ "` + v + `"` + "\n"
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}
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outs += ")\n"
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if err := formatAndWrite(file, outs); err != nil {
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log.Fatalf("Failed to format and write: %q", err)
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}
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}
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func genDirectives(file, pack string, md []string) {
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outs := header + "package " + pack + "\n\n"
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outs += `
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// Directives are registered in the order they should be
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// executed.
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//
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// Ordering is VERY important. Every plugin will
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// feel the effects of all other plugin below
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// (after) them during a request, but they must not
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// care what plugin above them are doing.
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var Directives = []string{
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`
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for i := range md {
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outs += `"` + md[i] + `",` + "\n"
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}
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outs += "}\n"
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if err := formatAndWrite(file, outs); err != nil {
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log.Fatalf("Failed to format and write: %q", err)
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}
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}
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func formatAndWrite(file string, data string) error {
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res, err := format.Source([]byte(data))
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if err != nil {
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return err
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}
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if err = ioutil.WriteFile(file, res, 0644); err != nil {
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return err
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}
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return nil
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}
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const (
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pluginPath = "github.com/coredns/coredns/plugin/"
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pluginFile = "plugin.cfg"
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pluginFSPath = "plugin/" // Where the plugins are located on the file system
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header = "// generated by directives_generate.go; DO NOT EDIT\n\n"
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)
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