update-imported-docs in golang (kubernetes#6642)

update-imported-docs/README

@@ -0,0 +1,5 @@
+update-imported-docs/update-imported-docs.go will update the target files generated from other repos.
+You should modify update-imported-docs/config.yaml to reflect the desired src and dst path.
+```
+go run update-imported-docs/update-imported-docs.go
+```

update-imported-docs/config.yaml

@@ -0,0 +1,14 @@
+repos:
+- name: kubernetes
+  remote: https://github.com/kubernetes/kubernetes.git
+  branch: release-1.9
+  files:
+  - src: docs/admin/cloud-controller-manager.md
+    dst: docs/reference/generated/cloud-controller-manager.md
+#- name: federation
+#  remote: https://github.com/kubernetes/federation.git
+#  # Change this to a release branch when federation has release branches.
+#  branch: master
+#  files:
+#  - src: a/foo.md
+#    dst: b/foo.md

update-imported-docs/update-imported-docs.go

@@ -0,0 +1,124 @@
+package main
+
+import (
+  "fmt"
+  "io"
+  "io/ioutil"
+  "os"
+  "os/exec"
+  "path"
+  "path/filepath"
+  "regexp"
+
+  "github.com/ghodss/yaml"
+)
+
+func main() {
+  websiteRepo, err := os.Getwd()
+  checkError(err)
+
+  content, err := ioutil.ReadFile("update-imported-docs/config.yaml")
+  if err != nil {
+    fmt.Fprintf(os.Stderr, "error when reading file: %v\n", err)
+    os.Exit(1)
+  }
+
+  var config map[string]interface{}
+  err = yaml.Unmarshal(content, &config)
+  if err != nil {
+    fmt.Fprintf(os.Stderr, "error when unmarshal the config file: %v\n", err)
+    os.Exit(1)
+  }
+
+  tmpDir := "/tmp/update_docs"
+  os.RemoveAll(tmpDir)
+  os.Mkdir(tmpDir, 0750)
+
+  // Match the content between 2 `---`
+  // It mostly have something like:
+  // ---
+  // title: ***
+  // notile: ***
+  // ---
+  titleRegex := regexp.MustCompile("^---\n(.*\n)*---\n")
+
+  repos := config["repos"].([]interface{})
+  for _, repo := range repos {
+    err = os.Chdir(tmpDir)
+    checkError(err)
+
+    r := repo.(map[string]interface{})
+    repoName := r["name"].(string)
+    cmd := "git"
+    args := []string{"clone", "--depth=1", "-b", r["branch"].(string), r["remote"].(string), repoName}
+    fmt.Fprintf(os.Stdout, "Cloning repo %q\n", repoName)
+    if err := exec.Command(cmd, args...).Run(); err != nil {
+      fmt.Fprintf(os.Stderr, "error when cloning repo %q: %v\n", repoName, err)
+      os.Exit(1)
+    }
+
+    err = os.Chdir(repoName)
+    checkError(err)
+
+    fmt.Fprintf(os.Stdout, "Generating docs for repo %q\n", repoName)
+    if err := exec.Command("hack/generate-docs.sh").Run(); err != nil {
+      fmt.Fprintf(os.Stderr, "error when generating docs for repo %q: %v\n", repoName, err)
+      os.Exit(1)
+    }
+
+    err = os.Chdir(websiteRepo)
+    checkError(err)
+    files := r["files"].([]interface{})
+    for _, file := range files {
+      f := file.(map[string]interface{})
+      src := f["src"].(string)
+      dst := f["dst"].(string)
+      absSrc, err := filepath.Abs(path.Join(tmpDir, repoName, src))
+      checkError(err)
+      absDst, err := filepath.Abs(dst)
+      checkError(err)
+      // Ignore the error if the old file is not found/
+      content, _ := ioutil.ReadFile(absDst)
+      titleBlock := titleRegex.Find(content)
+      content, err = ioutil.ReadFile(absSrc)
+      checkError(err)
+      dstFile, err := os.OpenFile(absDst, os.O_RDWR|os.O_CREATE, 0755)
+      checkError(err)
+      defer dstFile.Close()
+      _, err = dstFile.Write(titleBlock)
+      checkError(err)
+      _, err = dstFile.Write(content)
+      checkError(err)
+      dstFile.Sync()
+    }
+  }
+  fmt.Fprintf(os.Stdout, "Docs imported! Run 'git add .' 'git commit -m <comment>' and 'git push' to upload them\n")
+}
+
+func copyFile(src, dst string) error {
+  sf, err := os.Open(src)
+  if err != nil {
+    return err
+  }
+  defer sf.Close()
+
+  df, err := os.Create(dst)
+  if err != nil {
+    return err
+  }
+  defer df.Close()
+
+  _, err = io.Copy(df, sf)
+  if err != nil {
+    return err
+  }
+
+  return df.Sync()
+}
+
+func checkError(err error) {
+  if err != nil {
+    fmt.Fprintln(os.Stderr, err)
+    os.Exit(1)
+  }
+}