Implement mungedocs example syncer

Author: janetkuo

cmd/mungedocs/example_syncer.go

@@ -0,0 +1,115 @@
+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"path"
+	"regexp"
+	"strings"
+)
+
+const exampleMungeTag = "EXAMPLE"
+
+// syncExamples updates all examples in markdown file.
+//
+// Finds the magic macro block tags, find the link to the example
+// specified in the tags, and replaces anything between those with
+// the content of the example, thereby syncing it.
+//
+// For example,
+// <!-- BEGIN MUNGE: EXAMPLE ../../examples/guestbook/frontend-controller.yaml -->
+//
+// ```yaml
+// foo:
+//    bar:
+// ```
+//
+// [Download example](../../examples/guestbook/frontend-controller.yaml)
+// <!-- END MUNGE: EXAMPLE -->
+func syncExamples(filePath string, markdown []byte) ([]byte, error) {
+	// find the example syncer begin tag
+	header := beginMungeTag(fmt.Sprintf("%s %s", exampleMungeTag, `(([^ ])*.(yaml|json))`))
+	exampleLinkRE := regexp.MustCompile(header)
+	lines := splitLines(markdown)
+	updatedMarkdown, err := updateExampleMacroBlock(filePath, lines, exampleLinkRE, endMungeTag(exampleMungeTag))
+	if err != nil {
+		return updatedMarkdown, err
+	}
+	return updatedMarkdown, nil
+}
+
+// exampleContent retrieves the content of the file at linkPath
+func exampleContent(filePath, linkPath, fileType string) (content string, err error) {
+	realRoot := path.Join(*rootDir, *repoRoot) + "/"
+	path := path.Join(realRoot, path.Dir(filePath), linkPath)
+	dat, err := ioutil.ReadFile(path)
+	if err != nil {
+		return content, err
+	}
+	content = fmt.Sprintf("\n```%s\n%s\n```\n\n[Download example](%s)", fileType, string(dat), linkPath)
+	return
+}
+
+// updateExampleMacroBlock sync the yaml/json example between begin tag and end tag
+func updateExampleMacroBlock(filePath string, lines []string, beginMarkExp *regexp.Regexp, endMark string) ([]byte, error) {
+	var buffer bytes.Buffer
+	betweenBeginAndEnd := false
+	for _, line := range lines {
+		trimmedLine := strings.Trim(line, " \n")
+		if beginMarkExp.Match([]byte(trimmedLine)) {
+			if betweenBeginAndEnd {
+				return nil, fmt.Errorf("found second begin mark while updating macro blocks")
+			}
+			betweenBeginAndEnd = true
+			buffer.WriteString(line)
+			buffer.WriteString("\n")
+			match := beginMarkExp.FindStringSubmatch(line)
+			if len(match) < 4 {
+				return nil, fmt.Errorf("failed to parse the link in example header")
+			}
+			// match[0] is the entire expression; [1] is the link text and [3] is the file type (yaml or json).
+			linkText := match[1]
+			fileType := match[3]
+			example, err := exampleContent(filePath, linkText, fileType)
+			if err != nil {
+				return nil, err
+			}
+			buffer.WriteString(example)
+		} else if trimmedLine == endMark {
+			if !betweenBeginAndEnd {
+				return nil, fmt.Errorf("found end mark without being mark while updating macro blocks")
+			}
+			// Extra newline avoids github markdown bug where comment ends up on same line as last bullet.
+			buffer.WriteString("\n")
+			buffer.WriteString(line)
+			buffer.WriteString("\n")
+			betweenBeginAndEnd = false
+		} else {
+			if !betweenBeginAndEnd {
+				buffer.WriteString(line)
+				buffer.WriteString("\n")
+			}
+		}
+	}
+	if betweenBeginAndEnd {
+		return nil, fmt.Errorf("never found closing end mark while updating macro blocks")
+	}
+	return buffer.Bytes(), nil
+}

cmd/mungedocs/example_syncer_test.go

@@ -0,0 +1,58 @@
+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_syncExamples(t *testing.T) {
+	var podExample = `apiVersion: v1
+kind: Pod
+metadata:
+  name: nginx
+spec:
+  containers:
+  - name: nginx
+    image: nginx
+    ports:
+    - containerPort: 80
+`
+	var cases = []struct {
+		in  string
+		out string
+	}{
+		{"", ""},
+		{
+			"<!-- BEGIN MUNGE: EXAMPLE testdata/pod.yaml -->\n<!-- END MUNGE: EXAMPLE -->\n",
+			"<!-- BEGIN MUNGE: EXAMPLE testdata/pod.yaml -->\n\n```yaml\n" + podExample + "```\n\n[Download example](testdata/pod.yaml)\n<!-- END MUNGE: EXAMPLE -->\n",
+		},
+		{
+			"<!-- BEGIN MUNGE: EXAMPLE ../mungedocs/testdata/pod.yaml -->\n<!-- END MUNGE: EXAMPLE -->\n",
+			"<!-- BEGIN MUNGE: EXAMPLE ../mungedocs/testdata/pod.yaml -->\n\n```yaml\n" + podExample + "```\n\n[Download example](../mungedocs/testdata/pod.yaml)\n<!-- END MUNGE: EXAMPLE -->\n",
+		},
+	}
+	for _, c := range cases {
+		actual, err := syncExamples("mungedocs/filename.md", []byte(c.in))
+		assert.NoError(t, err)
+		if c.out != string(actual) {
+			t.Errorf("Expected example \n'%v' but got \n'%v'", c.out, string(actual))
+		}
+	}
+}

cmd/mungedocs/mungedocs.go

@@ -52,6 +52,7 @@ Examples:
 		{"unversioned-warning", updateUnversionedWarning},
 		{"analytics", checkAnalytics},
 		{"kubectl-dash-f", checkKubectlFileTargets},
+		{"sync-examples", syncExamples},
 	}
 	availableMungeList = func() string {
 		names := []string{}

cmd/mungedocs/testdata/pod.yaml

@@ -0,0 +1,10 @@
+apiVersion: v1
+kind: Pod
+metadata:
+  name: nginx
+spec:
+  containers:
+  - name: nginx
+    image: nginx
+    ports:
+    - containerPort: 80