Extension: Implement dynamic loading attributes

Author: mmattel

ext-antora/load-global-site-attributes.js

@@ -0,0 +1,111 @@
+// v1.0.0
+"use strict"
+
+const fs    = require('fs')
+const http  = require('http')
+const https = require('https')
+const yaml  = require('js-yaml')
+
+// this extension loads (global) attributes into the playbook (site.yml)
+// !! attributes in the playbook take precedence over loaded attributes !!
+// allows test building a repo like in multi repo envs with custom local attribute values
+// you can temporarily disable loading by setting 'enabled: false'
+// error handling:
+//   if no 'attributefile' is configured: warn, but continue processing
+//   if loading or processing the file caused an error (like file not found, needs fixing): stop
+
+module.exports.register = function ({ config }) {
+    const logger = this.getLogger('load-global-site-attributes-extension')
+    let attrib_file   = ''
+    let attrib_yaml   = {}
+    let orig_playbook = {}
+    let result        = {}
+
+    this.on("playbookBuilt", async ({ playbook }) => {
+      // get the original playbook asciidoc attributes, note it can be empty
+      orig_playbook = JSON.parse(JSON.stringify(playbook.asciidoc.attributes)) || {}
+
+      // only if attributefile is configured in site.yml pointing to a resource (file or url)
+      if (config.attributefile) {
+        try {
+          // define the get function to use and load the file
+          if (config.attributefile.startsWith('http')) {
+            attrib_file = await get_file_from_url(config.attributefile)
+          } else {
+            attrib_file = await get_file_from_local(config.attributefile)
+          }
+
+          // convert and update
+          attrib_yaml = await convert_yaml(attrib_file)
+          result = Object.assign(attrib_yaml, playbook.asciidoc.attributes)
+          playbook.asciidoc.attributes = result
+          this.updateVariables( playbook )
+
+        // loading or processing the file caused an error
+        } catch (error) {
+            logger.error(error)
+            this.stop()
+        }
+      } else {
+        logger.warn('attributefile is not configured in the playbook (site.yml).')
+      }
+//      console.log(this.getVariables())
+    })
+}
+
+function get_file_from_url(url) {
+    // promise a file from url
+    // when executed it returns the contents if found
+    return new Promise((resolve, reject) => {
+      const client = url.startsWith('https') ? https : http
+      const req = client.request(url, (res) => {
+        if (res.statusCode < 200 || res.statusCode >= 300) {
+              reject(`Request Failed.\n` +
+                     `Status Code: ${res.statusCode}\n` +
+                     `${url}`)
+          }
+          var body = []
+          res.on('data', function(chunk) {
+              body.push(chunk)
+          })
+          res.on('end', function() {
+              try {
+                  body = Buffer.concat(body).toString()
+              } catch(error) {
+                  reject(error)
+              }
+              resolve(body)
+          })
+      })
+      req.on('error', (error) => {
+        reject(error.message)
+      })
+      // send the request
+      req.end()
+    })
+}
+
+function get_file_from_local(file) {
+    // promise a file from local filesystem
+    // when executed it returns the contents if found
+    return new Promise((resolve, reject) => {
+      fs.readFile(file, 'utf8', (error, data) => {
+        if (error) reject(error)
+        resolve(data)
+      })
+    })
+}
+
+function convert_yaml(data) {
+    // promise to parse yaml data
+    // when executed it returns the parsed contents
+    return new Promise((resolve, reject) => {
+      try {
+        var d = yaml.load(data)
+      // the parser found an error, no object will be returned
+      } catch (error) {
+        reject(`yaml parser: ` + error)
+      }
+      resolve(d)
+    })
+}

ext-asciidoc/ext-antora/generate-index.js

@@ -41,6 +41,7 @@
     "asciidoctor-kroki": "^0.18.1",
     "cheerio": "^1.0.0",
     "html-entities": "2.5.2",
+    "js-yaml": "^4.1.0",
     "lodash": "^4.17.21"
   },
   "devDependencies": {