Merge pull request github#19636 from github/feature-versioning

Feature-based versioning

Dockerfile

@@ -52,6 +52,9 @@ COPY tsconfig.json ./tsconfig.json
 
 RUN npx tsc
 
+# We need to copy data in order to do the build
+COPY --chown=node:node data ./data
+
 RUN npm run build
 
 # --------------------------------------------------------------------------------
@@ -85,7 +88,6 @@ ENV AIRGAP true
 # Copy only what's needed to run the server
 COPY --chown=node:node assets ./assets
 COPY --chown=node:node content ./content
-COPY --chown=node:node data ./data
 COPY --chown=node:node includes ./includes
 COPY --chown=node:node layouts ./layouts
 COPY --chown=node:node lib ./lib

data/features/README.md

@@ -0,0 +1,52 @@
+## Feature-based versioning
+
+Feature-based versioning allows us to define and control the versions of an arbitrarily named "feature" in one place.
+
+**Note**: Do not delete `data/features/placeholder.yml` because it is used by tests.
+
+## How it works
+
+Add a new YAML file with the feature name you want to use in this directory. For a feature named `meow`, that would be `data/features/meow.yml`.
+
+Add a `versions` block to the YML file with the short names of the versions the feature is available in. For example:
+
+```yaml
+versions:
+  fpt: '*'
+  ghes: '>3.1'
+  ghae: '*'
+```
+
+The format and allowed values are the same as the [frontmatter versions property](/content#versions).
+
+### Liquid conditionals
+
+Now you can use `{% if meow %} ... {% endif %}` in content files! Note this is the `if` tag, not the new `ifversion` tag.
+
+### Frontmatter
+
+You can also use the feature in frontmatter in content files:
+
+```yaml
+versions:
+  fpt: '*'
+  ghes: '>3.1'
+  feature: 'meow'
+```
+
+If you want a content file to apply to more than one feature, you can do this:
+
+```yaml
+versions:
+  fpt: '*'
+  ghes: '>3.1'
+  feature: ['meow', 'blorp']
+```
+
+## Schema enforcement
+
+The schema for validating the feature versioning lives in [`tests/helpers/schemas/feature-versions.js`](tests/helpers/schemas/feature-versions.js) and is exercised by [`tests/content/lint-files.js`](tests/content/lint-files.js).
+
+## Script to remove feature tags
+
+TBD!

data/features/placeholder.yml

@@ -0,0 +1,4 @@
+# Do not delete! Used by tests.
+versions:
+  ghes: '>3.0'
+  ghae: '*'

lib/frontmatter.js

@@ -1,3 +1,5 @@
+const fs = require('fs')
+const path = require('path')
 const parse = require('./read-frontmatter')
 const semver = require('semver')
 const layouts = require('./layouts')
@@ -9,8 +11,10 @@ const semverRange = {
   conform: semverValidRange,
   message: 'Must be a valid SemVer range'
 }
-const versionIds = Object.keys(require('./all-versions'))
+const versionObjs = Object.values(require('./all-versions'))
 const guideTypes = ['overview', 'quick_start', 'tutorial', 'how_to', 'reference']
+const featureVersions = fs.readdirSync(path.posix.join(process.cwd(), 'data/features'))
+  .map(file => path.basename(file, '.yml'))
 
 const schema = {
   properties: {
@@ -197,15 +201,31 @@ const schema = {
   }
 }
 
+const featureVersionsProp = {
+  feature: {
+    type: ['string', 'array'],
+    enum: featureVersions,
+    items: {
+      type: 'string'
+    },
+    message: 'must be the name (or names) of a feature that matches "filename" in data/features/_filename_.yml'
+ }
+}
+
 schema.properties.versions = {
   type: ['object', 'string'], // allow a '*' string to indicate all versions
   required: true,
-  properties: versionIds.reduce((acc, versionId) => {
-    acc[versionId] = semverRange
+  properties: versionObjs.reduce((acc, versionObj) => {
+    acc[versionObj.plan] = semverRange
+    acc[versionObj.shortName] = semverRange
     return acc
-  }, {})
+  }, featureVersionsProp)
 }
 
+// Support 'github-ae': next
+schema.properties.versions.properties['github-ae'] = 'next'
+schema.properties.versions.properties.ghae = 'next'
+
 function frontmatter (markdown, opts = {}) {
   const defaults = {
     schema,

lib/get-applicable-versions.js

@@ -1,6 +1,17 @@
+const path = require('path')
+const { reduce, sortBy } = require('lodash')
 const allVersions = require('./all-versions')
 const versionSatisfiesRange = require('./version-satisfies-range')
 const checkIfNextVersionOnly = require('./check-if-next-version-only')
+const dataDirectory = require('./data-directory')
+const encodeBracketedParentheses = require('./encode-bracketed-parentheses')
+const featuresDir = path.posix.join(__dirname, '../data/features')
+
+const featureData = dataDirectory(featuresDir, {
+  preprocess: dataString =>
+    encodeBracketedParentheses(dataString.trimEnd()),
+  ignorePatterns: [/README\.md$/]
+})
 
 // return an array of versions that an article's product versions encompasses
 function getApplicableVersions (frontmatterVersions, filepath) {
@@ -13,17 +24,63 @@ function getApplicableVersions (frontmatterVersions, filepath) {
     return Object.keys(allVersions)
   }
 
-  // get an array like: [ 'free-pro-team@latest', '[email protected]', 'enterprise-cloud@latest' ]
-  const applicableVersions = []
+  // Check for frontmatter that includes a feature name, like:
+  //    fpt: '*'
+  //    feature: 'foo'
+  // or multiple feature names, like:
+  //    fpt: '*'
+  //    feature: ['foo', 'bar']
+  // and add the versions affiliated with the feature (e.g., foo) to the frontmatter versions object:
+  //    fpt: '*'
+  //    ghes: '>=2.23'
+  //    ghae: '*'
+  // where the feature is bringing the ghes and ghae versions into the mix.
+  const featureVersions = reduce(frontmatterVersions, (result, value, key) => {
+    if (key === 'feature') {
+      if (typeof value === 'string') {
+        Object.assign(result, { ...featureData[value].versions })
+      } else if (Array.isArray(value)) {
+        value.forEach(str => {
+          Object.assign(result, { ...featureData[str].versions })
+        })
+      }
+      delete result[key]
+    }
+    return result
+  }, {})
+
+  // We will be evaluating feature versions separately, so we can remove this.
+  delete frontmatterVersions.feature
+
+  // Get available versions for frontmatter and for feature versions.
+  const foundFeatureVersions = evaluateVersions(featureVersions)
+  const foundFrontmatterVersions = evaluateVersions(frontmatterVersions)
+
+  // Combine them!
+  const applicableVersions = [...new Set(foundFrontmatterVersions.versions.concat(foundFeatureVersions.versions))]
+
+  if (!applicableVersions.length && !foundFrontmatterVersions.isNextVersionOnly && !foundFeatureVersions.isNextVersionOnly) {
+    throw new Error(`No applicable versions found for ${filepath}. Please double-check the page's \`versions\` frontmatter.`)
+  }
 
+  // Sort them by the order in lib/all-versions.
+  const sortedVersions = sortBy(applicableVersions, (v) => { return Object.keys(allVersions).indexOf(v) })
+
+  return sortedVersions
+}
+
+function evaluateVersions (versionsObj) {
   let isNextVersionOnly = false
 
-  // where frontmatter is something like:
+  // get an array like: [ 'free-pro-team@latest', '[email protected]', 'enterprise-cloud@latest' ]
+  const versions = []
+
+  // where versions obj is something like:
   //   fpt: '*'
   //   ghes: '>=2.19'
   //   ghae: '*'
   // ^ where each key corresponds to a plan's short name (defined in lib/all-versions.js)
-  Object.entries(frontmatterVersions)
+  Object.entries(versionsObj)
     .forEach(([plan, planValue]) => {
       // Special handling for frontmatter that evalues to the next GHES release number or a hardcoded `next`.
       isNextVersionOnly = checkIfNextVersionOnly(planValue)
@@ -37,16 +94,12 @@ function getApplicableVersions (frontmatterVersions, filepath) {
           const versionToCompare = relevantVersion.hasNumberedReleases ? relevantVersion.currentRelease : '1.0'
 
           if (versionSatisfiesRange(versionToCompare, planValue)) {
-            applicableVersions.push(relevantVersion.version)
+            versions.push(relevantVersion.version)
           }
         })
     })
 
-  if (!applicableVersions.length && !isNextVersionOnly) {
-    throw new Error(`No applicable versions found for ${filepath}. Please double-check the page's \`versions\` frontmatter.`)
-  }
-
-  return applicableVersions
+  return { versions, isNextVersionOnly }
 }
 
 module.exports = getApplicableVersions

middleware/contextualizers/features.js

@@ -0,0 +1,18 @@
+const getApplicableVersions = require('../../lib/get-applicable-versions')
+
+module.exports = async function features (req, res, next) {
+  if (!req.context.page) return next()
+
+  // Determine whether the currentVersion belongs to the list of versions the feature is available in.
+  Object.keys(req.context.site.data.features).forEach(featureName => {
+    const { versions } = req.context.site.data.features[featureName]
+    const applicableVersions = getApplicableVersions(versions, req.path)
+
+    // Adding the resulting boolean to the context object gives us the ability to use
+    // `{% if featureName ... %}` conditionals in content files.
+    const isFeatureAvailableInCurrentVersion = applicableVersions.includes(req.context.currentVersion)
+    req.context[featureName] = isFeatureAvailableInCurrentVersion
+  })
+
+  return next()
+}

middleware/index.js

@@ -51,6 +51,7 @@ const currentProductTree = require('./contextualizers/current-product-tree')
 const genericToc = require('./contextualizers/generic-toc')
 const breadcrumbs = require('./contextualizers/breadcrumbs')
 const earlyAccessBreadcrumbs = require('./contextualizers/early-access-breadcrumbs')
+const features = require('./contextualizers/features')
 const productExamples = require('./contextualizers/product-examples')
 const devToc = require('./dev-toc')
 const featuredLinks = require('./featured-links')
@@ -180,6 +181,7 @@ module.exports = function (app) {
   app.use(asyncMiddleware(instrument(genericToc, './contextualizers/generic-toc')))
   app.use(asyncMiddleware(instrument(breadcrumbs, './contextualizers/breadcrumbs')))
   app.use(asyncMiddleware(instrument(earlyAccessBreadcrumbs, './contextualizers/early-access-breadcrumbs')))
+  app.use(asyncMiddleware(instrument(features, './contextualizers/features')))
   app.use(asyncMiddleware(instrument(productExamples, './contextualizers/product-examples')))
 
   app.use(asyncMiddleware(instrument(devToc, './dev-toc')))

tests/fixtures/feature-versions-frontmatter.md

@@ -0,0 +1,7 @@
+---
+title: Some article only versioned for FPT
+versions: 
+  fpt: '*'
+  ghes: '>2.21'
+  feature: 'placeholder'
+---

tests/helpers/schemas/feature-versions-schema.js

@@ -0,0 +1,18 @@
+const { schema } = require('../../../lib/frontmatter')
+
+// Copy the properties from the frontmatter schema.
+const featureVersions = {
+  properties: {
+    versions: Object.assign({}, schema.properties.versions)
+  }
+}
+
+// Remove the feature versions properties.
+// We don't want to allow features within features! We just want pure versioning.
+delete featureVersions.properties.versions.properties.feature
+
+// Call it invalid if any properties other than version properties are found.
+featureVersions.additionalProperties = false
+featureVersions.properties.versions.additionalProperties = false
+
+module.exports = featureVersions