feat: autodetect base when not specified by the user (#47)

package.json

@@ -39,7 +39,8 @@
     "eslint-plugin-node": "^10.0.0",
     "eslint-plugin-promise": "^4.0.1",
     "eslint-plugin-standard": "^4.0.0",
-    "nyc": "^14.0.0"
+    "nyc": "^14.0.0",
+    "sinon": "^7.5.0"
   },
   "dependencies": {
     "cross-spawn-promise": "^0.10.1",

src/yaml.js

@@ -22,6 +22,8 @@ const merge = require('lodash.merge')
 const path = require('path')
 const pull = require('lodash.pull')
 const semver = require('semver')
+const spawn = require('cross-spawn-promise')
+const which = require('which')
 const yaml = require('js-yaml')
 
 const { createDesktopLaunchCommand } = require('./launcher')
@@ -73,6 +75,41 @@ class SnapcraftYAML {
     return this.data.parts[this.appName]
   }
 
+  async detectBase (lsbRelease) {
+    if (!lsbRelease) {
+      lsbRelease = 'lsb_release'
+    }
+    const lsbReleasePath = await this.findLsbRelease(lsbRelease)
+    if (!lsbReleasePath) {
+      debug('Using base: core18 as recommended by the Snapcraft docs')
+      return 'core18'
+    }
+
+    const [distro, distroVersion] = await this.detectDistro(lsbReleasePath)
+    if (distro === 'Ubuntu' && distroVersion === '16.04') {
+      return 'core'
+    }
+
+    return 'core18'
+  }
+
+  async findLsbRelease (lsbRelease) {
+    try {
+      return await which(lsbRelease)
+    } catch (err) {
+      debug(`Error when looking for lsb_release:\n${err}`)
+    }
+  }
+
+  async detectDistro (lsbRelease) {
+    const output = await spawn(lsbRelease, ['--short', '--id', '--release'])
+    if (output) {
+      return output.toString().trim().split('\n')
+    }
+
+    return [null, null]
+  }
+
   renameSubtree (parentObject, fromKey, toKey) {
     parentObject[toKey] = parentObject[fromKey]
     delete parentObject[fromKey]
@@ -174,6 +211,12 @@ class SnapcraftYAML {
     this.features = merge({}, userSupplied.features || {})
     delete userSupplied.features
 
+    if (!userSupplied.base) {
+      // eslint-disable-next-line require-atomic-updates
+      userSupplied.base = await this.detectBase(userSupplied.lsbRelease)
+    }
+    delete userSupplied.lsbRelease
+
     const appConfig = { apps: { electronApp: userSupplied.appConfig || {} } }
     delete userSupplied.appConfig
     const appPlugsSlots = { apps: { electronApp: {} } }
@@ -213,3 +256,5 @@ module.exports = async function createYamlFromTemplate (snapDir, packageDir, use
   await yamlData.transform(packageDir, userSupplied)
   await yamlData.write(path.join(snapDir, 'snap', 'snapcraft.yaml'))
 }
+
+module.exports.SnapcraftYAML = SnapcraftYAML

test/yaml.js

@@ -18,10 +18,13 @@ limitations under the License.
 const createYamlFromTemplate = require('../src/yaml')
 const fs = require('fs-extra')
 const path = require('path')
+const sinon = require('sinon')
 const test = require('ava')
 const util = require('./_util')
 const yaml = require('js-yaml')
 
+const SnapcraftYAML = createYamlFromTemplate.SnapcraftYAML
+
 async function createYaml (t, userDefined, electronVersion) {
   const yamlPath = path.join(t.context.tempDir.name, 'snap', 'snapcraft.yaml')
   if (typeof electronVersion === 'undefined') {
@@ -141,3 +144,41 @@ test('Electron 4 apps require uuid', async t => {
   const snapcraftYaml = await createYaml(t, { name: 'electronAppName' }, '4.0.0')
   assertStagedPackage(t, snapcraftYaml, 'libuuid1')
 })
+
+test('base autodetect defaults to core18 when lsb_release is not found', async t => {
+  const snapcraftYaml = await createYaml(t, { name: 'electronAppName', lsbRelease: '/does/not/exist' })
+  t.is(snapcraftYaml.base, 'core18')
+})
+
+test('base autodetect does not run when it is set by the user', async t => {
+  const snapcraftYaml = await createYaml(t, { name: 'electronAppName', base: 'bare' })
+  t.is(snapcraftYaml.base, 'bare')
+})
+
+test('base autodetect returns core when Ubuntu 16.04 is detected', async t => {
+  const yaml = new SnapcraftYAML()
+  const lsbRelease = sinon.stub(yaml, 'findLsbRelease')
+  lsbRelease.resolves('lsb_release')
+  const distro = sinon.stub(yaml, 'detectDistro')
+  distro.resolves(['Ubuntu', '16.04'])
+  try {
+    t.is('core', await yaml.detectBase())
+  } finally {
+    lsbRelease.restore()
+    distro.restore()
+  }
+})
+
+test('base autodetect returns core18 for non-Ubuntu distros', async t => {
+  const yaml = new SnapcraftYAML()
+  const lsbRelease = sinon.stub(yaml, 'findLsbRelease')
+  lsbRelease.resolves('lsb_release')
+  const distro = sinon.stub(yaml, 'detectDistro')
+  distro.resolves(['Debian', '10'])
+  try {
+    t.is('core18', await yaml.detectBase())
+  } finally {
+    lsbRelease.restore()
+    distro.restore()
+  }
+})