Fix snapshot deletion after VM export.

src/api/vm.coffee

@@ -239,28 +239,8 @@ exports.create = create
 
 #---------------------------------------------------------------------
 
-delete_ = $coroutine ({vm, delete_disks: deleteDisks}) ->
-  if $isVMRunning vm
-    @throw 'INVALID_PARAMS', 'The VM can only be deleted when halted'
-
-  xapi = @getXAPI vm
-
-  if deleteDisks
-    $forEach vm.$VBDs, (ref) =>
-      try
-        VBD = @getObject ref, 'VBD'
-      catch e
-        return
-
-      return if VBD.read_only or not VBD.VDI?
-
-      $wait xapi.call 'VDI.destroy', VBD.VDI
-
-      return
-
-  $wait xapi.call 'VM.destroy', vm.ref
-
-  return true
+delete_ = ({vm, delete_disks: deleteDisks}) ->
+  return @getXAPI(vm).deleteVm(vm.id, deleteDisks)
 
 delete_.params = {
   id: { type: 'string' }
@@ -819,17 +799,19 @@ export_ = $coroutine ({vm, compress}) ->
   )
   pFinally(
     xapi._watchTask(task)
-      .then (result) ->
+      .then((result) ->
         $debug 'export succeeded'
         return
-      .catch (error) ->
+      )
+      .catch((error) ->
         $debug 'export failed: %j', error
         return
+      )
     ,
-    $coroutine =>
+    ->
       if snapshotRef?
         $debug 'deleting temp snapshot...'
-        $wait exports.delete.call this, id: snapshotRef, delete_disks: true
+        xapi.deleteVm(snapshotRef, true)
 
       return
   )

src/utils.js

@@ -68,6 +68,13 @@ export const parseXml = (function () {
 
 // -------------------------------------------------------------------
 
+// This function does nothing and returns undefined.
+//
+// It is often used to swallow promise's errors.
+export function noop () {}
+
+// -------------------------------------------------------------------
+
 // Ponyfill for Promise.finally(cb)
 export const pFinally = (promise, cb) => {
   return promise.then(

src/xapi.js

@@ -9,7 +9,7 @@ import {promisify} from 'bluebird'
 import {Xapi as XapiBase} from 'xen-api'
 
 import {debounce} from './decorators'
-import {ensureArray, parseXml, pFinally} from './utils'
+import {ensureArray, noop, parseXml, pFinally} from './utils'
 import {JsonRpcError} from './api-errors'
 
 const debug = createDebug('xo:xapi')
@@ -61,6 +61,14 @@ const getNamespaceForType = (type) => typeToNamespace[type] || type
 
 // ===================================================================
 
+const VM_RUNNING_POWER_STATES = {
+  Running: true,
+  Paused: true
+}
+const isVmRunning = (vm) => VM_RUNNING_POWER_STATES[vm.power_state]
+
+// ===================================================================
+
 export default class Xapi extends XapiBase {
   constructor (...args) {
     super(...args)
@@ -454,6 +462,33 @@ export default class Xapi extends XapiBase {
 
   // =================================================================
 
+  async _deleteVdi (vdiId) {
+    const vdi = this.getObject(vdiId)
+
+    await this.call('VDI.destroy', vdi.$ref)
+  }
+
+  async deleteVm (vmId, deleteDisks = false) {
+    const vm = this.getObject(vmId)
+
+    if (isVmRunning(vm)) {
+      throw new Error('running VMs cannot be deleted')
+    }
+
+    if (deleteDisks) {
+      // TODO: simplify when we start to use xen-api >= 0.5
+      await Promise.all(map(vm.VBDs, ref => {
+        try {
+          return this._deleteVdi(this.getObject(ref).VDI).catch(noop)
+        } catch (_) {}
+      }))
+    }
+
+    await this.call('VM.destroy', vm.$ref)
+  }
+
+  // =================================================================
+
   async _doDockerAction (vmId, action, containerId) {
     const vm = this.getObject(vmId)
     const host = this.getObject(vm.resident_on)