Add new windows module: win_hosts (#46450)

* Add win_hosts module

added win_hosts module for easier manipulation of hosts entries in "%windir%\system32\drivers\etc\hosts" for windows systems

* Update win_hosts.py

* Add alias support to win_hosts module (#1)

* win_hosts supports aliases

added support for adding / removing aliases from a host entry, rather than adding a new entry

added ability for win_hosts to detect aliases:
`192.168.1.1 alias1 alias2 alias3`
```
win_hosts:
  host_name: alias2
  ip_address: 192.168.1.1
```
will result in `192.168.1.1 alias1 alias3`

also includes `replace` and `add` as options for `ip_action` (`replace` is default)

for example:
```
192.168.1.1 my_reused_alias
192.168.1.2 my_reused_alias
```
with
```
win_hosts:
  host_name: my_reused_alias
  ip_address: 192.168.1.3
  ip_action: add
```
the result will be
```
192.168.1.1 my_reused_alias
192.168.1.2 my_reused_alias
```
but with `ip_action=replace` the result would be
```
192.168.1.3 my_reused_alias
```

* fixed metadata version and version added

* fix line endings

* upload fixed line endings

try to upload the file with the fixed line endings

* aliases and canonical names are separate entities. added IPv4 and IPv6 validation

* only makes changes if "check_mode" is false

* improved behavior for duplicate aliases/entries.

* adding tests

* missing aliases file

* fix trailing whitespace and uses explicit paths

* Tweak tests to copy and restore original hosts file

lib/ansible/modules/windows/win_hosts.ps1

@@ -0,0 +1,298 @@
+#!powershell
+
+# Copyright: (c) 2018, Micah Hunsberger (@mhunsber)
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+#Requires -Module Ansible.ModuleUtils.Legacy
+
+Set-StrictMode -Version 2
+$ErrorActionPreference = "Stop"
+
+$params = Parse-Args -arguments $args -supports_check_mode $true
+$check_mode = Get-AnsibleParam -obj $params -name "_ansible_check_mode" -type "bool" -default $false
+$diff_mode = Get-AnsibleParam -obj $params -name "_ansible_diff" -type "bool" -default $false
+
+$state = Get-AnsibleParam -obj $params -name "state" -type "str" -default "present" -validateset "absent","present"
+$aliases = Get-AnsibleParam -obj $params -name "aliases" -type "list" -failifempty $false
+$canonical_name = Get-AnsibleParam -obj $params -name "canonical_name" -type "str" -failifempty ($state -eq 'present')
+$ip_address = Get-AnsibleParam -obj $params -name "ip_address" -type "str" -default "" -failifempty ($state -eq 'present')
+$action = Get-AnsibleParam -obj $params -name "action" -type "str" -default "set" -validateset "add","remove","set"
+
+$tmp = [ipaddress]::None
+if($ip_address -and -not [ipaddress]::TryParse($ip_address, [ref]$tmp)){
+    Fail-Json -obj @{} -message "win_hosts: Argument ip_address needs to be a valid ip address, but was $ip_address"
+}
+$ip_address_type = $tmp.AddressFamily
+
+$hosts_file = Get-Item -LiteralPath "$env:SystemRoot\System32\drivers\etc\hosts"
+
+$result = @{
+    changed = $false
+    diff = @{
+        prepared = ""
+    }
+}
+
+Function Get-CommentIndex($line) {
+    $c_index = $line.IndexOf('#')
+    if($c_index -lt 0) {
+        $c_index = $line.Length
+    }
+    return $c_index
+}
+
+Function Get-HostEntryParts($line) {
+    $success = $true
+    $c_index = Get-CommentIndex -line $line
+    $pure_line = $line.Substring(0,$c_index).Trim()
+    $bits = $pure_line -split "\s+"
+    if($bits.Length -lt 2){
+        return @{
+            success = $false
+            ip_address = ""
+            ip_type = ""
+            canonical_name = ""
+            aliases = @()
+        }
+    }
+    $ip_obj = [ipaddress]::None
+    if(-not [ipaddress]::TryParse($bits[0], [ref]$ip_obj) ){
+        $success = $false
+    }
+    $cname = $bits[1]
+    $als = New-Object string[] ($bits.Length - 2)
+    [array]::Copy($bits, 2, $als, 0, $als.Length)
+    return @{
+        success = $success
+        ip_address = $ip_obj.IPAddressToString
+        ip_type = $ip_obj.AddressFamily
+        canonical_name = $cname
+        aliases = $als
+    }
+}
+
+Function Find-HostName($line, $name) {
+    $c_idx = Get-CommentIndex -line $line
+    $re = New-Object regex ("\s+$($name.Replace('.',"\."))(\s|$)", [System.Text.RegularExpressions.RegexOptions]::IgnoreCase)
+    $match = $re.Match($line, 0, $c_idx)
+    return $match
+}
+
+Function Remove-HostEntry($list, $idx) {
+    $result.changed = $true
+    $removed = $false
+
+    if($diff_mode) {
+        $result.diff.prepared += "`n-[$($list[$idx])]`n"
+    }
+
+    if(-not $check_mode) {
+        $list.RemoveAt($idx)
+        $removed = $true
+    }
+
+    return $removed
+}
+
+Function Add-HostEntry($list, $cname, $aliases, $ip) {
+    $result.changed = $true
+    $line = "$ip $cname $($aliases -join ' ')"
+    if($diff_mode) {
+        $result.diff.prepared += "`n+[$line]`n"
+    }
+    if(-not $check_mode) {
+        $list.Add($line) | Out-Null
+    }
+}
+
+Function Remove-HostnamesFromEntry($list, $idx, $aliases) {
+    $line = $list[$idx]
+    $line_removed = $false
+
+    foreach($name in $aliases){
+        $match = Find-HostName -line $line -name $name
+        if($match.Success){
+            $line = $line.Remove($match.Index + 1, $match.Length -1)
+            # was this the last alias? (check for space characters after trimming)
+            if($line.Substring(0,(Get-CommentIndex -line $line)).Trim() -inotmatch "\s") {
+                if($diff_mode){
+                    $result.diff.prepared += "`n-[$($list[$idx])]`n"
+                }
+                if(-not $check_mode) {
+                    $list.RemoveAt($idx)
+                    $line_removed = $true
+                }
+                # we're done
+                return @{
+                    line_removed = $line_removed
+                }
+            }
+        }
+    }
+    if($line -ne $list[$idx]){
+        $result.changed = $true
+        if($diff_mode) {
+            $result.diff.prepared += "`n-[$($list[$idx])]`n+[$line]`n"
+        }
+        if(-not $check_mode) {
+            $list[$idx] = $line
+        }
+    }
+    return @{
+        line_removed = $line_removed
+    }
+}
+
+Function Add-AliasesToEntry($list, $idx, $aliases) {
+    $line = $list[$idx]
+    foreach($name in $aliases){
+        $match = Find-HostName -line $line -name $name
+        if(-not $match.Success) {
+            # just add the alias before the comment
+            $line = $line.Insert((Get-CommentIndex -line $line), " $name ")
+        }
+    }
+    if($line -ne $list[$idx]){
+        $result.changed = $true
+        if($diff_mode) {
+            $result.diff.prepared += "`n-[$($list[$idx])]`n+[$line]`n"
+        }
+        if(-not $check_mode) {
+            $list[$idx] = $line
+        }
+    }
+}
+
+$hosts_lines = New-Object System.Collections.ArrayList
+
+Get-Content -LiteralPath $hosts_file.FullName | ForEach-Object { $hosts_lines.Add($_) } | Out-Null
+
+if ($state -eq 'absent') {
+    # go through and remove canonical_name and ip
+    for($idx = 0; $idx -lt $hosts_lines.Count; $idx++) {
+        $entry = $hosts_lines[$idx]
+         # skip comment lines
+         if(-not $entry.Trim().StartsWith('#')) {
+            $entry_parts = Get-HostEntryParts -line $entry
+            if($entry_parts.success) {
+                if(-not $ip_address -or $entry_parts.ip_address -eq $ip_address) {
+                    if(-not $canonical_name -or $entry_parts.canonical_name -eq $canonical_name) {
+                        if(Remove-HostEntry -list $hosts_lines -idx $idx){
+                            # keep index correct if we removed the line
+                            $idx = $idx - 1
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+if($state -eq 'present') {
+    $entry_idx = -1
+    $aliases_to_keep = @()
+    # go through lines, find the entry and determine what to remove based on action
+    for($idx = 0; $idx -lt $hosts_lines.Count; $idx++) {
+        $entry = $hosts_lines[$idx]
+         # skip comment lines
+         if(-not $entry.Trim().StartsWith('#')) {
+            $entry_parts = Get-HostEntryParts -line $entry
+            if($entry_parts.success) {
+                $aliases_to_remove = @()
+                if($entry_parts.ip_address -eq $ip_address) {
+                    if($entry_parts.canonical_name -eq $canonical_name) {
+                        # don't need to worry about line being removed since canonical_name is present
+                        $entry_idx = $idx
+
+                        if($action -eq 'set') {
+                            # remove the entry's aliases that are not in $aliases
+                            $aliases_to_remove = $entry_parts.aliases | Where-Object { $aliases -notcontains $_ }
+                        } elseif($action -eq 'remove') {
+                            $aliases_to_remove = $aliases
+                        }
+                    } else {
+                        # this is the right ip_address, but not the cname we were looking for.
+                        # we need to make sure none of aliases or canonical_name exist for this entry
+                        # since the given canonical_name should be an A/AAAA record,
+                        # and aliases should be cname records for the canonical_name.
+                        $aliases_to_remove = $aliases + $canonical_name
+                    }
+                } else {
+                    # this is not the ip_address we are looking for
+                    if ($ip_address_type -eq $entry_parts.ip_type) {
+                        if ($entry_parts.canonical_name -eq $canonical_name) {
+                            # remove the entry
+                            if (Remove-HostEntry -list $hosts_lines -idx $idx){
+                                # keep index correct if we removed the line
+                                $idx = $idx - 1
+                            }
+                            if ($action -ne "set") {
+                                # keep old aliases intact
+                                $aliases_to_keep += $entry_parts.aliases | Where-Object { ($aliases + $aliases_to_keep + $canonical_name) -notcontains $_ }
+                            }
+                        } elseif ($action -eq "remove") {
+                            # just remove canonical_name. user may want alias(es) mapped to this canonical name
+                            $aliases_to_remove = $canonical_name
+                        } elseif ($aliases -contains $entry_parts.canonical_name) {
+                            # remove the entry
+                            if (Remove-HostEntry -list $hosts_lines -idx $idx) {
+                                # keep index correct if we removed the line
+                                $idx = $idx - 1
+                            }
+                            if ($action -eq "add") {
+                                # keep old aliases intact
+                                $aliases_to_keep += $entry_parts.aliases | Where-Object { ($aliases + $aliases_to_keep + $canonical_name) -notcontains $_ }
+                            }
+                        } else {
+                            # ensure canonical_name and aliases removed from this entry
+                            $aliases_to_remove = $aliases + $canonical_name
+                        }
+                    } else {
+                        # Just ignore if the types don't match.
+                        # TODO: Better ipv6 support. There is odd behavior for when an alias can be used for both ipv6 and ipv4
+                    }
+                }
+
+                if($aliases_to_remove) {
+                    if((Remove-HostnamesFromEntry -list $hosts_lines -idx $idx -aliases $aliases_to_remove).line_removed) {
+                        # keep index correct if we removed the line
+                        $idx = $idx - 1
+                    }
+                }
+            }
+        }
+    }
+
+    if($entry_idx -ge 0) {
+        # we found the entry
+        $aliases_to_add = @()
+        $entry_parts = Get-HostEntryParts -line $hosts_lines[$entry_idx]
+        if($action -eq 'remove') {
+            # just preserve any previously removed aliases
+            $aliases_to_add = $aliases_to_keep | Where-Object { $entry_parts.aliases -notcontains $_ }
+        } else {
+            # we want to add provided aliases and previously removed aliases that are not already in the list
+            $aliases_to_add = ($aliases + $aliases_to_keep) | Where-Object { $entry_parts.aliases -notcontains $_ }
+        }
+
+        if($aliases_to_add) {
+            Add-AliasesToEntry -list $hosts_lines -idx $entry_idx -aliases $aliases_to_add
+        }
+    } else {
+        # add the entry at the end
+        if($action -eq 'remove') {
+            if($aliases_to_keep) {
+                Add-HostEntry -list $hosts_lines -ip $ip_address -cname $canonical_name -aliases $aliases_to_keep
+            } else {
+                Add-HostEntry -list $hosts_lines -ip $ip_address -cname $canonical_name
+            }
+        } else {
+            Add-HostEntry -list $hosts_lines -ip $ip_address -cname $canonical_name -aliases ($aliases + $aliases_to_keep)
+        }
+    }
+}
+
+if( $result.changed -and -not $check_mode ) {
+    Set-Content -LiteralPath $hosts_file.FullName -Value $hosts_lines
+}
+
+Exit-Json $result

lib/ansible/modules/windows/win_hosts.py

@@ -0,0 +1,118 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+
+# Copyright: (c) 2018, Micah Hunsberger (@mhunsber)
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+# this is a windows documentation stub.  actual code lives in the .ps1
+# file of the same name
+
+ANSIBLE_METADATA = {'metadata_version': '1.1',
+                    'status': ['preview'],
+                    'supported_by': 'community'}
+
+DOCUMENTATION = r'''
+---
+module: win_hosts
+version_added: '2.8'
+short_description: Manages hosts file entries on Windows.
+description:
+  - Manages hosts file entries on Windows.
+  - Maps IPv4 or IPv6 addresses to canonical names
+  - Adds, removes, or sets cname records for ip and hostname pairs
+  - Modifies %windir%\system32\drivers\etc\hosts.
+options:
+  state:
+    description:
+      - Whether the entry should be present or absent.
+      - If only C(canonical_name) is provided when C(state=absent), then
+        all hosts entries with the canonical name of I(canonical_name)
+        will be removed.
+      - If only C(ip_address) is provided when C(state=absent), then all
+        hosts entries with the ip address of I(ip_address) will be removed.
+      - If C(ip_address) and C(canonical_name) are both omitted when
+        C(state=absent), then all hosts entries will be removed.
+    choices:
+      - absent
+      - present
+    default: present
+  canonical_name:
+    description:
+      - A canonical name for the host entry.
+      - required for C(state=present).
+  ip_address:
+    description:
+      - The ip address for the host entry.
+      - Can be either IPv4 (A record) or IPv6 (AAAA record).
+      - Required for C(state=present).
+  aliases:
+    description:
+      - A list of additional names (cname records) for the host entry.
+      - Only applicable when C(state=present).
+  action:
+    choices:
+      - add
+      - remove
+      - set
+    description:
+      - Controls the behavior of C(aliases).
+      - Only applicable when C(state=present).
+      - If C(add), each alias in I(aliases) will be added to the host entry.
+      - If C(set), each alias in I(aliases) will be added to the host entry,
+        and other aliases will be removed from the entry.
+    default: set
+author:
+  - Micah Hunsberger (@mhunsber)
+notes:
+  - Each canonical name can only be mapped to one IPv4 and one IPv6 address.
+    If C(canonical_name) is provided with C(state=present) and is found
+    to be mapped to another IP address that is the same type as, but unique
+    from C(ip_address), then C(canonical_name) and all C(aliases) will
+    be removed from the entry and added to an entry with the provided IP address.
+  - Each alias can only be mapped to one canonical name. If C(aliases) is provided
+    with C(state=present) and an alias is found to be mapped to another canonical
+    name, then the alias will be removed from the entry and added to or removed
+    from (based on I(action)) an entry with the provided canonical name.
+  - See also M(win_template), M(win_file), M(win_copy)
+'''
+
+EXAMPLES = r'''
+- name: Add 127.0.0.1 as an A record for localhost
+  win_hosts:
+    state: present
+    canonical_name: localhost
+    ip_address: 127.0.0.1
+
+- name: Add ::1 as an AAAA record for localhost
+  win_environment:
+    state: present
+    canonical_name: localhost
+    ip_address: '::1'
+
+- name: Remove 'bar' and 'zed' from the list of aliases for foo (192.168.1.100)
+  win_hosts:
+    state: present
+    canoncial_name: foo
+    ip_address: 192.168.1.100
+    action: remove
+    aliases:
+      - bar
+      - zed
+
+- name: Remove hosts entries with canonical name 'bar'
+  win_hosts:
+    state: absent
+    canonical_name: bar
+
+- name: Remove 10.2.0.1 from the list of hosts
+  win_hosts:
+    state: absent
+    ip_address: 10.2.0.1
+
+- name: Ensure all name resolution is handled by DNS
+  win_hosts:
+    state: absent
+'''
+
+RETURN = r'''
+'''

test/integration/targets/win_hosts/aliases

@@ -0,0 +1 @@
+shippable/windows/group3

test/integration/targets/win_hosts/defaults/main.yml

@@ -0,0 +1,13 @@
+---
+test_win_hosts_cname: testhost
+test_win_hosts_ip: 192.168.168.1
+
+test_win_hosts_aliases_set:
+  - alias1
+  - alias2
+  - alias3
+  - alias4
+
+test_win_hosts_aliases_remove:
+  - alias3
+  - alias4

test/integration/targets/win_hosts/meta/main.yml

@@ -0,0 +1,2 @@
+dependencies:
+- setup_remote_tmp_dir

test/integration/targets/win_hosts/tasks/main.yml

@@ -0,0 +1,17 @@
+---
+- name: take a copy of the original hosts file
+  win_copy:
+    src: C:\Windows\System32\drivers\etc\hosts
+    dest: '{{ remote_tmp_dir }}\hosts'
+    remote_src: yes
+
+- block:
+  - name: run tests
+    include_tasks: tests.yml
+
+  always:
+  - name: restore hosts file
+    win_copy:
+      src: '{{ remote_tmp_dir }}\hosts'
+      dest: C:\Windows\System32\drivers\etc\hosts
+      remote_src: yes

test/integration/targets/win_hosts/tasks/tests.yml

@@ -0,0 +1,189 @@
+---
+
+- name: add a simple host with address
+  win_hosts:
+    state: present
+    ip_address: "{{ test_win_hosts_ip }}"
+    canonical_name: "{{ test_win_hosts_cname }}"
+  register: add_ip
+
+- assert:
+    that:
+      - "add_ip.changed == true"
+
+- name: get actual dns result
+  win_shell: "try{ [array]$t = [Net.DNS]::GetHostEntry('{{ test_win_hosts_cname }}') } catch { return 'false' } if ($t[0].HostName -eq '{{ test_win_hosts_cname }}' -and $t[0].AddressList[0].toString() -eq '{{ test_win_hosts_ip }}'){ return 'true' } else { return 'false' }"
+  register: add_ip_actual
+
+- assert:
+    that:
+      - "add_ip_actual.stdout_lines[0]|lower == 'true'"
+
+- name: add a simple host with ipv4 address (idempotent)
+  win_hosts:
+    state: present
+    ip_address: "{{ test_win_hosts_ip }}"
+    canonical_name: "{{ test_win_hosts_cname }}"
+  register: add_ip
+
+- assert:
+    that:
+      - "add_ip.changed == false"
+
+- name: remove simple host
+  win_hosts:
+    state: absent
+    ip_address: "{{ test_win_hosts_ip }}"
+    canonical_name: "{{ test_win_hosts_cname }}"
+  register: remove_ip
+
+- assert:
+    that:
+      - "remove_ip.changed == true"
+
+- name: get actual dns result
+  win_shell: "try{ [array]$t = [Net.DNS]::GetHostEntry('{{ test_win_hosts_cname}}') } catch { return 'false' } if ($t[0].HostName -eq '{{ test_win_hosts_cname }}' -and $t[0].AddressList[0].toString() -eq '{{ test_win_hosts_ip }}'){ return 'true' } else { return 'false' }"
+  register: remove_ip_actual
+  failed_when: "remove_ip_actual.rc == 0"
+
+- assert:
+    that:
+      - "remove_ip_actual.stdout_lines[0]|lower == 'false'"
+
+- name: remove simple host (idempotent)
+  win_hosts:
+    state: absent
+    ip_address: "{{ test_win_hosts_ip }}"
+    canonical_name: "{{ test_win_hosts_cname }}"
+  register: remove_ip
+
+- assert:
+    that:
+      - "remove_ip.changed == false"
+
+- name: add host and set aliases
+  win_hosts:
+    state: present
+    ip_address: "{{ test_win_hosts_ip }}"
+    canonical_name: "{{ test_win_hosts_cname }}"
+    aliases: "{{ test_win_hosts_aliases_set | union(test_win_hosts_aliases_remove) }}"
+    action: set
+  register: set_aliases
+
+- assert:
+    that:
+      - "set_aliases.changed == true"
+
+- name: get actual dns result for host
+  win_shell: "try{ [array]$t = [Net.DNS]::GetHostEntry('{{ test_win_hosts_cname }}') } catch { return 'false' } if ($t[0].HostName -eq '{{ test_win_hosts_cname }}' -and $t[0].AddressList[0].toString() -eq '{{ test_win_hosts_ip }}'){ return 'true' } else { return 'false' }"
+  register: set_aliases_actual_host
+
+- assert:
+    that:
+      - "set_aliases_actual_host.stdout_lines[0]|lower == 'true'"
+
+- name: get actual dns results for aliases
+  win_shell: "try{ [array]$t = [Net.DNS]::GetHostEntry('{{ item }}') } catch { return 'false' } if ($t[0].HostName -eq '{{ test_win_hosts_cname }}' -and $t[0].AddressList[0].toString() -eq '{{ test_win_hosts_ip }}'){ return 'true' } else { return 'false' }"
+  register: set_aliases_actual
+  with_items: "{{ test_win_hosts_aliases_set | union(test_win_hosts_aliases_remove) }}"
+
+- assert:
+    that:
+      - "item.stdout_lines[0]|lower == 'true'"
+  with_items: "{{ set_aliases_actual.results }}"
+
+- name: add host and set aliases (idempotent)
+  win_hosts:
+    state: present
+    ip_address: "{{ test_win_hosts_ip }}"
+    canonical_name: "{{ test_win_hosts_cname }}"
+    aliases: "{{ test_win_hosts_aliases_set | union(test_win_hosts_aliases_remove) }}"
+    action: set
+  register: set_aliases
+
+- assert:
+    that:
+      - "set_aliases.changed == false"
+
+- name: remove aliases from the list
+  win_hosts:
+    state: present
+    ip_address: "{{ test_win_hosts_ip }}"
+    canonical_name: "{{ test_win_hosts_cname }}"
+    aliases: "{{ test_win_hosts_aliases_remove }}"
+    action: remove
+  register: remove_aliases
+
+- assert:
+    that:
+      - "remove_aliases.changed == true"
+
+- name: get actual dns result for removed aliases
+  win_shell: "try{ [array]$t = [Net.DNS]::GetHostEntry('{{ item }}') } catch { return 'false' } if ($t[0].HostName -eq '{{ test_win_hosts_cname }}' -and $t[0].AddressList[0].toString() -eq '{{ test_win_hosts_ip }}'){ return 'true' } else { return 'false' }"
+  register: remove_aliases_removed_actual
+  failed_when: "remove_aliases_removed_actual.rc == 0"
+  with_items: "{{ test_win_hosts_aliases_remove }}"
+
+- assert:
+    that:
+      - "item.stdout_lines[0]|lower == 'false'"
+  with_items: "{{ remove_aliases_removed_actual.results }}"
+
+- name: get actual dns result for remaining aliases
+  win_shell: "try{ [array]$t = [Net.DNS]::GetHostEntry('{{ item }}') } catch { return 'false' } if ($t[0].HostName -eq '{{ test_win_hosts_cname }}' -and $t[0].AddressList[0].toString() -eq '{{ test_win_hosts_ip }}'){ return 'true' } else { return 'false' }"
+  register: remove_aliases_remain_actual
+  with_items: "{{ test_win_hosts_aliases_set | difference(test_win_hosts_aliases_remove) }}"
+
+- assert:
+    that:
+      - "item.stdout_lines[0]|lower == 'true'"
+  with_items: "{{ remove_aliases_remain_actual.results }}"
+
+- name: remove aliases from the list (idempotent)
+  win_hosts:
+    state: present
+    ip_address: "{{ test_win_hosts_ip }}"
+    canonical_name: "{{ test_win_hosts_cname }}"
+    aliases: "{{ test_win_hosts_aliases_remove }}"
+    action: remove
+  register: remove_aliases
+
+- assert:
+    that:
+      - "remove_aliases.changed == false"
+
+- name: add aliases back
+  win_hosts:
+    state: present
+    ip_address: "{{ test_win_hosts_ip }}"
+    canonical_name: "{{ test_win_hosts_cname }}"
+    aliases: "{{ test_win_hosts_aliases_remove }}"
+    action: add
+  register: add_aliases
+
+- assert:
+    that:
+      - "add_aliases.changed == true"
+
+- name: get actual dns results for aliases
+  win_shell: "try{ [array]$t = [Net.DNS]::GetHostEntry('{{ item }}') } catch { return 'false' } if ($t[0].HostName -eq '{{ test_win_hosts_cname }}' -and $t[0].AddressList[0].toString() -eq '{{ test_win_hosts_ip }}'){ return 'true' } else { return 'false' }"
+  register: add_aliases_actual
+  with_items: "{{ test_win_hosts_aliases_set | union(test_win_hosts_aliases_remove) }}"
+
+- assert:
+    that:
+      - "item.stdout_lines[0]|lower == 'true'"
+  with_items: "{{ add_aliases_actual.results }}"
+
+- name: add aliases back (idempotent)
+  win_hosts:
+    state: present
+    ip_address: "{{ test_win_hosts_ip }}"
+    canonical_name: "{{ test_win_hosts_cname }}"
+    aliases: "{{ test_win_hosts_aliases_remove }}"
+    action: add
+  register: add_aliases
+
+- assert:
+    that:
+      - "add_aliases.changed == false"