nmap: fix cache support (#2282) (#2328)

* add cache support

* pep8 e501 fix

* revert verify_file function

* revert description update

* add changelog fragment

Co-authored-by: Dennis Israelsson <github@mdh.nu>
(cherry picked from commit 31c9ed0fe6)

Co-authored-by: Dennis Israelsson <dennis.israelsson@gmail.com>

changelogs/fragments/2282-nmap-fix-cache-support.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - nmap inventory plugin - fix cache and constructed group support (https://github.com/ansible-collections/community.general/issues/2242).

plugins/inventory/nmap.py

@@ -72,6 +72,25 @@ class InventoryModule(BaseInventoryPlugin, Constructable, Cacheable):
         self._nmap = None
         super(InventoryModule, self).__init__()
 
+    def _populate(self, hosts):
+        # Use constructed if applicable
+        strict = self.get_option('strict')
+
+        for host in hosts:
+            hostname = host['name']
+            self.inventory.add_host(hostname)
+            for var, value in host.items():
+                self.inventory.set_variable(hostname, var, value)
+
+            # Composed variables
+            self._set_composite_vars(self.get_option('compose'), host, hostname, strict=strict)
+
+            # Complex groups based on jinja2 conditionals, hosts that meet the conditional are added to group
+            self._add_host_to_composed_groups(self.get_option('groups'), host, hostname, strict=strict)
+
+            # Create groups based on variable values and add the corresponding hosts to it
+            self._add_host_to_keyed_groups(self.get_option('keyed_groups'), host, hostname, strict=strict)
+
     def verify_file(self, path):
 
         valid = False
@@ -83,7 +102,7 @@ class InventoryModule(BaseInventoryPlugin, Constructable, Cacheable):
 
         return valid
 
-    def parse(self, inventory, loader, path, cache=False):
+    def parse(self, inventory, loader, path, cache=True):
 
         try:
             self._nmap = get_bin_path('nmap')
@@ -94,6 +113,25 @@ class InventoryModule(BaseInventoryPlugin, Constructable, Cacheable):
 
         self._read_config_data(path)
 
+        cache_key = self.get_cache_key(path)
+
+        # cache may be True or False at this point to indicate if the inventory is being refreshed
+        # get the user's cache option too to see if we should save the cache if it is changing
+        user_cache_setting = self.get_option('cache')
+
+        # read if the user has caching enabled and the cache isn't being refreshed
+        attempt_to_read_cache = user_cache_setting and cache
+        # update if the user has caching enabled and the cache is being refreshed; update this value to True if the cache has expired below
+        cache_needs_update = user_cache_setting and not cache
+
+        if attempt_to_read_cache:
+            try:
+                results = self._cache[cache_key]
+            except KeyError:
+                # This occurs if the cache_key is not in the cache or if the cache_key expired, so the cache needs to be updated
+                cache_needs_update = True
+
+        if cache_needs_update:
             # setup command
             cmd = [self._nmap]
             if not self._options['ports']:
@@ -122,6 +160,7 @@ class InventoryModule(BaseInventoryPlugin, Constructable, Cacheable):
                 host = None
                 ip = None
                 ports = []
+                results = []
 
                 try:
                     t_stdout = to_text(stdout, errors='surrogate_or_strict')
@@ -131,8 +170,8 @@ class InventoryModule(BaseInventoryPlugin, Constructable, Cacheable):
                 for line in t_stdout.splitlines():
                     hits = self.find_host.match(line)
                     if hits:
-                    if host is not None:
+                        if host is not None and ports:
-                        self.inventory.set_variable(host, 'ports', ports)
+                            results[-1]['ports'] = ports
 
                         # if dns only shows arpa, just use ip instead as hostname
                         if hits.group(1).endswith('.in-addr.arpa'):
@@ -148,21 +187,27 @@ class InventoryModule(BaseInventoryPlugin, Constructable, Cacheable):
 
                         if host is not None:
                             # update inventory
-                        self.inventory.add_host(host)
+                            results.append(dict())
-                        self.inventory.set_variable(host, 'ip', ip)
+                            results[-1]['name'] = host
+                            results[-1]['ip'] = ip
                             ports = []
                         continue
 
                     host_ports = self.find_port.match(line)
                     if host is not None and host_ports:
-                    ports.append({'port': host_ports.group(1), 'protocol': host_ports.group(2), 'state': host_ports.group(3), 'service': host_ports.group(4)})
+                        ports.append({'port': host_ports.group(1),
+                                      'protocol': host_ports.group(2),
+                                      'state': host_ports.group(3),
+                                      'service': host_ports.group(4)})
                         continue
 
-                # TODO: parse more data, OS?
-
                 # if any leftovers
                 if host and ports:
-                self.inventory.set_variable(host, 'ports', ports)
+                    results[-1]['ports'] = ports
 
             except Exception as e:
                 raise AnsibleParserError("failed to parse %s: %s " % (to_native(path), to_native(e)))
+
+            self._cache[cache_key] = results
+
+        self._populate(results)