[constructed-inventory] Allow filtering based on facts (#13678)

* initial functional filter-on-facts functionality

* Move facts to its own module to make interface more coherent

* Update test

awx/main/tasks/facts.py

@@ -0,0 +1,126 @@
+import codecs
+import datetime
+import os
+import json
+import logging
+
+# Django
+from django.conf import settings
+from django.db.models.query import QuerySet
+from django.utils.encoding import smart_str
+from django.utils.timezone import now
+
+# AWX
+from awx.main.utils.common import log_excess_runtime
+
+
+logger = logging.getLogger('awx.main.tasks.facts')
+system_tracking_logger = logging.getLogger('awx.analytics.system_tracking')
+
+
+def _get_inventory_hosts(inventory, slice_number, slice_count, only=('name', 'ansible_facts', 'ansible_facts_modified', 'modified', 'inventory_id'), **filters):
+    """Return value is an iterable for the relevant hosts for this job"""
+    if not inventory:
+        return []
+    host_queryset = inventory.hosts.only(*only)
+    if filters:
+        host_queryset = host_queryset.filter(**filters)
+    host_queryset = inventory.get_sliced_hosts(host_queryset, slice_number, slice_count)
+    if isinstance(host_queryset, QuerySet):
+        return host_queryset.iterator()
+    return host_queryset
+
+
+@log_excess_runtime(logger, debug_cutoff=0.01, msg='Inventory {inventory_id} host facts prepared for {written_ct} hosts, took {delta:.3f} s', add_log_data=True)
+def start_fact_cache(inventory, destination, log_data, timeout=None, slice_number=0, slice_count=1):
+    log_data['inventory_id'] = inventory.id
+    log_data['written_ct'] = 0
+    try:
+        os.makedirs(destination, mode=0o700)
+    except FileExistsError:
+        pass
+
+    if timeout is None:
+        timeout = settings.ANSIBLE_FACT_CACHE_TIMEOUT
+    if timeout > 0:
+        # exclude hosts with fact data older than `settings.ANSIBLE_FACT_CACHE_TIMEOUT seconds`
+        timeout = now() - datetime.timedelta(seconds=timeout)
+        hosts = _get_inventory_hosts(inventory, slice_number, slice_count, ansible_facts_modified__gte=timeout)
+    else:
+        hosts = _get_inventory_hosts(inventory, slice_number, slice_count)
+
+    last_filepath_written = None
+    for host in hosts:
+        filepath = os.sep.join(map(str, [destination, host.name]))
+        if not os.path.realpath(filepath).startswith(destination):
+            system_tracking_logger.error('facts for host {} could not be cached'.format(smart_str(host.name)))
+            continue
+        try:
+            with codecs.open(filepath, 'w', encoding='utf-8') as f:
+                os.chmod(f.name, 0o600)
+                json.dump(host.ansible_facts, f)
+                log_data['written_ct'] += 1
+                last_filepath_written = filepath
+        except IOError:
+            system_tracking_logger.error('facts for host {} could not be cached'.format(smart_str(host.name)))
+            continue
+    # make note of the time we wrote the last file so we can check if any file changed later
+    if last_filepath_written:
+        return os.path.getmtime(last_filepath_written)
+    return None
+
+
+@log_excess_runtime(
+    logger,
+    debug_cutoff=0.01,
+    msg='Inventory {inventory_id} host facts: updated {updated_ct}, cleared {cleared_ct}, unchanged {unmodified_ct}, took {delta:.3f} s',
+    add_log_data=True,
+)
+def finish_fact_cache(inventory, destination, facts_write_time, log_data, slice_number=0, slice_count=1, job_id=None):
+    log_data['inventory_id'] = inventory.id
+    log_data['updated_ct'] = 0
+    log_data['unmodified_ct'] = 0
+    log_data['cleared_ct'] = 0
+    hosts_to_update = []
+    for host in _get_inventory_hosts(inventory, slice_number, slice_count):
+        filepath = os.sep.join(map(str, [destination, host.name]))
+        if not os.path.realpath(filepath).startswith(destination):
+            system_tracking_logger.error('facts for host {} could not be cached'.format(smart_str(host.name)))
+            continue
+        if os.path.exists(filepath):
+            # If the file changed since we wrote the last facts file, pre-playbook run...
+            modified = os.path.getmtime(filepath)
+            if (not facts_write_time) or modified > facts_write_time:
+                with codecs.open(filepath, 'r', encoding='utf-8') as f:
+                    try:
+                        ansible_facts = json.load(f)
+                    except ValueError:
+                        continue
+                    host.ansible_facts = ansible_facts
+                    host.ansible_facts_modified = now()
+                    hosts_to_update.append(host)
+                    system_tracking_logger.info(
+                        'New fact for inventory {} host {}'.format(smart_str(host.inventory.name), smart_str(host.name)),
+                        extra=dict(
+                            inventory_id=host.inventory.id,
+                            host_name=host.name,
+                            ansible_facts=host.ansible_facts,
+                            ansible_facts_modified=host.ansible_facts_modified.isoformat(),
+                            job_id=job_id,
+                        ),
+                    )
+                    log_data['updated_ct'] += 1
+            else:
+                log_data['unmodified_ct'] += 1
+        else:
+            # if the file goes missing, ansible removed it (likely via clear_facts)
+            host.ansible_facts = {}
+            host.ansible_facts_modified = now()
+            hosts_to_update.append(host)
+            system_tracking_logger.info('Facts cleared for inventory {} host {}'.format(smart_str(host.inventory.name), smart_str(host.name)))
+            log_data['cleared_ct'] += 1
+        if len(hosts_to_update) > 100:
+            inventory.hosts.bulk_update(hosts_to_update, ['ansible_facts', 'ansible_facts_modified'])
+            hosts_to_update = []
+    if hosts_to_update:
+        inventory.hosts.bulk_update(hosts_to_update, ['ansible_facts', 'ansible_facts_modified'])