Close DB connections once forked processes have completed (nautobot#471)

* Fix issue with DB connections not closing

* Update development/Dockerfile-fakenos

Co-authored-by: Gary Snider <75227981+gsnider2195@users.noreply.github.com>

* Update development/Dockerfile-fakenos

Co-authored-by: Gary Snider <75227981+gsnider2195@users.noreply.github.com>

* Add fakenos documentation

---------

Co-authored-by: Gary Snider <75227981+gsnider2195@users.noreply.github.com>

Author: 2 people

changes/366.fixed

@@ -0,0 +1 @@
+Fixed Sync Devices and Sync Network Data jobs not releasing DB connections.

development/Dockerfile-fakenos

@@ -0,0 +1,34 @@
+# Fakenos dockerfile for local development
+
+# Accepts a desired Python version as build argument, default to 3.12
+ARG PYTHON_VER="3.12"
+
+FROM docker.io/python:${PYTHON_VER}-slim
+
+WORKDIR /usr/src/fakenos
+
+RUN apt-get update && apt-get install -y --no-install-recommends git && rm -rf /var/lib/apt/lists/*
+
+RUN pip install git+https://github.com/fakenos/fakenos.git
+
+# NOTE: fakenos does not recognize .yml files, must use .yaml
+RUN cat <<EOF > /usr/src/fakenos/fakenos_inventory.yaml
+hosts:
+  fakerouter:
+    username: admin
+    password: admin
+    platform: cisco_ios
+    server:
+      plugin: "ParamikoSshServer"
+      configuration:
+        address: "0.0.0.0"
+        timeout: 1
+    port: 22
+EOF
+
+ARG PYTHON_VER="3.12"
+
+# NOTE: fakenos does not correctly handle absolute paths
+WORKDIR /usr/local/lib/python${PYTHON_VER}/site-packages
+
+CMD [ "fakenos", "--inventory", "/usr/src/fakenos/fakenos_inventory.yaml" ]

development/docker-compose.fakenos.yml

@@ -0,0 +1,28 @@
+---
+services:
+  fakerouter1:
+    build:
+      args:
+        PYTHON_VER: "${PYTHON_VER}"
+      context: "../"
+      dockerfile: "development/Dockerfile-fakenos"
+    image: "nautobot-device-onboarding/fakenos:py${PYTHON_VER}"
+    pull_policy: "never"
+    expose:
+      - "22"
+  fakerouter2: &fakerouter
+    image: "nautobot-device-onboarding/fakenos:py${PYTHON_VER}"
+    pull_policy: "never"
+    expose:
+      - "22"
+  fakerouter3: *fakerouter
+  fakerouter4: *fakerouter
+  fakerouter5: *fakerouter
+  fakerouter6: *fakerouter
+  fakerouter7: *fakerouter
+  fakerouter8: *fakerouter
+  fakerouter9: *fakerouter
+  fakerouter10: *fakerouter
+  fakerouter11: *fakerouter
+  fakerouter12: *fakerouter
+  fakerouter13: *fakerouter

docs/dev/dev_environment.md

@@ -22,6 +22,20 @@ The [Invoke](http://www.pyinvoke.org/) library is used to provide some helper co
 
 Using **Invoke** these configuration options can be overridden using [several methods](https://docs.pyinvoke.org/en/stable/concepts/configuration.html). Perhaps the simplest is setting an environment variable `INVOKE_NAUTOBOT_DEVICE_ONBOARDING_VARIABLE_NAME` where `VARIABLE_NAME` is the variable you are trying to override. The only exception is `compose_files`, because it is a list it must be overridden in a YAML file. There is an example `invoke.yml` (`invoke.example.yml`) in this directory which can be used as a starting point.
 
+#### FakeNOS Support
+
+To enable FakeNOS support in the development environment, you can add the `docker-compose.fakenos.yml` file to the list of compose files used by Invoke. This can be done by creating an `invoke.yml` file with the following contents at the root of the repo:
+
+```yaml
+---
+nautobot_device_onboarding:
+    compose_files:
+      - docker-compose.redis.yml
+      - docker-compose.postgres.yml
+      - docker-compose.fakenos.yml
+      - docker-compose.dev.yml
+```
+
 ### Docker Development Environment
 
 !!! tip

nautobot_device_onboarding/nornir_plays/command_getter.py

@@ -32,7 +32,11 @@
     get_git_repo_parser_path,
     load_files_with_precedence,
 )
-from nautobot_device_onboarding.utils.helper import check_for_required_file, format_log_message
+from nautobot_device_onboarding.utils.helper import (
+    check_for_required_file,
+    close_threaded_db_connections,
+    format_log_message,
+)
 
 PARSER_DIR = os.path.abspath(os.path.join(os.path.dirname(os.path.dirname(__file__)), "parsers"))
 
@@ -114,6 +118,7 @@ def _get_commands_to_run(yaml_parsed_info, sync_vlans, sync_vrfs, sync_cables, s
     return deduplicate_command_list(all_commands)
 
 
+@close_threaded_db_connections
 def netmiko_send_commands(task: Task, command_getter_yaml_data: Dict, command_getter_job: str, logger, nautobot_job):
     """Run commands specified in PLATFORM_COMMAND_MAP."""
     if not task.host.platform:

nautobot_device_onboarding/nornir_plays/processor.py

@@ -9,6 +9,7 @@
 
 from nautobot_device_onboarding.nornir_plays.formatter import extract_show_data
 from nautobot_device_onboarding.nornir_plays.schemas import NETWORK_DATA_SCHEMA, NETWORK_DEVICES_SCHEMA
+from nautobot_device_onboarding.utils.helper import close_threaded_db_connections
 
 
 class CommandGetterProcessor(BaseLoggingProcessor):
@@ -29,6 +30,7 @@ def task_instance_started(self, task: Task, host: Host) -> None:
                 "network_driver": host.platform,
             }
 
+    @close_threaded_db_connections
     def task_instance_completed(self, task: Task, host: Host, result: MultiResult) -> None:
         """Processor for logging and data processing on task completed.
 

nautobot_device_onboarding/utils/helper.py

@@ -5,6 +5,7 @@
 import socket
 
 import netaddr
+from django.db import connections
 from nautobot.dcim.filters import DeviceFilterSet
 from nautobot.dcim.models import Device
 from netaddr.core import AddrFormatError
@@ -119,3 +120,15 @@ def check_for_required_file(directory, filename):
         return False
     except FileNotFoundError:
         return False
+
+
+def close_threaded_db_connections(func):
+    """Decorator to close database connections in threaded tasks."""
+
+    def inner(*args, **kwargs):
+        try:
+            func(*args, **kwargs)
+        finally:
+            connections.close_all()
+
+    return inner