From e2b879caff26e6dcb81412640f40767863831f66 Mon Sep 17 00:00:00 2001
From: alex <alex@pdp7.net>
Date: Wed, 1 Feb 2023 21:30:55 +0100
Subject: [PATCH] Document ugly things

---
 personal_infra/pseudo_resource_exporter.py | 26 ++++++++++++++++--
 personal_infra/up.py                       | 31 ++++++++++++++++++++--
 2 files changed, 53 insertions(+), 4 deletions(-)

diff --git a/personal_infra/pseudo_resource_exporter.py b/personal_infra/pseudo_resource_exporter.py
index 0753a0d..793f2b7 100755
--- a/personal_infra/pseudo_resource_exporter.py
+++ b/personal_infra/pseudo_resource_exporter.py
@@ -1,17 +1,37 @@
 #!/usr/bin/env python3
-
 import json
 import pathlib
 
 
+"""
+This is an ugly hack.
+
+Puppet exported resources are very nice to generate monitoring configuration
+along with your Puppet resources. As you define something like an Apache
+virtual host, you can create a Nagios service check for it.
+
+But this requires a PuppetDB, and does not play nice with having no central
+Puppet infra.
+
+With its sibling script up.py, this script takes the JSON files generated by
+that, and manipulates them. This script moves Nagios resources to a specific
+host and does ugly trickery to fool Puppet into accepting that.
+
+This is like exported resources, but you don't need to declare a resource as
+exported.
+"""
+
+
 def load_json(path):
     with open(path) as f:
         return json.load(f)
 
+
 def save_json(r, path):
     with open(path, "w") as f:
         json.dump(r, f)
 
+
 nagios_catalog_file = pathlib.Path("build/puppet/build/output/nagios.h1.int.pdp7.net/catalog.json")
 
 if nagios_catalog_file.exists():
@@ -32,6 +52,7 @@ if nagios_catalog_file.exists():
 nagios_resources = []
 nagios_edge_targets = []
 
+
 def is_nagios_resource(r):
     return r["type"].startswith("Nagios")
 
@@ -39,6 +60,7 @@ def is_nagios_resource(r):
 def is_nagios_edge(e):
     return e["target"].startswith("Nagios")
 
+
 for catalog_file in catalog_files:
     if catalog_file == nagios_catalog_file:
         continue
@@ -48,7 +70,7 @@ for catalog_file in catalog_files:
     nagios_edge_targets += [e["target"] for e in catalog["edges"] if is_nagios_edge(e)]
     catalog["edges"] = [e for e in catalog["edges"] if not is_nagios_edge(e)]
     save_json(catalog, catalog_file)
-    
+
 
 if nagios_catalog_file.exists():
     nagios_contact_position = nagios_catalog["resources"].index(nagios_contact)
diff --git a/personal_infra/up.py b/personal_infra/up.py
index 55d0f9b..131fc9e 100755
--- a/personal_infra/up.py
+++ b/personal_infra/up.py
@@ -8,17 +8,44 @@ import subprocess
 import textwrap
 import yaml
 
+
 """
+This script performs Puppet catalog compilation without a central server.
+
+It receives the following arguments:
+
+* directory: a working directory. The script expects to find some data, like
+  variables to use in the compilation process, facts, etc. The script also
+  generates intermediate files and output there.
+
+* modulepath: path to your modules directory
+* manifest: path to your site directory
+* host: the hosts to compile catalogs to
+
+The script expects the following content on the working directory:
+
 directory/
   global_vars/*.json: these JSON files will be available to all hosts
   host_vars/{host}/*.json: these JSON files will be available in each host
   facts/{host}.json: output from "facter -y" for each host
 
+And produces the following files:
+
 directory/
   output/
     {host}/
-      catalog.json
-      modules/
+      catalog.json: the compiled catalog for the host
+      modules: a copy of the module directory
+
+Just ship the {host} directory to each host and run:
+
+$ puppet apply --catalog .../catalog.json --modulepath=.../modules/
+
+Check the apply_catalog Ansible role for example usage.
+
+As we have the catalogs, we can manipulate them. See
+pseudo_resource_exporter.py for an example hack. We can simulate exported
+resources without PuppetDB.
 """
 
 
-- 
2.47.3