From a6bd0b4b77bd3054bfefa9eb7ea9b671177e95e5 Mon Sep 17 00:00:00 2001
From: "Karl O. Pinc" <kop@karlpinc.com>
Date: Fri, 15 Sep 2023 15:03:24 -0500
Subject: [PATCH] New targets for comparing db configurations

---
 .gitignore            |  3 +++
 make_files/make_db.mk | 25 ++++++++++++++++++++++++-
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/.gitignore b/.gitignore
index e5c365e..5f193e0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,6 +7,9 @@ db/psql_setup.sh
 db/run_createdb.sh
 db/set_timezone.sh
 
+# A generated dump of the settings
+db/pg_settings.new
+
 # Built image files
 doc/images/
 
diff --git a/make_files/make_db.mk b/make_files/make_db.mk
index 7ea2548..f3561ac 100644
--- a/make_files/make_db.mk
+++ b/make_files/make_db.mk
@@ -583,6 +583,7 @@ CREATE_ADMINUSER := CREATE ROLE $(TARGET_ROLE) LOGIN CREATEDB CREATEROLE \
 DROP_PUBLIC := DROP SCHEMA public RESTRICT;
 DROP_THROWAWAYDB := DROP DATABASE $(THROWAWAY_DB);
 SET_PASSWORD := ALTER ROLE $(TARGET_ROLE) PASSWORD '$(NEW_PASSWORD)'
+GET_PG_SETTINGS := SELECT name, setting, unit FROM pg_settings ORDER BY name;
 
 ##
 ## The available targets for make (make TARGET) are:
@@ -686,12 +687,34 @@ drop-public:
 # SUPERUSER or by the postgres user.  PG v15 introduced the
 # pg_database_owner pre-defined role and database owners can drop the
 # public schema.
-
 .PHONY: drop-public-root
 drop-public-root:
 	printf '$(DROP_PUBLIC)\n' \
 	  | su postgres -c 'psql -h $(HOST) -d $(TARGET_DB) -q -U postgres'
 
+##   db/pg_settings.new
+##                      Save a file of all the configuration settings
+##                      of the TARGET_DB.  See the "compare-db" target.
+##                      After changing a setting, create "db/pg_settings.new"
+##                      and then rename it to "db/pg_settings" and commit
+##                      the change to revision control.
+.PHONY: db/pg_settings.new
+db/pg_settings.new:
+	printf '$(GET_PG_SETTINGS)\n' \
+	  | psql $(PSQL_ARGS_MINIMAL) --tuples-only \
+	  > db/pg_settings.new
+
+##   compare-db-settings
+##                      Diff the configuration settings of the TARGET_DB
+##                      with those in the "db/pg_settings" file.
+##                      This ensures your database is configured as expected.
+##                      Before changing database settings run this target.
+.PHONY: compare-db-settings
+compare-db-settings:
+	printf '$(GET_PG_SETTINGS)\n' \
+	  | psql $(PSQL_ARGS_MINIMAL) --tuples-only \
+	  | diff -u db/pg_settings /dev/stdin
+
 ##
 ## Lesser used targets:
 ##
-- 
2.34.1