From cb0ae89c6c220b8a6098b587f4660b3ea94d5f32 Mon Sep 17 00:00:00 2001
From: John Lotoski <john.lotoski@iohk.io>
Date: Tue, 16 Jan 2024 20:55:34 -0600
Subject: [PATCH] postgres: add a config.socketDir option

* Defaults to config.dataDir
* Allows customization of socketDir for users who do not wish it fixed
  to dataDir
* Sockets are limited to around [100 chars](https://linux.die.net/man/7/unix):
  * In the case that the default or desired dataDir absolute path exceeds
    this char limit, postgres will fail to start if it is also used for
    socketDir
  * In this case, dataDir can remain as desired and socketDir can be set
    separately to a shorter absolute path
---
 nix/postgres/default.nix      | 15 +++++++++++----
 nix/postgres/setup-script.nix |  2 +-
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/nix/postgres/default.nix b/nix/postgres/default.nix
index 30590720..4118c776 100644
--- a/nix/postgres/default.nix
+++ b/nix/postgres/default.nix
@@ -50,6 +50,12 @@ in
       description = "The DB data directory";
     };
 
+    socketDir = lib.mkOption {
+      type = lib.types.str;
+      default = config.dataDir;
+      description = "The DB socket directory";
+    };
+
     hbaConf =
       let
         hbaConfSubmodule = lib.types.submodule {
@@ -161,7 +167,7 @@ in
         default = {
           listen_addresses = config.listen_addresses;
           port = config.port;
-          unix_socket_directories = config.dataDir;
+          unix_socket_directories = config.socketDir;
           hba_file = "${config.hbaConfFile}";
         };
       };
@@ -181,7 +187,7 @@ in
         default = {
           listen_addresses = config.listen_addresses;
           port = config.port;
-          unix_socket_directories = lib.mkDefault config.dataDir;
+          unix_socket_directories = lib.mkDefault config.socketDir;
           hba_file = "${config.hbaConfFile}";
         };
         example = lib.literalExpression ''
@@ -311,12 +317,13 @@ in
                   text = ''
                     set -euo pipefail
                     PGDATA=$(readlink -f "${config.dataDir}")
+                    PGSOCKETDIR=$(readlink -f "${config.socketDir}")
                     export PGDATA
-                    postgres -k "$PGDATA"
+                    postgres -k "$PGSOCKETDIR"
                   '';
                 };
                 pg_isreadyArgs = [
-                  "-h $(readlink -f ${config.dataDir})"
+                  "-h $(readlink -f \"${config.socketDir}\")"
                   "-p ${toString config.port}"
                   "-d template1"
                 ] ++ (lib.optional (config.superuser != null) "-U ${config.superuser}");
diff --git a/nix/postgres/setup-script.nix b/nix/postgres/setup-script.nix
index 06f0e2c4..94928007 100644
--- a/nix/postgres/setup-script.nix
+++ b/nix/postgres/setup-script.nix
@@ -100,7 +100,7 @@ in
       echo
       echo "PostgreSQL is setting up the initial database."
       echo
-      PGHOST=$(mktemp -d "$(readlink -f ${config.dataDir})/pg-init-XXXXXX")
+      PGHOST=$(mkdir -p "${config.socketDir}" && mktemp -d "$(readlink -f "${config.socketDir}")/pg-init-XXXXXX")
       export PGHOST
 
       function remove_tmp_pg_init_sock_dir() {