always init pg database script in entrypoint

hosts/common/optional/docker/postgres.nix

@@ -1,6 +1,88 @@
 { pkgs, lib, inputs, config, ... }:
 let
   admin_dbPasswordFile = lib.optionalString (lib.hasAttr "sops-nix" inputs) config.sops.secrets."software/postgres/admin_db/password".path;
+  customEntryPointScript = pkgs.writeScript "custom-entrypoint.sh" ''
+    #!/usr/bin/env bash
+    ## copied from: https://github.com/docker-library/postgres/pull/496#issue-358838955
+    set -Eeo pipefail
+              
+    echo "🐘 custom-entry-point"
+    # Example using the functions of the postgres entrypoint to customize startup to always run files in /always-initdb.d/
+              
+    source "$(which docker-entrypoint.sh)"
+              
+    docker_setup_env
+    docker_create_db_directories
+    # assumption: we are already running as the owner of PGDATA
+              
+    # This is needed if the container is started as `root`
+    #if [ "$1" = 'postgres' ] && [ "$(id -u)" = '0' ]; then
+    if [ "$(id -u)" = '0' ]; then
+      exec gosu postgres "$BASH_SOURCE" "$@"
+    fi
+              
+              
+    if [ -z "$DATABASE_ALREADY_EXISTS" ]; then
+      echo "🐘 db is missing"
+      docker_verify_minimum_env
+      docker_init_database_dir
+      pg_setup_hba_conf
+              
+      # only required for '--auth[-local]=md5' on POSTGRES_INITDB_ARGS
+      export PGPASSWORD="''${PGPASSWORD:-$POSTGRES_PASSWORD}"
+              
+      docker_temp_server_start "$@" -c max_locks_per_transaction=256
+      docker_setup_db
+      docker_process_init_files /docker-entrypoint-initdb.d/*
+      docker_temp_server_stop
+    else
+      echo "🐘 db already exists"
+      docker_temp_server_start "$@"
+      docker_process_init_files /always-initdb.d/*
+      docker_temp_server_stop
+    fi
+              
+    echo "🐘 .. starting!"
+    exec postgres "$@"
+  '';
+
+  initScript = pkgs.writeScript "init.sh" ''
+    #!/bin/bash
+    function create_user_and_database() {
+      local database=$1
+      local user=$2
+      local extensions=$3
+      echo "### admin user: $POSTGRES_USER ###"
+      echo "  Creating database '$database'"
+      echo "  Creating user  '$user'"
+      psql -v --username "$POSTGRES_USER" -d "$POSTGRES_DB" <<-EOSQL
+          CREATE USER $user;
+          CREATE DATABASE $database;
+          GRANT ALL PRIVILEGES ON DATABASE $database TO $user;
+    EOSQL
+            
+    # Loop through extensions and create them
+    for ext in $(echo "$extensions" | tr ',' ' '); do
+      echo "     - Installing extention $ext"
+      psql -v --username "$POSTGRES_USER" -d "$database" -c "CREATE EXTENSION $ext;"
+    done
+    }
+            
+    if [ -n "$POSTGRES_MULTIPLE_DATABASES" ]; then
+            
+      # Parse the JSON string
+      database_names=$(echo "$POSTGRES_MULTIPLE_DATABASES" | jq -r '.[0] | keys[]')
+      echo "Multiple database creation requested: $(echo "$database_names" | tr "\n" " ")"
+              
+      # Loop through each database and create it
+      for db_name in $database_names; do
+        user=$(echo "$POSTGRES_MULTIPLE_DATABASES" | jq -r ".[0] | .''${db_name} | .user")
+        extensions=$(echo "$POSTGRES_MULTIPLE_DATABASES" | jq -r ".[0] | .''${db_name} | .extensions | join(\",\")")
+        create_user_and_database "$db_name" "$user" "$extensions"
+      done
+    fi
+  '';
+
 in
 {
   sops.secrets = {
@@ -20,7 +102,12 @@ in
                     postgresql-16-postgis \
                     jq \
                 && rm -rf /var/lib/apt/lists/*
+            RUN mkdir -p /scripts/ /always-initdb.d/
+            COPY ${builtins.baseNameOf customEntryPointScript} /scripts/custom-entrypoint.sh
+            RUN chmod -R a+x /scripts
+            ENTRYPOINT /scripts/custom-entrypoint.sh
           ''}";
+
         environment = {
           POSTGRES_PASSWORD_FILE = admin_dbPasswordFile;
           POSTGRES_USER = "admin";
@@ -55,8 +142,10 @@ in
               }
             ]
           '';
+
         };
         ports = [ "5432:5432" ];
+
         volumes = [
           "/mnt/postgres:/var/lib/postgresql/data"
 
@@ -65,42 +154,7 @@ in
 
           # PG init script to parse json specified in POSTGRES_MULTIPLE_DATABASES
           # creates databases, users and installs extensions for each database.
-          "${pkgs.writeScript "init.sh" ''
-            #!/bin/bash
-            function create_user_and_database() {
-              local database=$1
-              local user=$2
-              local extensions=$3
-              echo "### admin user: $POSTGRES_USER ###"
-              echo "  Creating database '$database'"
-              echo "  Creating user  '$user'"
-              psql -v --username "$POSTGRES_USER" -d "$POSTGRES_DB" <<-EOSQL
-                  CREATE USER $user;
-                  CREATE DATABASE $database;
-                  GRANT ALL PRIVILEGES ON DATABASE $database TO $user;
-            EOSQL
-            
-            # Loop through extensions and create them
-            for ext in $(echo "$extensions" | tr ',' ' '); do
-              echo "     - Installing extention $ext"
-              psql -v --username "$POSTGRES_USER" -d "$database" -c "CREATE EXTENSION $ext;"
-            done
-            }
-            
-            if [ -n "$POSTGRES_MULTIPLE_DATABASES" ]; then
-            
-              # Parse the JSON string
-              database_names=$(echo "$POSTGRES_MULTIPLE_DATABASES" | jq -r '.[0] | keys[]')
-              echo "Multiple database creation requested: $(echo "$database_names" | tr "\n" " ")"
-              
-              # Loop through each database and create it
-              for db_name in $database_names; do
-                user=$(echo "$POSTGRES_MULTIPLE_DATABASES" | jq -r ".[0] | .''${db_name} | .user")
-                extensions=$(echo "$POSTGRES_MULTIPLE_DATABASES" | jq -r ".[0] | .''${db_name} | .extensions | join(\",\")")
-                create_user_and_database "$db_name" "$user" "$extensions"
-              done
-            fi
-           ''}:/docker-entrypoint-initdb.d/init.sh"
+          "${initScript}:/always-initdb.d/init.sh"
         ];
       };
     };