feat(pg): add postgresql devenv

README.md

@@ -54,6 +54,7 @@ In this section is require nix installed in your system, here steps to install:
 | [node14](./node14)                    | `nodejs@v14`, `yarn@1.22`, `pnpm@5`                 |
 | [go](./go)                            | `go@v1.19`, `gotools`, `golangci-lint`              |
 | [react-native](./react-native)        | [See Details](./react-native/flake.nix#L192-L212)   |
+| [pg](./pg)                            | `postgresql 14`                                     |
 
 * using as development environment: `nix develop "github:efishery/dvt?dir=<NAME>"`
 

pg/flake.nix

@@ -0,0 +1,58 @@
+{
+  description = "A Nix-flake-based PostgreSQL development environment";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, utils }:
+    {
+      overlay = final: prev:
+        let pgutil = prev.callPackage ./pgutil.nix { }; in
+        {
+          inherit (pgutil) init_pg create_pg_db start_pg stop_pg;
+        };
+
+    } // utils.lib.eachDefaultSystem (system:
+      let
+        postgresqlVersion = 14;
+        overlays = [
+          (final: prev: {
+            postgresql = prev."postgresql_${toString postgresqlVersion}";
+          })
+
+          self.overlay
+        ];
+        pkgs = import nixpkgs { inherit overlays system; };
+      in
+      {
+        devShells.default = pkgs.mkShell {
+          buildInputs = with pkgs; [
+            # postgresql 14 (specified by overlay)
+            postgresql
+
+            init_pg
+            create_pg_db
+            start_pg
+            stop_pg
+          ];
+
+          # UNCOMMENT & FILL the value of this env variable if you used this flake template in your project.
+          # PGUSER = "";
+          # PGPASSWORD = "";
+          # PGHOST = "";
+          # PGPORT = "";
+
+          shellHook = ''
+            psql --version
+          '';
+        };
+
+        packages = {
+          inherit (pkgs) init_pg create_pg_db start_pg stop_pg;
+        };
+
+      });
+}
+

pg/pgutil.nix

@@ -0,0 +1,78 @@
+# Special Thanks to: 
+# * @Rizary       - https://github.com/Rizary
+# * nix-community - https://github.com/nix-community/todomvc-nix/blob/master/nix/database/pgutil.nix
+
+{ writeScriptBin, stdenv }:
+# Change .pgdata location to $HOME/.pgdata to anticipate permission error
+{
+  init_pg = writeScriptBin "init-pg"
+    ''
+      #!${stdenv.shell}
+      pg_pid=""
+      set -euo pipefail
+      # TODO: explain what's happening here
+      LOCAL_PGHOST=$PGHOST
+      LOCAL_PGPORT=$PGPORT
+      LOCAL_PGUSER=$PGUSER
+      LOCAL_PGPASSWORD=$PGPASSWORD
+
+      initdb -D $HOME/.pgdata
+      echo "unix_socket_directories = '$(mktemp -d)'" >> $HOME/.pgdata/postgresql.conf
+
+      start-pg
+      create-pg-db default
+      unset PGUSER PGPASSWORD
+
+      psql postgres -w -c "CREATE ROLE $LOCAL_PGUSER WITH LOGIN PASSWORD '$LOCAL_PGPASSWORD'"
+
+    '';
+
+  create_pg_db = writeScriptBin "create-pg-db"
+    ''
+      #!${stdenv.shell}
+      if [ -z "$1" ]; then
+        echo "Error: create-pg-db <DATABASE NAME>. Please provide the required argument."
+        exit 1
+      fi
+
+      pg_pid=""
+      set -euo pipefail
+      LOCAL_PGDATABASE=$1
+      LOCAL_PGHOST=$PGHOST
+      LOCAL_PGPORT=$PGPORT
+      LOCAL_PGUSER=$PGUSER
+      LOCAL_PGPASSWORD=$PGPASSWORD
+      unset PGUSER PGPASSWORD
+
+      psql postgres -w -c "CREATE DATABASE $LOCAL_PGDATABASE"
+      psql postgres -w -c "GRANT ALL PRIVILEGES ON DATABASE $LOCAL_PGDATABASE TO $LOCAL_PGUSER"
+    '';
+
+  start_pg = writeScriptBin "start-pg"
+    ''
+      #!${stdenv.shell}
+      pg_pid=""
+      set -euo pipefail
+      LOCAL_PGHOST=$PGHOST
+      LOCAL_PGPORT=$PGPORT
+      LOCAL_PGUSER=$PGUSER
+      LOCAL_PGPASSWORD=$PGPASSWORD
+      unset PGUSER PGPASSWORD
+      # TODO: port
+      pg_ctl -D "$HOME/.pgdata" -w start || (echo pg_ctl failed; exit 1)
+
+      until psql postgres -c "SELECT 1" > /dev/null 2>&1 ; do
+          echo waiting for pg
+          sleep 0.5
+      done
+    '';
+
+  stop_pg = writeScriptBin "stop-pg"
+    ''
+      #!${stdenv.shell}
+      pg_pid=""
+      set -euo pipefail
+
+      pg_ctl -D $HOME/.pgdata -w -m immediate stop
+    '';
+}

templates.nix

@@ -19,4 +19,9 @@
     description = "React Native development environment";
   };
 
+  pg = {
+    path = ./pg;
+    description = "PostgreSQL development environment";
+  };
+
 }