nix: add postgres and multiple system support

.gitignore

@@ -1 +1,2 @@
 /target/
+/.db/

docker-compose.yml

@@ -1,15 +0,0 @@
-version: "3"
-
-services:
-  database:
-    image: "postgres:latest"
-    environment:
-      POSTGRES_DB: postgres
-      POSTGRES_PASSWORD: postgres
-    ports:
-      - 5432:5432
-    volumes:
-      - db_data:/var/lib/postgresql/data/
-
-volumes:
-  db_data:

flake.lock

@@ -5,11 +5,11 @@
         "systems": "systems"
       },
       "locked": {
-        "lastModified": 1681202837,
-        "narHash": "sha256-H+Rh19JDwRtpVPAWp64F+rlEtxUWBAQW28eAi3SRSzg=",
+        "lastModified": 1694529238,
+        "narHash": "sha256-zsNZZGTGnMOf9YpHKJqMSsa0dXbfmxeoJ7xHlrt+xmY=",
         "owner": "numtide",
         "repo": "flake-utils",
-        "rev": "cfacdce06f30d2b68473a46042957675eebb3401",
+        "rev": "ff7b65b44d01cf9ba6a71320833626af21126384",
         "type": "github"
       },
       "original": {
@@ -34,39 +34,28 @@
         "type": "github"
       }
     },
-    "nixpkgs_2": {
-      "locked": {
-        "lastModified": 1681358109,
-        "narHash": "sha256-eKyxW4OohHQx9Urxi7TQlFBTDWII+F+x2hklDOQPB50=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "96ba1c52e54e74c3197f4d43026b3f3d92e83ff9",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixpkgs-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
     "root": {
       "inputs": {
+        "flake-utils": "flake-utils",
         "nixpkgs": "nixpkgs",
         "rust-overlay": "rust-overlay"
       }
     },
     "rust-overlay": {
       "inputs": {
-        "flake-utils": "flake-utils",
-        "nixpkgs": "nixpkgs_2"
+        "flake-utils": [
+          "flake-utils"
+        ],
+        "nixpkgs": [
+          "nixpkgs"
+        ]
       },
       "locked": {
-        "lastModified": 1696039808,
-        "narHash": "sha256-7TbAr9LskWG6ISPhUdyp6zHboT7FsFrME5QsWKybPTA=",
+        "lastModified": 1696126582,
+        "narHash": "sha256-uo4cn/d2rHPy/fpKZKFBOaVO531zs/Doxz43imrpqZM=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "a4c3c904ab29e04a20d3a6da6626d66030385773",
+        "rev": "fc6fe50d9a4540a1111731baaa00f207301fdeb7",
         "type": "github"
       },
       "original": {

flake.nix

@@ -3,13 +3,17 @@
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
-    rust-overlay.url = "github:oxalica/rust-overlay";
+    flake-utils.url = "github:numtide/flake-utils";
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+      inputs.flake-utils.follows = "flake-utils";
+    };
   };
 
-  outputs = { self, nixpkgs, rust-overlay }:
+  outputs = { self, nixpkgs, flake-utils, rust-overlay }:
     let
-      #supportedSystems = [ "x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
-      system = "x86_64-linux";
+      supportedSystems = [ "x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
 
       overlays = [
         (final: prev: {
@@ -20,24 +24,44 @@
 
         (import rust-overlay)
       ];
-
-      pkgs = import nixpkgs {
-        inherit system overlays;
-      };
     in
-    {
-      devShells.${system}.default = with pkgs; mkShell {
-        packages = [
-          elixir
-          elixir-ls
-          protobuf
-          protoc-gen-elixir
-          rust-bin.stable.latest.default
-        ] ++ lib.optionals stdenv.isLinux [ inotify-tools ];
+    flake-utils.lib.eachSystem supportedSystems (system:
+      let
+        pkgs = import nixpkgs { inherit system overlays; };
+      in
+      {
+        devShells.default = with pkgs; mkShell {
+          packages = [
+            elixir
+            elixir-ls
+            protobuf
+            protoc-gen-elixir
+            rust-bin.stable.latest.default
+            postgresql
+          ] ++ lib.optionals stdenv.isLinux [ inotify-tools ];
 
-        inputsFrom = [
-          protoc-gen-elixir
-        ];
-      };
-    };
+          inputsFrom = [
+            protoc-gen-elixir
+          ];
+
+          shellHook = ''
+            export PGDATA=$PWD/.db
+            export PGHOST=/tmp
+            export DB_LOG=$PWD/.db/log
+
+            if [ ! -d $PGDATA ]; then
+              initdb $PGDATA --auth=trust
+            fi
+
+            if ! pg_ctl status >/dev/null; then
+              pg_ctl start -l $DB_LOG -o "-c unix_socket_directories=$PGHOST"
+            fi
+
+            user_exists=$(psql --csv -t -d postgres -c "SELECT count(*) FROM pg_user WHERE usename='postgres'")
+            if [ $user_exists != "1" ]; then
+              createuser -s -h $PGHOST postgres
+            fi
+          '';
+        };
+      });
 }