web01: Use pict-rs 0.4.0

This allows separation of images & database which is something we
want because we use the Hetzner Storage Box for images but local
disk for the state db.

flake.lock

@@ -40,6 +40,24 @@
         "type": "github"
       }
     },
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1687171271,
+        "narHash": "sha256-BJlq+ozK2B1sJDQXS3tzJM5a+oVZmi1q0FlBK/Xqv7M=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "abfb11bd1aec8ced1c9bb9adfe68018230f4fb3c",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
     "hercules-ci-effects": {
       "inputs": {
         "flake-parts": [
@@ -169,6 +187,28 @@
         "type": "github"
       }
     },
+    "pict-rs": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1688870061,
+        "narHash": "sha256-1WNd7Ei21g01S5ko6y+uyhHP+xlGtnrwU8MLMxnW3P8=",
+        "ref": "refs/tags/v0.4.0",
+        "rev": "fa74e3c82d942f7732087c86bc509aeb9216f487",
+        "revCount": 705,
+        "type": "git",
+        "url": "https://git.asonix.dog/asonix/pict-rs.git"
+      },
+      "original": {
+        "ref": "refs/tags/v0.4.0",
+        "type": "git",
+        "url": "https://git.asonix.dog/asonix/pict-rs.git"
+      }
+    },
     "root": {
       "inputs": {
         "disko": "disko",
@@ -179,6 +219,7 @@
         "nixpkgs-update": "nixpkgs-update",
         "nixpkgs-update-github-releases": "nixpkgs-update-github-releases",
         "nur-update": "nur-update",
+        "pict-rs": "pict-rs",
         "sops-nix": "sops-nix",
         "srvos": "srvos",
         "tf-pkgs": "tf-pkgs",
@@ -226,6 +267,21 @@
         "type": "github"
       }
     },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    },
     "tf-pkgs": {
       "locked": {
         "lastModified": 1685899275,

flake.nix

@@ -42,6 +42,13 @@
     treefmt-nix.url = "github:numtide/treefmt-nix";
     treefmt-nix.inputs.nixpkgs.follows = "nixpkgs";
 
+    # Pict-rs is the image hosting server for Lemmy.
+    # 0.4 comes with a separation of database and file storage which we require but isn't
+    # in a stable release yet.
+    # After pict-rs 0.4 is in nixpkgs we can remove this input.
+    pict-rs.url = "git+https://git.asonix.dog/asonix/pict-rs.git?ref=refs/tags/v0.4.0";
+    pict-rs.inputs.nixpkgs.follows = "nixpkgs";
+
     tf-pkgs.url = "github:NixOS/nixpkgs/3f697e808b31a955462bc0b20b229d4072c99aa7";
   };
 

hosts/web01/lemmy.nix

@@ -1,4 +1,4 @@
-_:
+{ inputs, pkgs, lib, ... }:
 
 let
   domain = "lemmy.nix-community.org";
@@ -25,6 +25,23 @@ in
     dataDir = "/mnt/lemmy-pict-rs";
   };
 
+  # In the transition from 0.3.3 to 0.4 pict-rs breaks it's previous
+  # conflation of data storage and statate storage.
+  # 0.4 is still not released but we need this separation already.
+  # This renames the env vars set by the NixOS module.
+  #
+  # Migrate to using upstream NixOS definitions when 0.4 is released.
+  systemd.services.pict-rs.environment = {
+    PICTRS__REPO__PATH = "/var/lib/pict-rs/sled";
+    PICTRS__STORE__PATH = "/mnt/lemmy-pict-rs";
+  };
+  systemd.services.pict-rs.serviceConfig.ExecStart = lib.mkForce "${lib.getExe pkgs.pict-rs} run";
+  nixpkgs.overlays = [
+    (_final: _prev: {
+      inherit (inputs.pict-rs.packages.x86_64-linux) pict-rs;
+    })
+  ];
+
   # Pict-rs uses DynamicUser
   systemd.services.pict-rs.serviceConfig.ReadWritePaths = "/mnt/lemmy-pict-rs";
 }