feat(open-webui): init

ported from:
https://github.com/shivaraj-bh/ollama-flake/blob/main/services/open-webui.nix

This was also recently upstreamed to nixpkgs:
NixOS/nixpkgs#316248

nix/default.nix

@@ -10,6 +10,7 @@ in
     ./mysql
     ./nginx
     ./postgres
+    ./open-webui.nix
     ./redis-cluster.nix
     ./redis.nix
     ./zookeeper.nix

nix/open-webui.nix

@@ -0,0 +1,95 @@
+# Based on: https://github.com/NixOS/nixpkgs/blob/master/nixos/modules/services/misc/open-webui.nix
+{ pkgs, lib, name, config, ... }:
+let
+  inherit (lib) types;
+in
+{
+  options = {
+    enable = lib.mkEnableOption "Open-WebUI server";
+    package = lib.mkPackageOption pkgs "open-webui" { };
+
+    dataDir = lib.mkOption {
+      type = types.str;
+      default = "./data/${name}";
+      description = "The Open-WebUI data directory";
+    };
+
+    host = lib.mkOption {
+      type = types.str;
+      default = "127.0.0.1";
+      example = "0.0.0.0";
+      description = ''
+        The host address which the Open-WebUI server HTTP interface listens to.
+      '';
+    };
+
+    port = lib.mkOption {
+      type = types.port;
+      default = 1111;
+      example = 11111;
+      description = ''
+        Which port the Open-WebUI server listens to.
+      '';
+    };
+
+    environment = lib.mkOption {
+      type = types.attrsOf types.str;
+      default = {
+        SCARF_NO_ANALYTICS = "True";
+        DO_NOT_TRACK = "True";
+        ANONYMIZED_TELEMETRY = "False";
+      };
+      example = ''
+        {
+          OLLAMA_API_BASE_URL = "http://127.0.0.1:11434";
+          # Disable authentication
+          WEBUI_AUTH = "False";
+        }
+      '';
+      description = "Extra environment variables for Open-WebUI";
+    };
+
+    outputs.settings = lib.mkOption {
+      type = types.deferredModule;
+      internal = true;
+      readOnly = true;
+      default = {
+        processes = {
+          "${name}" = {
+            inherit (config) environment;
+            command = pkgs.writeShellApplication {
+              name = "open-webui-wrapper";
+              runtimeInputs = [ pkgs.open-webui ];
+              text = ''
+                set -x
+                if [ ! -d ${config.dataDir} ]; then
+                  mkdir -p ${config.dataDir} 
+                fi
+
+                DATA_DIR=$(readlink -f ${config.dataDir})
+                STATIC_DIR=$DATA_DIR
+                HF_HOME=$DATA_DIR
+                SENTENCE_TRANSFORMERS_HOME=$DATA_DIR
+
+                export DATA_DIR STATIC_DIR HF_HOME SENTENCE_TRANSFORMERS_HOME
+
+                open-webui serve --host ${config.host} --port ${builtins.toString config.port}
+              '';
+            };
+            readiness_probe = {
+              http_get = {
+                host = config.host;
+                port = config.port;
+              };
+              initial_delay_seconds = 2;
+              period_seconds = 10;
+              timeout_seconds = 4;
+              success_threshold = 1;
+              failure_threshold = 5;
+            };
+          };
+        };
+      };
+    };
+  };
+}

nix/open-webui_test.nix

@@ -0,0 +1,21 @@
+{ pkgs, ... }: {
+  services.open-webui."open-webui1" = {
+    enable = true;
+    environment = {
+      # Requires network connection
+      RAG_EMBEDDING_MODEL = "";
+    };
+  };
+
+  settings.processes.test = {
+    command = pkgs.writeShellApplication {
+      runtimeInputs = [ pkgs.curl ];
+      text = ''
+        # Avoid printing the entire HTML page on the stdout, we just want to know if the page is active.
+        curl http://127.0.0.1:1111 > /dev/null
+      '';
+      name = "open-webui-test";
+    };
+    depends_on."open-webui1".condition = "process_healthy";
+  };
+}

test/flake.nix

@@ -38,6 +38,7 @@
             "${inputs.services-flake}/nix/elasticsearch_test.nix"
             "${inputs.services-flake}/nix/mysql/mysql_test.nix"
             "${inputs.services-flake}/nix/nginx/nginx_test.nix"
+            "${inputs.services-flake}/nix/open-webui_test.nix"
             "${inputs.services-flake}/nix/postgres/postgres_test.nix"
             "${inputs.services-flake}/nix/redis_test.nix"
             "${inputs.services-flake}/nix/redis-cluster_test.nix"