Made ffmpeg streamer into its own module. Haven't tested these changes, lets...

Made ffmpeg streamer into its own module. Haven't tested these changes, lets hope they are not too broken.

coffeecam.nix → configuration.nix

 { config, pkgs, lib, ... }:
 {
-  nix.maxJobs = lib.mkDefault 2;
+  imports = [
+    "./services/coffeecam.nix"
+  ];
+
+  nix = {
+    useSandbox = true;
+    buildCores = 0;
+  }
 
   fileSystems."/" = {
     device = "/dev/disk/by-label/nixos";
@@ -36,8 +43,6 @@
 
   environment.systemPackages = with pkgs; [
     git
-    ffmpeg
-    dejavu_fonts
   ];
 
   programs.bash.enableCompletion = true;
@@ -58,34 +63,10 @@
     "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIAe0DzM/LknI0iCLYukQNOr4auToVmePbIHYkHm8BupC"
   ];
 
-  systemd.user.services.coffeecam = {
-    description = "CoffeeCam transmission";
-    serviceConfig = {
-      ExecStart = lib.replaceStrings ["\n"] [" "] ''
-        ${pkgs.ffmpeg}/bin/ffmpeg
-        -y
-        -r 15
-        -s 640x480
-        -f video4linux2
-        -i /dev/v4l/by-id/usb-Generic_USB2.0_PC_CAMERA-video-index0
-        -pix_fmt yuv420p
-        -vcodec mpeg4
-        -r 15
-        -f rtp_mpegts
-        -vf 'hflip,rotate=PI/2/180*70,drawtext=fontsize=15:fontfile=/usr/share/fonts/truetype/ttf-dejavu/DejaVuSans-Bold.ttf:rate=1/2:text=%{localtime}:fontsize=11:fontcolor='white':boxcolor=0x00000099:box=1:x=320-text_w/2:y=480-text_h'
-        -threads 2
-        -r 15 rtp://130.232.103.36:2222
-        -r 15
-        -f image2
-        -r 1/5
-        -qscale:v 4
-        -updatefirst 1
-        -vf "hflip,rotate=PI/2/180*70"
-        /dev/shm/img.jpg
-      '';
-      Restart = "on-failure";
-    };
-    wantedBy = [ "default.target" ];
+  services.coffeecam = {
+    enable = true;
+    targetAddress = "rtp://130.232.103.36:2222";
+    device = "/dev/v4l/by-id/usb-Generic_USB2.0_PC_CAMERA-video-index0";
   };
 
   system.stateVersion = "17.09";

services/coffeecam.nix

+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let cfg = config.services.coffeecam;
+
+in {
+  options.services.coffeecam = {
+    enable = mkOption {
+      description = "Enable coffeecam streaming service";
+      type = types.bool;
+      default = false;
+    };
+
+    targetAddress = mkOption {
+      description = "Stream target";
+      type = types.str;
+      example = "rtp://example.com:2222";
+    }
+
+    device = mkOption {
+      description = "Input device";
+      type = types.path;
+      default = "/dev/video0";
+    }
+
+    imagePath = mkOption {
+      description = "Output image path";
+      type = types.path;
+      default = "/dev/shm/coffeecam-static.jpg";
+    }
+
+    config = mkIf cfg.enable {
+      environment.systemPackages = [ pkgs.ffmpeg pkgs.dejavu_fonts ];
+      systemd.user.services.coffeecam = {
+        description = "CoffeeCam transmission";
+        wantedBy = [ "default.target" ];
+        after = [ "network.target" ];
+        serviceConfig = {
+          ExecStart = lib.replaceStrings ["\n"] [" "] ''
+                ${pkgs.ffmpeg}/bin/ffmpeg
+                -y
+                -r 15
+                -s 640x480
+                -f video4linux2
+                -i ${cfg.device}
+                -pix_fmt yuv420p
+                -vcodec mpeg4
+                -r 15
+                -f rtp_mpegts
+                -vf 'hflip,drawtext=fontsize=15:fontfile=/usr/share/fonts/truetype/ttf-dejavu/DejaVuSans-Bold.ttf:rate=1/2:text=%{localtime}:fontsize=11:fontcolor='white':boxcolor=0x00000099:box=1:x=320-text_w/2:y=480-text_h'
+                -threads 2
+                -r 15 ${cfg.targetAddress}
+                -r 15
+                -f image2
+                -r 1/5
+                -qscale:v 4
+                -updatefirst 1
+                ${cfg.imagePath}
+              '';
+          Restart = "on-failure";
+        };
+      };
+    };
+  }
+}