[Devbox] Set up ssh-agent-switcher.

Signed-off-by: jmug <u.g.a.mariano@gmail.com>

flake.lock

@@ -84,6 +84,24 @@
         "type": "github"
       }
     },
+    "flake-utils_3": {
+      "inputs": {
+        "systems": "systems_2"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
     "ghostty": {
       "inputs": {
         "flake-compat": "flake-compat_2",
@@ -299,6 +317,22 @@
       }
     },
     "nixpkgs_3": {
+      "locked": {
+        "lastModified": 1749086602,
+        "narHash": "sha256-DJcgJMekoxVesl9kKjfLPix2Nbr42i7cpEHJiTnBUwU=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "4792576cb003c994bd7cc1edada3129def20b27d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "release-25.05",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_4": {
       "locked": {
         "lastModified": 1747542820,
         "narHash": "sha256-GaOZntlJ6gPPbbkTLjbd8BMWaDYafhuuYRNrxCGnPJw=",
@@ -327,6 +361,7 @@
         "nixpkgs-msft-go": "nixpkgs-msft-go",
         "nixpkgs-unstable": "nixpkgs-unstable_2",
         "sops-nix": "sops-nix",
+        "ssh-agent-switcher": "ssh-agent-switcher",
         "walker": "walker"
       }
     },
@@ -350,6 +385,26 @@
         "type": "github"
       }
     },
+    "ssh-agent-switcher": {
+      "inputs": {
+        "flake-utils": "flake-utils_3",
+        "nixpkgs": "nixpkgs_3"
+      },
+      "locked": {
+        "lastModified": 1749108251,
+        "narHash": "sha256-1tXo21//5Mmy1zfyQoRcaTM6uuK4WHAtFq6PpoCExkY=",
+        "owner": "AYM1607",
+        "repo": "ssh-agent-switcher",
+        "rev": "6cd7ce973cf08656d42e475945216d8c0f0b0c7b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "AYM1607",
+        "repo": "ssh-agent-switcher",
+        "rev": "6cd7ce973cf08656d42e475945216d8c0f0b0c7b",
+        "type": "github"
+      }
+    },
     "systems": {
       "locked": {
         "lastModified": 1681028828,
@@ -366,6 +421,21 @@
       }
     },
     "systems_2": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    },
+    "systems_3": {
       "locked": {
         "lastModified": 1689347949,
         "narHash": "sha256-12tWmuL2zgBgZkdoB6qXZsgJEH9LR3oUgpaQq2RbI80=",
@@ -382,8 +452,8 @@
     },
     "walker": {
       "inputs": {
-        "nixpkgs": "nixpkgs_3",
-        "systems": "systems_2"
+        "nixpkgs": "nixpkgs_4",
+        "systems": "systems_3"
       },
       "locked": {
         "lastModified": 1748171996,

flake.nix

@@ -38,8 +38,8 @@
 
     # ssh-agent forwarder for linux.
     ssh-agent-switcher = {
-      url = "github:AYM1607/ssh-agent-switcher/6cd7ce973cf08656d42e475945216d8c0f0b0c7b"
-    }
+      url = "github:AYM1607/ssh-agent-switcher/6cd7ce973cf08656d42e475945216d8c0f0b0c7b";
+    };
   };
 
   outputs = {
@@ -100,6 +100,7 @@
           ./hosts/devbox/configuration.nix
           home-manager.nixosModules.home-manager
           {
+            home-manager.extraSpecialArgs = { inherit inputs ssh-agent-switcher; };
             home-manager.useGlobalPkgs = true;
             home-manager.useUserPackages = true;
             home-manager.users.jmug = import ./hosts/devbox/home.nix;

hosts/devbox/home.nix

@@ -1,5 +1,4 @@
-{ inputs, config, pkgs, ... } :
-
+{ inputs, config, pkgs, ssh-agent-switcher, ... } :
 {
 
   imports = [
@@ -28,13 +27,6 @@
       exercism
       # Thin provisioning tools
       thin-provisioning-tools
-      pkgs.writeShellApplication {
-        name = "sas";
-        runtimeInputs = [ inputs.ssh-agent-switcher.aarch64-linux.default ];
-        text = ''
-          ssh-agent-switcher
-        '';
-      }
     ];
 
     stateVersion = "24.11";
@@ -52,6 +44,17 @@
       # TODO: Interpolate the name of the host here.
       nrsw = "sudo nixos-rebuild switch --flake /home/jmug/nixos#devbox";
     };
+    loginExtra = ''
+    if [ ! -e "/tmp/ssh-agent.''${USER}" ]; then
+      if [ -n "''${ZSH_VERSION}" ]; then
+          eval ${ssh-agent-switcher.packages.x86_64-linux.default}/bin/ssh-agent-switcher 2>/dev/null "&!"
+      else
+          ${ssh-agent-switcher.packages.x86_64-linux.default}/bin/ssh-agent-switcher 2>/dev/null &
+          disown 2>/dev/null || true
+      fi
+    fi
+    export SSH_AUTH_SOCK="/tmp/ssh-agent.''${USER}"
+    '';
   };
   
   services.ssh-agent.enable = true;