diff --git a/nixos/modules/virtualisation/amazon-init.nix b/nixos/modules/virtualisation/amazon-init.nix index be83607c0af7..4f2f8df90eb8 100644 --- a/nixos/modules/virtualisation/amazon-init.nix +++ b/nixos/modules/virtualisation/amazon-init.nix @@ -16,6 +16,16 @@ let userData=/etc/ec2-metadata/user-data + # Check if user-data looks like a shell script and execute it with the + # runtime shell if it does. Otherwise treat it as a nixos configuration + # expression + if IFS= LC_ALL=C read -rN2 shebang < $userData && [ "$shebang" = '#!' ]; then + # NB: we cannot chmod the $userData file, this is why we execute it via + # `pkgs.runtimeShell`. This means we have only limited support for shell + # scripts compatible with the `pkgs.runtimeShell`. + exec ${pkgs.runtimeShell} $userData + fi + if [ -s "$userData" ]; then # If the user-data looks like it could be a nix expression, # copy it over. Also, look for a magic three-hash comment and set diff --git a/nixos/tests/all-tests.nix b/nixos/tests/all-tests.nix index 4965cd9228d1..9043ab144abe 100644 --- a/nixos/tests/all-tests.nix +++ b/nixos/tests/all-tests.nix @@ -24,6 +24,7 @@ in _3proxy = handleTest ./3proxy.nix {}; acme = handleTest ./acme.nix {}; agda = handleTest ./agda.nix {}; + amazon-init-shell = handleTest ./amazon-init-shell.nix {}; ammonite = handleTest ./ammonite.nix {}; atd = handleTest ./atd.nix {}; avahi = handleTest ./avahi.nix {}; diff --git a/nixos/tests/amazon-init-shell.nix b/nixos/tests/amazon-init-shell.nix new file mode 100644 index 000000000000..f9268b2f3a00 --- /dev/null +++ b/nixos/tests/amazon-init-shell.nix @@ -0,0 +1,40 @@ +# This test verifies that the amazon-init service can treat the `user-data` ec2 +# metadata file as a shell script. If amazon-init detects that `user-data` is a +# script (based on the presence of the shebang #! line) it executes it and +# exits. +# Note that other tests verify that amazon-init can treat user-data as a nixos +# configuration expression. + +{ system ? builtins.currentSystem, + config ? {}, + pkgs ? import ../.. { inherit system config; } +}: + +with import ../lib/testing-python.nix { inherit system pkgs; }; +with pkgs.lib; + +makeTest { + name = "amazon-init"; + meta = with maintainers; { + maintainers = [ urbas ]; + }; + machine = { ... }: + { + imports = [ ../modules/profiles/headless.nix ../modules/virtualisation/amazon-init.nix ]; + services.openssh.enable = true; + networking.hostName = ""; + environment.etc."ec2-metadata/user-data" = { + text = '' + #!/usr/bin/bash + + echo successful > /tmp/evidence + ''; + }; + }; + testScript = '' + # To wait until amazon-init terminates its run + unnamed.wait_for_unit("amazon-init.service") + + unnamed.succeed("grep -q successful /tmp/evidence") + ''; +}