add README.md

.editorconfig

@@ -1,5 +1,3 @@
-root = true
-
 [*]
 end_of_line = lf
 insert_final_newline = true

README.md

@@ -0,0 +1,119 @@
+# Dynix — WIP modular dynamicism for NixOS systems
+
+Dynix is a prototype for modifying an append-only NixOS configuration, and dynamically
+
+## Running the tests
+
+There are currently 3 implemented dynamicism modules: `gotosocial`, `harmonia`, and `distccd`.
+Each test uses the [NixOS test infrastructure](https://nixos.org/manual/nixos/unstable/#sec-nixos-tests) to:
+
+1. Setup a virtual machine running NixOS
+2. Configure the VM's NixOS to run a given service, with certain settings
+3. Verify that the running service is using those settings
+4. Use Dynix to change a setting for that service
+5. Verify that the running service is now using the new setting
+
+The tests themselves can be run with Nix.
+To run the test for, e.g., Gotosocial, you can run:
+
+```bash
+$ nix --experimental-features "nix-command flakes pipe-operator pipe-operators" build .#default.tests.gotosocial
+```
+
+The experimental [piping operator](https://github.com/NixOS/rfcs/pull/148) is currently used in Dynix, so you must enable the experimental feature `pipe-operator` for Lix or `pipe-operators` for CppNix (you can add both to cover both Nix implementations); flakes are used for locked inputs.
+
+
+To run a test with fewer experimental features, and without locked inputs, you can use the old CLI:
+
+```bash
+$ nix-build --experimental-features "pipe-operator pipe-operators" -A tests.gotosocial
+```
+
+All the tests at once can be run with:
+
+```bash
+$ nix build --experimental-features "nix-command flakes pipe-operator pipe-operators" .#default.allTests
+```
+
+## Gotosocial
+
+This example, implemented in [./modules/dynamicism/gotosocial.nix](./modules/dynamicism/gotosocial.nix), is tested in [./tests/gotosocial](./tests/gotosocial).
+The test sets up a VM using NixOS's `services.gotosocial` module with the following *static* [configuration](./tests/gotosocial/configuration.nix):
+
+```nix
+{
+  services.gotosocial = {
+    enable = true;
+    setupPostgresqlDB = true;
+    settings = {
+      application-name = "gotosocial-for-machine";
+      host = "gotosocial-machine.local";
+    };
+  };
+}
+```
+
+The automated [test script](./tests/gotosocial/test-script.py):
+
+1. Asserts that that the above *static* configuration is in effect (by extracting the configuration from the running Gotosocial process)
+2. Runs `dynix append "services.gotosocial.settings.application-name" "yay!"`, which modifies the append-only configuration file `/etc/nixos/dynamic.nix` in the VM filesystem
+3. Runs the dynamic activation script built by `(import <nixpkgs/nixos>).config.dynamicism.applyDynamicConfiguration { }`, which *applies* the dynamic configuration
+4. Asserts that the dynamically configured `application-name` is in effect
+5. Runs `nixos-rebuild switch` to re-apply the *static* configuration
+6. Asserts that the dynamic configuration is *no longer* in effect, and we are back to the static configuration
+
+## Harmonia
+
+This example, implemented in [./modules/dynamicism/harmonia.nix](./modules/dynamicism/harmonia.nix), is tested in [./tests/harmonia](./tests/harmonia).
+The test sets up a VM using NixOS's `services.harmonia` module with the following *static* [configuration](./tests/harmonia/configuration.nix)
+
+```nix
+{
+  services.harmonia = {
+    enable = true;
+    settings = {
+      workers = 4;
+      max_connection_rate = 256;
+    };
+  };
+}
+```
+
+The VM [test script](./tests/harmonia/test-script.py):
+
+1. Asserts that the above *static* configuration is in effect (by extracting the configuration from the running Harmonia process)
+2. Runs `dynix append "services.harmonia.settings.workers" 20`, to modify the append-only configuration file `/etc/nixos/dynamic.nix` in the VM filesystem
+3. Runs the dynamic activation script built by `(import <nixpkgs/nixos>).config.dynamicism.applyDynamicConfiguration { }`, to *apply* the dynamic configuration
+4. Asserts that the dynamically configured `workers` is in effect
+5. Runs `dynix append "services.harmonia.settings.max_connection_rate" 100`
+6. Runs the dynamic activation script
+7. Asserts that *both* `max_connection_rate` and `workers` dynamic values are in effect
+8. Runs `nixos-rebuild switch` to re-apply the *static* configuration
+9. Asserts that the dynamic configuration is *no longer* in effect, and we are back to the static configuration
+
+## Distccd
+
+This example, implemented in [./modules/dynamicism/distccd.nix](./modules/dynamicism/distccd.nix), is tested in [./tests/distccd](./tests/distccd).
+The test sets up a VM using NixOS's `services.distccd` module with the following *static* [configuration](./tests/distccd/configuration.nix):
+
+```nix
+{
+  services.distccd = {
+    jobTimeout = 900;
+    maxJobs = 12;
+    logLevel = "warning";
+  };
+}
+```
+
+The VM [test script](./tests/distccd/test-script.py):
+
+1. Asserts that the above *static* configuration is in effect (by extracting the configuration from the running Distccd process)
+2. Runs `dynix append "services.distccd.maxJobs" 4`, to modify the append-only configuration file `/etc/nixos/dynamic.nix` in the VM filesystem
+3. Runs the dynamic activation script built by `(import <nixpkgs/nixos>).config.dynamicism.applyDynamicConfiguration { }`, to *apply* the dynamic configuration
+4. Asserts that the dynamically configured `maxJobs` is in effect
+5. Runs `dynix append "services.distccd.logLevel" "error"`
+6. Runs the dynamic activation script
+7. Asserts that *both* `maxJobs` and `logLevel` dynamic values are in effect
+8. Runs `nixos-rebuild switch` to re-apply the *static* configuration
+9. Asserts that the dynamic configuration is *no longer* in effect, and we are back to the static configuration.

default.nix

@@ -1,14 +1,14 @@
 {
   pkgs ? import <nixpkgs> { },
   qpkgs ? let
-		src = fetchTree (builtins.parseFlakeRef "github:Qyriad/nur-packages");
+    src = fetchTarball "https://github.com/Qyriad/nur-packages/archive/main.tar.gz";
   in import src { inherit pkgs; },
 }: let
   inherit (qpkgs) lib;
   dynix = qpkgs.callPackage ./package.nix { }
   |> qpkgs.stdlib.mkStdenvPretty;
   byStdenv = lib.mapAttrs (stdenvName: stdenv: let
-		withStdenv = dynix.override { inherit stdenv; };
+    withStdenv = dynix.override { clangStdenv = stdenv; };
     dynix' = withStdenv.overrideAttrs (prev: {
       pname = "${prev.pname}-${stdenvName}";
     });

flake.nix

@@ -47,5 +47,9 @@
     devShells = extraDevShells // {
       default = devShell;
     };
+
+    checks = self.packages.${system}.default.tests // {
+      default = self.packages.${system}.default.allTests;
+    };
   });
 }

modules/dynamicism/dynamicism.nix

@@ -11,7 +11,6 @@ let
 
   inherit (import ./lib.nix { inherit lib; })
     typeCheck
-    convenientAttrPath
     executablePathInStore
     concatFoldl
     recUpdateFoldl

package.nix

@@ -33,7 +33,7 @@ in {
     inherit (self) dynixCommand dynixModules;
   };
 
-	installPhase = lib.dedent ''
+  installPhase = ''
     runHook preInstall
 
     mkdir -p "$out"

tests/default.nix

@@ -1,7 +1,7 @@
 {
   pkgs ? import <nixpkgs> { },
   qpkgs ? let
-    src = fetchTree (builtins.parseFlakeRef "github:Qyriad/nur-packages");
+    src = fetchTarball "https://github.com/Qyriad/nur-packages/archive/main.tar.gz";
   in import src { inherit pkgs; },
   callPackage ? qpkgs.callPackage,
   lib ? qpkgs.lib,

tests/distccd/configuration.nix

@@ -1,9 +1,11 @@
 { ... }:
+
 {
   services.distccd = {
     enable = true;
     jobTimeout = 900;
     maxJobs = 12;
+    logLevel = "warning";
     nice = -10;
   };
 

tests/distccd/test-script.py

@@ -1,7 +1,5 @@
 import argparse
 import functools
-#from pathlib import Path
-#from pprint import pformat
 import shlex
 import textwrap
 from typing import Any, cast, TYPE_CHECKING
@@ -64,7 +62,6 @@ def get_cli_args() -> argparse.Namespace:
     machine.log(f"{cmdline_args=}")
     print(f"{cmdline_args=}")
 
-    #return shlex.join(cmdline_args[1:])
     args, rest = parser.parse_known_args(cmdline_args)
     return args
 
@@ -77,12 +74,7 @@ def dynix_append(option: str, value: Any):
 @beartype
 def do_apply():
     expr = textwrap.dedent("""
-        let
+        (import <nixpkgs/nixos> { }).config.dynamicism.applyDynamicConfiguration { }
-            nixos = import <nixpkgs/nixos> { };
-        in nixos.config.dynamicism.applyDynamicConfiguration {
-            baseConfiguration = /etc/nixos/configuration.nix;
-            newConfiguration = /etc/nixos/dynamic.nix;
-        }
     """).strip()
 
     machine.succeed(rf"""
@@ -90,12 +82,13 @@ def do_apply():
     """.strip())
 
 machine.wait_for_unit("default.target")
-assert "lix" in machine.succeed("nix --version").lower()
+machine.wait_for_unit("install-dynix.service")
-machine.log("INIT")
+
+dynix_out = machine.succeed("dynix --version")
+assert "dynix" in dynix_out, f"dynix not in {dynix_out=}"
 
 # Config should have our initial values.
 args = get_cli_args()
-#assert '--jobs 12' in args, f'--jobs 12 not in {args=}'
 assert args.jobs == 12, f'{args.jobs=} != 12'
 assert args.job_lifetime == 900, f'{args.job_lifetime} != 900'
 assert args.log_level == 'warning', f'{args.log_level=} != warning'
@@ -105,17 +98,16 @@ with machine.nested("must succeed: initial nixos-rebuild switch"):
 
 # Config should not have changed.
 args = get_cli_args()
-#machine.log(f"config.toml after first rebuild: {indent(pformat(args))}")
+assert args.jobs == 12, f'{args.jobs=} != 12'
-#assert int(args['workers']) == 4, f"{args['workers']=} != 4"
+assert args.job_lifetime == 900, f'{args.job_lifetime} != 900'
-#assert int(args['max_connection_rate']) == 256, f"{args['max_connection_rate']=} != 256"
+assert args.log_level == 'warning', f'{args.log_level=} != warning'
-#
+
 new_jobs = 4
 dynix_append("services.distccd.maxJobs", new_jobs)
 do_apply()
 
-args = get_cli_args()
-
 # Only jobs should have changed. The others should still be default.
+args = get_cli_args()
 assert args.jobs == new_jobs, f'{args.jobs=} != {new_jobs=}'
 assert args.job_lifetime == 900, f'{args.job_lifetime} != 900'
 assert args.log_level == 'warning', f'{args.log_level=} != warning'
@@ -125,6 +117,13 @@ dynix_append("services.distccd.logLevel", f'"{new_log_level}"')
 do_apply()
 
 args = get_cli_args()
-#assert args.jobs == new_jobs, f'{args.jobs=} != {new_jobs=}'
+assert args.jobs == new_jobs, f'{args.jobs=} != {new_jobs=}'
-#assert args.job_lifetime == 900, f'{args.job_lifetime} != 900'
+assert args.job_lifetime == 900, f'{args.job_lifetime} != 900'
 assert args.log_level == new_log_level, f'{args.log_level=} != {new_log_level=}'
+
+# And this should set everything back.
+machine.succeed("env PAGER= nixos-rebuild switch --log-format raw-with-logs --fallback")
+args = get_cli_args()
+assert args.jobs == 12, f'{args.jobs=} != 12'
+assert args.job_lifetime == 900, f'{args.job_lifetime} != 900'
+assert args.log_level == 'warning', f'{args.log_level=} != warning'

tests/gotosocial/configuration-package.nix

@@ -1,7 +0,0 @@
-{
-  runCommand,
-}: runCommand "tests-gotosocial-configuration-dot-nix" {
-} ''
-  set -euo pipefail
-  install -Dm a=r ${./configuration.nix} "$out/share/nixos/configuration.nix"
-''

tests/gotosocial/default.nix

@@ -1,7 +0,0 @@
-/**
- * Convenience shortcut for running this test from the command-line.
- * Normally this test is initialized from /tests/default.nix.
- */
-{
-  pkgs ? import <nixpkgs> { },
-}: pkgs.testers.runNixOSTest ./test.nix

tests/gotosocial/hardware-configuration.nix

@@ -1,7 +0,0 @@
-/** Dummy hardware configuration.
- * Will be replaced with the real one in the test VM.
- */
-{ ... }:
-{
-
-}

tests/gotosocial/test-script.py

@@ -61,12 +61,7 @@ def dynix_append(option: str, value: str):
 @beartype
 def do_apply():
     expr = textwrap.dedent("""
-        let
+        (import <nixpkgs/nixos> { }).config.dynamicism.applyDynamicConfiguration { }
-            nixos = import <nixpkgs/nixos> { };
-        in nixos.config.dynamicism.applyDynamicConfiguration {
-            baseConfiguration = /etc/nixos/configuration.nix;
-            newConfiguration = /etc/nixos/dynamic.nix;
-        }
     """).strip()
 
     machine.succeed(rf"""
@@ -75,7 +70,6 @@ def do_apply():
 
 
 machine.wait_for_unit("default.target")
-assert "lix" in machine.succeed("nix --version").lower()
 machine.wait_for_unit("install-dynix.service")
 
 dynix_out = machine.succeed("dynix --version")
@@ -94,6 +88,12 @@ except StopIteration:
     raise AssertionError(f"no 'application-name:' found in config file: {textwrap.indent(config_text, "  ")}")
 assert "gotosocial-for-machine" in application_name, f"'gotosocial-for-machine' should be in {application_name=}"
 
+try:
+    host = next(line for line in lines if line.startswith("host:"))
+except StopIteration:
+    raise AssertionError(f"no 'host:' found in config file: {textwrap.indent(config_text, "  ")}")
+assert "gotosocial-machine" in host, f"'gotosocial-machine' should be in {host=}"
+
 new_app_name = "yay!"
 dynix_append("services.gotosocial.settings.application-name", f'"{new_app_name}"')
 do_apply()

tests/harmonia/configuration.nix

@@ -1,20 +1,6 @@
-{ lib, modulesPath, ... }:
+{ ... }:
-let
-  moduleList = import "${modulesPath}/module-list.nix";
 
-  dynixFromSearchPath = let
-    res = builtins.tryEval <dynix>;
-  in lib.optional res.success res.value;
-in
 {
-  imports = [
-    #"${modulesPath}/testing/test-instrumentation.nix"
-    #./hardware-configuration.nix
-  ] ++ lib.concatLists [
-    #dynixFromSearchPath
-    moduleList
-  ];
-
   dynamicism.for.harmonia.enable = true;
   services.harmonia = {
     enable = true;

tests/harmonia/hardware-configuration.nix

@@ -1,4 +0,0 @@
-{ ... }:
-{
-
-}

tests/harmonia/test-script.py

@@ -1,6 +1,5 @@
 import functools
 from pathlib import Path
-from pprint import pformat
 import shlex
 import textwrap
 import tomllib
@@ -64,12 +63,7 @@ def dynix_append(option: str, value: Any):
 @beartype
 def do_apply():
     expr = textwrap.dedent("""
-        let
+        (import <nixpkgs/nixos> { }).config.dynamicism.applyDynamicConfiguration { }
-            nixos = import <nixpkgs/nixos> { };
-        in nixos.config.dynamicism.applyDynamicConfiguration {
-            baseConfiguration = /etc/nixos/configuration.nix;
-            newConfiguration = /etc/nixos/dynamic.nix;
-        }
     """).strip()
 
     machine.succeed(rf"""
@@ -77,12 +71,13 @@ def do_apply():
     """.strip())
 
 machine.wait_for_unit("default.target")
-assert "lix" in machine.succeed("nix --version").lower()
+machine.wait_for_unit("install-dynix.service")
-machine.log("INIT")
+
+dynix_out = machine.succeed("dynix --version")
+assert "dynix" in dynix_out, f"dynix not in {dynix_out=}"
 
 # Config should have our initial values.
 config_toml = get_config_file()
-machine.log(f"config.toml BEFORE first rebuild (initial): {indent(pformat(config_toml))}")
 assert int(config_toml['workers']) == 4, f"{config_toml['workers']=} != 4"
 assert int(config_toml['max_connection_rate']) == 256, f"{config_toml['max_connection_rate']=} != 256"
 
@@ -91,7 +86,6 @@ with machine.nested("must succeed: initial nixos-rebuild switch"):
 
 # Config should not have changed.
 config_toml = get_config_file()
-machine.log(f"config.toml after first rebuild: {indent(pformat(config_toml))}")
 assert int(config_toml['workers']) == 4, f"{config_toml['workers']=} != 4"
 assert int(config_toml['max_connection_rate']) == 256, f"{config_toml['max_connection_rate']=} != 256"
 
@@ -101,7 +95,6 @@ do_apply()
 
 # Workers, but not max connection rate, should have changed.
 config_toml = get_config_file()
-machine.log(f"config.toml after DYNAMIC ACTIVATION: {indent(pformat(config_toml))}")
 assert int(config_toml['workers']) == new_workers, f"{config_toml['workers']=} != {new_workers}"
 assert int(config_toml['max_connection_rate']) == 256, f"{config_toml['max_connection_rate']=} != 256"
 
@@ -109,16 +102,14 @@ new_max_connection_rate = 100
 dynix_append("services.harmonia.settings.max_connection_rate", new_max_connection_rate)
 do_apply()
 
-# Max connection rate should have changed, but workers should have reverted.
+# Max connection rate should have changed, and workers should be the same as before.
 config_toml = get_config_file()
-machine.log(f"config_toml after SECOND dynamic activation: {indent(pformat(config_toml))}")
 assert int(config_toml['max_connection_rate']) == new_max_connection_rate, f"{config_toml['max_connection_rate']=} != {new_max_connection_rate}"
+assert int(config_toml['workers']) == new_workers, f"{config_toml['workers']=} != {new_workers}"
 
 # And this should set everything back.
 machine.succeed("env PAGER= nixos-rebuild switch --log-format raw-with-logs --fallback")
-machine.systemctl("restart harmonia.service")
 machine.wait_for_unit("harmonia.service")
 config_toml = get_config_file()
-machine.log(f"config_toml after NORMAL activation: {indent(pformat(config_toml))}")
 assert int(config_toml['max_connection_rate']) == 256, f'{config_toml["max_connection_rate"]=} != 256'
 assert int(config_toml['workers']) == 4, f'{config_toml["workers"]=} != 4'

tests/tzupdate/configuration.nix

@@ -1,67 +0,0 @@
-{ pkgs, lib, config, modulesPath, ... }:
-let
-  name = config.networking.hostName;
-  moduleList = import "${modulesPath}/module-list.nix";
-
-  dynixFromSearchPath = let
-    res = builtins.tryEval <dynix>;
-  in lib.optional res.success res.value;
-in
-{
-  imports = [
-    "${modulesPath}/testing/test-instrumentation.nix"
-    ./hardware-configuration.nix
-  ] ++ lib.concatLists [
-    moduleList
-    dynixFromSearchPath
-  ];
-
-  dynamicism.for.tzupdate.enable = true;
-  services.tzupdate = {
-    enable = true;
-  };
-
-  system.switch.enable = true;
-  documentation.enable = false;
-
-  networking.hostName = "tzupdate-machine";
-
-  boot.loader.grub = {
-    enable = true;
-    device = "/dev/vda";
-    forceInstall = true;
-  };
-
-  nix = {
-    package = pkgs.lixPackageSets.latest.lix;
-    nixPath = [
-      "nixpkgs=${pkgs.path}"
-      "/nix/var/nix/profiles/per-user/root/profile/share/nixos/modules"
-    ];
-
-    settings = {
-      experimental-features = [ "nix-command" "pipe-operator" ];
-      substituters = lib.mkForce [ ];
-      hashed-mirrors = null;
-      connect-timeout = 1;
-      # For my debugging purposes.
-      show-trace = true;
-    };
-  };
-
-  environment.pathsToLink = [ "/share" ];
-  environment.extraOutputsToInstall = [ "modules" ];
-  environment.variables = {
-    "NIXOS_CONFIG" = "/etc/nixos/configuration.nix";
-  };
-
-  environment.shellAliases = {
-    ls = "eza --long --header --group --group-directories-first --classify --binary";
-  };
-
-  environment.systemPackages = with pkgs; [
-    eza
-    fd
-    ripgrep
-  ];
-}

tests/tzupdate/hardware-configuration.nix

@@ -1,4 +0,0 @@
-{ ... }:
-{
-
-}

tests/tzupdate/test-script.py

@@ -1,52 +0,0 @@
-#from pathlib import Path
-#import shlex
-#import textwrap
-from typing import cast, TYPE_CHECKING
-
-from beartype import beartype
-
-from test_driver.machine import Machine
-from test_driver.errors import RequestedAssertionFailed
-
-if TYPE_CHECKING:
-    global machine
-    machine = cast(Machine, ...)
-    assert machine.shell is not None
-
-ls = "eza -lah --color=always --group-directories-first"
-
-@beartype
-def run_log(machine: Machine, *commands: str, timeout: int | None = 60) -> str:
-    output = ""
-    for command in commands:
-        with machine.nested(f"must succeed: {command}"):
-            (status, out) = machine.execute(f"{command} | tee /dev/stderr", timeout=timeout)
-            if status != 0:
-                machine.log(f"output: {out}")
-                raise RequestedAssertionFailed(
-                    f"command `{command}` failed (exit code {status})",
-                )
-            output += out
-
-    return output
-
-machine.wait_for_unit("default.target")
-assert "lix" in machine.succeed("nix --version").lower()
-machine.log("INIT")
-
-
-machine.succeed("nixos-generate-config")
-machine.succeed("mkdir -vp /etc/nixos")
-# Dereference is required since that configuration.nix is probably a symlink to the store.
-machine.succeed("cp -rv --dereference /run/current-system/sw/share/nixos/configuration.nix /etc/nixos/")
-
-machine.succeed("env PAGER= nixos-rebuild switch --log-format raw-with-logs --fallback")
-
-@beartype
-def get_interval() -> str:
-    prop = machine.get_unit_property("tzupdate.timer", "OnCalendar")
-    print(f"{prop=}")
-
-    return prop
-
-get_interval()

tests/tzupdate/test.nix

@@ -1,24 +0,0 @@
-{ ... }:
-
-{
-  name = "nixos-test-dynamicism-tzupdate";
-
-  extraPythonPackages = p: [
-    p.beartype
-  ];
-
-  nodes.machine = { name, pkgs, ... }: {
-    imports = [ ./configuration.nix ];
-
-    environment.systemPackages = let
-      configFileTree = pkgs.runCommand "${name}-configuration-dot-nix" { } ''
-        set -euo pipefail
-        install -Dm a=r ${./configuration.nix} "$out/share/nixos/configuration.nix"
-      '';
-    in [
-      configFileTree
-    ];
-  };
-
-  testScript = builtins.readFile ./test-script.py;
-}