docs: add basic documentation to the infra-rebuild root command

This way, by only looking at the help page, users should get a good
enough idea on how to use infra-rebuild to start using it.

README.md

@@ -20,7 +20,7 @@ However to override aspects of the target host for specific or all hosts, infra-
 
 ## Configuration
 
-infra-rebuild accepts optional configuration in a `deployment_configuration.json`. \
+infra-rebuild accepts optional configuration in a `deployment_configuration.json` present in the flake repos root. \
 The following keys are available to be set for configuring various aspects of deployment for specific or all hosts:
 
 - `default.targetPort`: A default port to use for connecting to all host.

src/infra_rebuild/cli/__init__.py

@@ -3,54 +3,118 @@ import click
 from infra_rebuild import operations
 
 reboot_option_help_text = "Reboot the target hosts after running the operation."
+flake_option_help_text = "URI of the flake to use. Defaults to the current direcory."
 
 
-@click.group(context_settings={"help_option_names": ["-h", "--help"]}, invoke_without_command=True)
+def initialize_recursive_option(ctx, option_name, default_value):
+    """Helper function for initializing a recursive option.
+
+    Arguments:
+    `ctx` -- The click context passed to the calling command.
+    `option_name` -- The name of the option in question.
+    `default_value` -- A default value for the option.
+
+    Simply sets the value of the recursive option (`ctx.obj[option_name]`) to `default_value`.
+    """
+    ctx.obj[option_name] = default_value
+
+
+def update_recursive_option(ctx, option_name, given_value):
+    """Helper function for updating a recursive option.
+
+    Arguments:
+    ctx -- The click context passed to the calling command.
+    option_name -- The name of the option in question.
+    given_value -- The value the calling command received for the option.
+
+    It overrides the current value for the recursive option (`ctx.obj[option_name]`) with `given_value`, if `given_value` isn't `None`.
+    This ensure precedence of the innermost command (since the innermost command would call this function last).
+    """  # noqa: E501
+    if given_value is not None:
+        ctx.obj[option_name] = given_value
+
+
+@click.group(
+    context_settings={"help_option_names": ["-h", "--help"]},
+    invoke_without_command=True,
+    help="""Runs COMMAND for each given host.
+
+         The commands mirror the operations of nixos-rebuild (with the exception of reboot, which is simply a convenience alias for "boot --reboot").
+
+         For commands acting remotely (boot, reboot, switch, test) infra-rebuild tries to be useful without any configuration by taking the FQDN from the hosts NixOS configuration as the target host.
+         However infra-rebuild also accepts configuration to override various aspects of the target host for specific or all hosts.
+         See the documentation on configuration for more information.""",  # noqa: E501
+)
 @click.version_option(prog_name="infra-rebuild")
-def infra_rebuild():
-    pass
+@click.pass_context
+@click.option("--flake", help=flake_option_help_text)
+def infra_rebuild(ctx, flake):
+    ctx.ensure_object(dict)
+    initialize_recursive_option(ctx, "flake", ".")
+    update_recursive_option(ctx, "flake", flake)
 
 
 @infra_rebuild.command()
+@click.pass_context
+@click.option("--flake", help=flake_option_help_text)
 @click.argument("hosts", nargs=-1)
-def build(hosts):
-    operations.run("build", hosts)
+def build(ctx, flake, hosts):
+    update_recursive_option(ctx, "flake", flake)
+    operations.run("build", hosts, ctx.obj["flake"])
 
 
 @infra_rebuild.command()
+@click.pass_context
+@click.option("--flake", help=flake_option_help_text)
 @click.argument("hosts", nargs=-1)
-def build_vm(hosts):
-    operations.run("build-vm", hosts)
+def build_vm(ctx, flake, hosts):
+    update_recursive_option(ctx, "flake", flake)
+    operations.run("build-vm", hosts, ctx.obj["flake"])
 
 
 @infra_rebuild.command()
+@click.pass_context
+@click.option("--flake", help=flake_option_help_text)
 @click.argument("hosts", nargs=-1)
-def build_vm_with_bootloader(hosts):
-    operations.run("build-vm-with-bootloader", hosts)
+def build_vm_with_bootloader(ctx, flake, hosts):
+    update_recursive_option(ctx, "flake", flake)
+    operations.run("build-vm-with-bootloader", hosts, ctx.obj["flake"])
 
 
 @infra_rebuild.command()
+@click.pass_context
+@click.option("--flake", help=flake_option_help_text)
 @click.option("--reboot", is_flag=True, help=reboot_option_help_text)
 @click.argument("hosts", nargs=-1)
-def switch(hosts, reboot):
-    operations.run("switch", hosts, reboot)
+def switch(ctx, flake, reboot, hosts):
+    update_recursive_option(ctx, "flake", flake)
+    operations.run("switch", hosts, ctx.obj["flake"], reboot)
 
 
 @infra_rebuild.command()
+@click.pass_context
+@click.option("--flake", help=flake_option_help_text)
 @click.option("--reboot", is_flag=True, help=reboot_option_help_text)
 @click.argument("hosts", nargs=-1)
-def boot(hosts, reboot):
-    operations.run("boot", hosts, reboot)
+def boot(ctx, flake, reboot, hosts):
+    update_recursive_option(ctx, "flake", flake)
+    operations.run("boot", hosts, ctx.obj["flake"], reboot)
 
 
 @infra_rebuild.command()
+@click.pass_context
+@click.option("--flake", help=flake_option_help_text)
 @click.option("--reboot", is_flag=True, help=reboot_option_help_text)
 @click.argument("hosts", nargs=-1)
-def test(hosts, reboot):
-    operations.run("test", hosts, reboot)
+def test(ctx, flake, reboot, hosts):
+    update_recursive_option(ctx, "flake", flake)
+    operations.run("test", hosts, ctx.obj["flake"], reboot)
 
 
 @infra_rebuild.command(short_help=" ", help="This operation is a convenience alias for boot --reboot.")
+@click.pass_context
+@click.option("--flake", help=flake_option_help_text)
 @click.argument("hosts", nargs=-1)
-def reboot(hosts):
-    operations.run("boot", hosts, True)
+def reboot(ctx, flake, hosts):
+    update_recursive_option(ctx, "flake", flake)
+    operations.run("boot", hosts, ctx.obj["flake"], True)

src/infra_rebuild/operations/__init__.py

@@ -6,7 +6,27 @@ import sys
 from infra_rebuild import msg
 
 
-def run(operation, hosts, reboot=False):  # noqa: FBT002 - having reboot as a Boolean positional argument is fine I think # fmt: skip
+def run(operation, hosts, flake_uri, reboot=False):  # noqa: FBT002 - having reboot as a Boolean positional argument is fine I think # fmt: skip
+    try:
+        flake_archive_json = subprocess.run(
+            ["nix", "flake", "archive", "--json", f"{flake_uri}"],  # noqa: S607, S603 - can't know what the users system looks like, maybe do some kind of validation for the flake_uri in the future?
+            capture_output=True,
+            text=True,
+            check=True
+        )  # fmt: skip
+        try:
+            flake_archive = json.loads(flake_archive_json.stdout)
+        except json.JSONDecodeError:
+            msg.error("Internal Error: Couldn't parse the output of \"nix flake archive\".")
+            sys.exit(1)
+
+        if not flake_archive["path"]:
+            msg.error("Internal Error: The \"nix flake archive\" output doesn't include a path.")
+            sys.exit(1)
+    except subprocess.CalledProcessError:
+        msg.error("Error: Couldn't archive the provided flake.")
+        sys.exit(1)
+
     match operation:
         case "build" | "build-vm" | "build-vm-with-bootloader":
             act_remotely = False
@@ -22,23 +42,23 @@ def run(operation, hosts, reboot=False):  # noqa: FBT002 - having reboot as a Bo
             continue
 
         if act_remotely:
-            remote(operation, host, reboot)
+            remote(operation, host, flake_archive, reboot)
         else:
-            local(operation, host)
+            local(operation, host, flake_archive)
 
 
-def local(operation, host):
+def local(operation, host, flake_archive):
     msg.info(f"Running nixos-rebuild {operation} for {host}...")
     subprocess.run(
-        ["nixos-rebuild", operation, "--flake", f".#{host}"],  # noqa: S607, S603 - can't know what the users system looks like, maybe do some kind of validation for the given host in the future?
+        ["nixos-rebuild", operation, "--flake", f"{flake_archive['path']}#{host}"],  # noqa: S607, S603 - can't know what the users system looks like, maybe do some kind of validation for the given host in the future?
         check=False
     )  # fmt: skip
 
 
-def remote(operation, host, reboot=False):  # noqa: FBT002 - having reboot as a Boolean positional argument is fine I think # fmt: skip
+def remote(operation, host, flake_archive, reboot=False):  # noqa: FBT002 - having reboot as a Boolean positional argument is fine I think # fmt: skip
     config = None
     try:
-        with open("deployment_configuration.json") as config_file:
+        with open(f"{flake_archive['path']}/deployment_configuration.json") as config_file:
             try:
                 config = json.load(config_file)
             except json.JSONDecodeError:
@@ -62,7 +82,7 @@ def remote(operation, host, reboot=False):  # noqa: FBT002 - having reboot as a
             pass
     if not target_hostname:
         nix_config_fqdn = subprocess.run(
-            ["nix", "eval", "--raw", f".#nixosConfigurations.{host}.config.networking.fqdn"],  # noqa: S607, S603 - can't know what the users system looks like, maybe do some kind of validation for host in the future?
+            ["nix", "eval", "--raw", f"{flake_archive['path']}#nixosConfigurations.{host}.config.networking.fqdn"],  # noqa: S607, S603 - can't know what the users system looks like, maybe do some kind of validation for host in the future?
             capture_output=True,
             text=True,
             check=False,
@@ -119,7 +139,7 @@ def remote(operation, host, reboot=False):  # noqa: FBT002 - having reboot as a
         msg.info(f"Running nixos-rebuild {operation} for {host} on {target_host}...")
 
     nixos_rebuild = subprocess.run(
-        ["nixos-rebuild", operation, "--flake", f".#{host}", "--target-host", target_host, "--use-substitutes", "--use-remote-sudo"],  # noqa: S607, S603, E501 - can't know what the users system looks like, maybe do some kind of validation for the given host in the future?, not breaking up the command makes it more readable
+        ["nixos-rebuild", operation, "--flake", f"{flake_archive['path']}#{host}", "--target-host", target_host, "--use-substitutes", "--use-remote-sudo"],  # noqa: S607, S603, E501 - can't know what the users system looks like, maybe do some kind of validation for the given host in the future?, not breaking up the command makes it more readable
         env=nixos_rebuild_env,
         check=False,
     )  # fmt: skip