kvarn/ctl.rs
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//! Control the Kvarn server from the outside.
//!
//! [`Plugin`]s can be added using [`RunConfig::add_plugin`].
use crate::prelude::*;
/// The arguments passed by `kvarnctl` to a [`Plugin`].
#[derive(Debug, Clone)]
pub struct Arguments {
name: String,
args: Vec<String>,
}
impl Arguments {
/// Get a reference to the name of this request.
/// This will be the same as your plugin's name.
#[must_use]
pub fn name(&self) -> &str {
self.name.as_ref()
}
/// Get a reference to the arguments.
pub fn iter(&self) -> impl Iterator<Item = &str> {
self.args.iter().map(String::as_str)
}
}
/// The kind of response to send back to `kvarnctl`.
/// See [`PluginResponse`] for more details.
#[derive(Debug, Clone)]
pub enum PluginResponseKind {
/// The request was executed without errors.
Ok {
/// The optional response data.
data: Option<Vec<u8>>,
},
/// The request failed to execute.
Error {
/// The optional response data.
data: Option<Vec<u8>>,
},
}
/// A response in reply to the [request](Arguments) `kvarnctl` sent.
pub struct PluginResponse {
/// The kind of response.
pub kind: PluginResponseKind,
/// If the socket should be closed. Should ONLY be used when we are immediately shutting down.
pub close: bool,
/// A function to run after sending the response.
pub post_send: Option<Box<dyn FnOnce() + Send + Sync>>,
}
impl PluginResponse {
/// Creates a new response which doesn't close the connection.
#[must_use]
pub fn new(kind: PluginResponseKind) -> Self {
Self {
kind,
close: false,
post_send: None,
}
}
/// Creates a new OK response with content.
#[must_use]
pub fn ok(data: impl Into<Vec<u8>>) -> Self {
Self::new(PluginResponseKind::Ok {
data: Some(data.into()),
})
}
/// Creates a new OK response without content.
#[must_use]
pub fn ok_empty() -> Self {
Self::new(PluginResponseKind::Ok { data: None })
}
/// Creates a new response signalling an error, with content.
#[must_use]
pub fn error(data: impl Into<Vec<u8>>) -> Self {
Self::new(PluginResponseKind::Error {
data: Some(data.into()),
})
}
/// Creates a new response signalling an error, without content.
#[must_use]
pub fn error_empty() -> Self {
Self::new(PluginResponseKind::Error { data: None })
}
/// Close the ctl socket after this is returned.
/// Use this only is you shut Kvarn down immediately in your plugin.
#[must_use]
pub fn close(mut self) -> Self {
self.close = true;
self
}
/// Add a callback to fun after the response is sent.
#[must_use]
pub fn post_send(mut self, f: impl FnOnce() + Send + Sync + 'static) -> Self {
self.post_send = Some(Box::new(f));
self
}
}
impl Debug for PluginResponse {
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
let mut s = f.debug_struct(utils::ident_str!(PluginResponse));
utils::fmt_fields!(
s,
(self.kind),
(self.close),
(
self.post_send,
&self.post_send.as_ref().map(|_| "[fn]".as_clean())
)
);
s.finish()
}
}
/// A plugin, similar to the [`extensions`].
/// One can easily be constructed using the [`plugin!`] macro.
///
/// # Examples
///
/// ```
/// # use kvarn::prelude::*;
/// let mut config = RunConfig::new();
/// let plugin: ctl::Plugin = Box::new(|args, _port_descriptors, _shutdown_manager, _plugins| {
/// Box::pin(async move {
/// let mut s = args.name().to_owned();
/// for arg in args.iter() {
/// s.push(' ');
/// s.push_str(arg);
/// }
/// ctl::PluginResponse::ok(s)
/// }) as extensions::RetSyncFut<'_, _>
/// });
/// config = config.add_plugin("my-plugin", plugin);
/// ```
pub type Plugin = Box<
dyn for<'a> Fn(
Arguments,
&'a Vec<PortDescriptor>,
&'a shutdown::Manager,
&'a Plugins,
) -> RetSyncFut<'a, PluginResponse>
+ Send
+ Sync,
>;
/// Check if `args` has no arguments. If that's the case, an error with the appropriate
/// [`PluginResponse`] is returned. Use the `if let Err()` pattern to easily return.
#[allow(clippy::missing_errors_doc)]
pub fn check_no_arguments(args: &Arguments) -> Result<(), PluginResponse> {
if args.args.is_empty() {
Ok(())
} else {
Err(PluginResponse {
kind: PluginResponseKind::Error {
data: Some("no arguments were expected".into()),
},
close: false,
post_send: None,
})
}
}
/// The plugins this Kvarn instance supports.
///
/// All plugins added by [`RunConfig::add_plugin`] are available to [`Plugin`]s in runtime.
///
/// # Defaults
///
/// More info can be found at [kvarn.org](https://kvarn.org/ctl/).
///
/// ## `shutdown`
///
/// If the [feature](https://kvarn.org/cargo-features.) `graceful-shutdown` is enabled, a plugin with the name `shutdown` is
/// added. It's functionality can be changed by adding a new plugin with the same name.
///
/// ## `ping`
///
/// The `ping` plugin sends back all the args we received.
///
/// ## `reload`
///
/// Starts a new instance of Kvarn which takes control.
/// Requires a `shutdown` plugin to be present and
/// [handover support](https://kvarn.org/shutdown-handover.#handover).
///
/// If handover isn't supported, there will be a few milliseconds where no one's listening
/// on the port.
///
/// ## `wait`
///
/// Waits for the Kvarn instance to shut down.
///
/// ## `clear`
///
/// Format: `kvarnctl clear <method> (<host> <file/URI>)`
///
/// Clears caches. Methods available are `all`, `files`, `responses`,
/// and two which clear a specific resource, `file` and `response`.
pub struct Plugins {
plugins: HashMap<String, Plugin>,
// remember to add fields to debug implementation
}
impl Debug for Plugins {
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
let name = utils::ident_str!(Plugins);
let mut s = f.debug_struct(name);
utils::fmt_fields!(
s,
(
self.plugins,
&self
.plugins
.keys()
.map(|key| (key, "[ opaque plugin ]".as_clean()))
.collect::<HashMap<_, _>>()
)
);
s.finish()
}
}
impl Plugins {
// constructors
pub(crate) fn new() -> Self {
let mut me = Self::empty();
#[cfg(feature = "graceful-shutdown")]
me.with_shutdown();
me.with_ping().with_reload().with_wait().with_clear();
me
}
pub(crate) fn empty() -> Self {
Self {
plugins: HashMap::new(),
}
}
// add plugins
pub(crate) fn add_plugin(&mut self, name: impl AsRef<str>, plugin: Plugin) -> &mut Self {
self.plugins.insert(name.as_ref().to_owned(), plugin);
self
}
#[cfg(feature = "graceful-shutdown")]
pub(crate) fn with_shutdown(&mut self) -> &mut Self {
self.add_plugin(
"shutdown",
plugin!(|args, _, shutdown, _| {
let mut iter = args.iter();
let arg = iter.next();
let no_wait;
match arg {
Some("no-wait") => no_wait = true,
None => no_wait = false,
Some(arg) => {
return PluginResponse::error(format!("unexpected argument: {arg:?}"))
}
}
if iter.next().is_some() {
return PluginResponse::error("unexpected argument");
}
// we register (with the call to `wait_for_pre_shutdown`),
// then shut down, then wait.
// If we shut down before registering, we could hang forever
let sender = if no_wait {
None
} else {
Some(shutdown.wait_for_pre_shutdown())
};
shutdown.shutdown();
let sender = if let Some(sender) = sender {
Some(sender.await)
} else {
None
};
PluginResponse::ok("'Successfully completed a graceful shutdown.'")
.close()
.post_send(move || {
if let Some(sender) = sender {
sender.send(()).expect("failed to shut down");
}
})
}),
);
self
}
pub(crate) fn with_ping(&mut self) -> &mut Self {
self.add_plugin(
"ping",
plugin!(|args, _, _, _| {
let mut data = args.args.iter().fold(String::new(), |mut acc, arg| {
acc.push(' ');
utils::encode_quoted_str(arg, &mut acc);
acc
});
// remove first space
if !data.is_empty() {
data.remove(0);
}
PluginResponse::ok(data)
}),
);
self
}
pub(crate) fn with_reload(&mut self) -> &mut Self {
self.add_plugin(
"reload",
plugin!(|args, _, shutdown, plugins| {
let mut arg_iter = args.iter();
let wait = arg_iter.next() == Some("wait") && arg_iter.next().is_none();
if !wait {
if let Err(r) = check_no_arguments(&args) {
return r;
}
}
if !plugins.contains_plugin("shutdown") {
return PluginResponse::error(
"No shutdown plugin was found. It is required for reload.",
);
}
let executable = std::env::args_os()
.next()
.ok_or_else(|| io::Error::new(io::ErrorKind::NotFound, "executable not found"));
let program = match executable {
Ok(p) => p,
Err(err) => {
error!("Could not reload - arg0 isn't found: {err}");
return PluginResponse::error(format!("arg0 isn't found: {err}"));
}
};
let mut command = std::process::Command::new(program);
command
.args(std::env::args_os().skip(1))
.stdin(std::process::Stdio::inherit());
if let Ok(cwd) = std::env::current_dir() {
command.current_dir(cwd);
}
let mut _child = match command.spawn() {
Ok(c) => c,
Err(err) => {
error!("Failed to spawn child when reloading: {err}");
return PluginResponse::error(format!("failed to spawn child: {err}"));
}
};
let sender = if wait {
Some(shutdown.wait_for_pre_shutdown().await)
} else {
None
};
PluginResponse::ok("successfully reloaded Kvarn").post_send(move || {
if let Some(s) = sender {
s.send(()).unwrap();
}
})
}),
);
self
}
pub(crate) fn with_wait(&mut self) -> &mut Self {
self.add_plugin(
"wait",
plugin!(|args, _, shutdown, _| {
if let Err(r) = check_no_arguments(&args) {
return r;
}
let sender = shutdown.wait_for_pre_shutdown().await;
sender.send(()).unwrap();
PluginResponse::ok_empty()
}),
);
self
}
pub(crate) fn with_clear(&mut self) -> &mut Self {
self.add_plugin(
"clear",
plugin!(|args, ports, _, _| {
let mut args = args.iter();
let msg = match args.next() {
Some("all") => {
let host = args.next();
for hosts in ports.iter().map(PortDescriptor::hosts) {
hosts.clear_response_caches(host).await;
hosts.clear_file_caches(host).await;
}
if let Some(host) = host {
format!("cleared the caches on {host}")
} else {
"cleared all caches".to_owned()
}
}
Some("files") => {
let host = args.next();
for hosts in ports.iter().map(PortDescriptor::hosts) {
hosts.clear_file_caches(host).await;
}
if let Some(host) = host {
format!("cleared the file cache on {host}")
} else {
"cleared all file caches".to_owned()
}
}
Some("responses") => {
let host = args.next();
for hosts in ports.iter().map(PortDescriptor::hosts) {
hosts.clear_response_caches(host).await;
}
if let Some(host) = host {
format!("cleared the response cache on {host}")
} else {
"cleared all response caches".to_owned()
}
}
Some("file") => {
let host = if let Some(a) = args.next() {
a
} else {
return PluginResponse::error(
"please supply the host you want to clear the response from",
);
};
let path = if let Some(a) = args.next() {
a
} else {
return PluginResponse::error(
"please supply response you want to clear after the host",
);
};
let mut cleared = false;
let mut found = false;
for hosts in ports.iter().map(PortDescriptor::hosts) {
let (f, c) = hosts.clear_file(host, path);
cleared = cleared || c;
found = found || f;
}
if !found {
// \\' so it isn't removed by the shell parsing
return PluginResponse::error(
"didn't find the target host. \
Use \\'default\\' for the default host",
);
} else if !cleared {
return PluginResponse::error("target file isn\\'t in the cache");
}
format!("cleared {path:?} from {host:?}")
}
Some("response") => {
let host = if let Some(a) = args.next() {
a
} else {
return PluginResponse::error(
"please supply the host you want to clear the response from",
);
};
let response = if let Some(a) = args.next() {
a
} else {
return PluginResponse::error(
"please supply response you want to clear after the host",
);
};
let uri = match Uri::builder().path_and_query(response).build() {
Ok(uri) => uri,
Err(..) => {
return PluginResponse::error("failed to format target response");
}
};
let mut cleared = false;
let mut found = false;
for hosts in ports.iter().map(PortDescriptor::hosts) {
let (f, c) = hosts.clear_page(host, &uri);
cleared = cleared || c;
found = found || f;
}
if !found {
return PluginResponse::error(
"didn't find the target host. Use 'default' for the default host",
);
} else if !cleared {
return PluginResponse::error("target response isn't in the cache");
}
format!("cleared {response:?} from {host:?}")
}
Some(_) => return PluginResponse::error("clear method invalid"),
None => return PluginResponse::error("you must specify what to clear"),
};
if args.next().is_some() {
return PluginResponse::error("unexpected argument");
}
PluginResponse::ok(msg)
}),
)
}
// public getters
/// Check if plugin with `name` is present.
/// This means it can be called from `kvarnctl`.
#[must_use]
pub fn contains_plugin(&self, name: impl AsRef<str>) -> bool {
self.plugins.contains_key(name.as_ref())
}
/// Get an iterator of all the plugins attached to this instance.
/// All of the returned names are commands which can be called from `kvarnctl`.
pub fn iter(&self) -> impl Iterator<Item = &str> + Send + Sync + '_ {
self.plugins.keys().map(String::as_str)
}
}
impl Default for Plugins {
fn default() -> Self {
Self::new()
}
}
/// Create a [`Plugin`].
///
/// # Examples
///
/// ```
/// # use kvarn::prelude::*;
/// use ctl::*;
/// let mut config = RunConfig::new();
/// config.add_plugin(
/// "wait",
/// plugin!(|args, _, shutdown, _| {
/// if let Err(r) = check_no_arguments(&args) {
/// return r;
/// }
/// shutdown.wait().await;
/// PluginResponse::ok_empty()
/// })
/// );
#[macro_export]
macro_rules! plugin {
(|$args:tt, $ports:tt, $shutdown:tt, $plugins:tt $(,)?| $code:block ) => {{
Box::new(|$args, $ports, $shutdown, $plugins| {
Box::pin(async move { $code }) as $crate::extensions::RetSyncFut<'_, _>
})
}};
}
/// Default message path.
#[allow(unused_assignments)]
pub(crate) fn socket_path() -> PathBuf {
let mut p = Path::new("/run").to_path_buf();
#[cfg(all(unix, target_os = "macos"))]
{
p = std::env::var_os("HOME")
.map_or_else(|| Path::new("/Library/Caches").to_path_buf(), Into::into);
}
#[cfg(all(unix, not(target_os = "macos")))]
{
let user: u32 = unsafe { libc::getuid() };
if user != 0 {
p.push("user");
p.push(user.to_string());
}
}
p.push("kvarn.sock");
p
}
/// Initiates the handover from a old instance to the one currently running, if the
/// `graceful-shutdown` feature is enabled. Else, just opens the socket at `path`.
/// [`socket_path`] is the fallback.
///
/// This sends a `shutdown` message, waits for a reply, and then starts listening.
///
/// This doesn't resolve until the last instance was shut down.
#[cfg_attr(windows, allow(unused_variables))]
pub(crate) async fn listen(
plugins: Plugins,
ports: Arc<Vec<PortDescriptor>>,
shutdown: Arc<shutdown::Manager>,
path: impl Into<PathBuf>,
) {
#[cfg(unix)]
{
let path = path.into();
let supports_shutdown = plugins.plugins.contains_key("shutdown");
info!("try send shutdown to previous instance");
if supports_shutdown {
match kvarn_signal::unix::send_to(b"shutdown no-wait".to_vec(), &path)
.await
.as_deref()
{
// continue normally
kvarn_signal::unix::Response::Data(data) if data.starts_with(b"ok") => {
info!("Old instance is shutting down");
}
kvarn_signal::unix::Response::NotFound => {}
kvarn_signal::unix::Response::Data(data) => {
error!(
"Got unexpected reply from previous Kvarn instance: {:?}. \
Will not be listening for kvarnctl messages.",
str::from_utf8(data).unwrap_or("[binary]")
);
return;
}
kvarn_signal::unix::Response::Error => {
error!(
"Failed to message previous Kvarn instance. \
It might still be running or \
you don't have sufficient privileges to remove leftovers from previous instance. \
Will not be listening for kvarnctl messages."
);
return;
}
};
}
let plugins = Arc::new(plugins);
#[cfg(feature = "graceful-shutdown")]
let sd = shutdown.clone();
#[allow(unused_variables)]
let (overriden, close_ctl) = kvarn_signal::unix::start_at(
move |data| {
let plugins = Arc::clone(&plugins);
let shutdown = Arc::clone(&shutdown);
let ports = Arc::clone(&ports);
Box::pin(async move {
let data = &data;
let data = if let Ok(s) = str::from_utf8(data) {
s
} else {
return kvarn_signal::unix::HandlerResponse {
data: "error Received binary content. Requests have to be UTF-8."
.into(),
close: false,
post_send: None,
};
};
let mut iter = utils::quoted_str_split(data);
let name = iter.next().unwrap_or_default();
let args = iter.collect();
let arguments = Arguments { name, args };
if let Some(plugin) = plugins.plugins.get(arguments.name()) {
let response = (plugin)(arguments, &ports, &shutdown, &plugins).await;
let (data, prepend) = match response.kind {
PluginResponseKind::Error { data } => {
if let Some(data) = data.as_deref() {
warn!(
"Encountered error on kvarnctl socket: {:?}",
String::from_utf8_lossy(data)
);
} else {
warn!("Encountered error on kvarnctl socket.");
}
(data, "error")
}
PluginResponseKind::Ok { data } => (data, "ok"),
};
let mut data = data.unwrap_or_default();
let len = prepend.len() + usize::from(!data.is_empty());
(0..len).for_each(|_| data.insert(0, b' '));
data[..prepend.len()].copy_from_slice(prepend.as_bytes());
kvarn_signal::unix::HandlerResponse {
data,
close: response.close,
post_send: response.post_send,
}
} else {
warn!("Got unexpected message on socket: {:?}", data,);
kvarn_signal::unix::HandlerResponse {
data: Vec::from("error 'Command not found.'"),
close: false,
post_send: None,
}
}
}) as RetSyncFut<'_, kvarn_signal::unix::HandlerResponse>
},
path,
)
.await;
#[cfg(feature = "graceful-shutdown")]
let _task = spawn(async move {
drop(sd.get_initate_shutdown_watcher().changed().await);
info!("Send close to ctl socket, because we started shutting down.");
let _ = close_ctl.send(true);
})
.await;
if overriden {
if supports_shutdown {
info!("Removed old kvarnctl socket.");
} else {
warn!("Removed old kvarnctl socket. The other instance might still be running. \
Consider adding a `shutdown` plugin or enabling the `graceful-shutdown` cargo feature.");
}
}
}
#[cfg(windows)]
{
warn!("Trying to listen for kvarnctl messages on an unsupported platform. Currently, UNIX is supported.");
}
}