feat(push): relay notifications as encrypted web push (#2906)

fluxer_push/src/cli.rs

@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+use crate::config::{Config, Mode};
+use anyhow::Context as _;
+use clap::{Parser, Subcommand};
+use std::net::IpAddr;
+
+#[derive(Debug, Parser)]
+#[command(name = "fluxer-push", disable_help_subcommand = true)]
+pub struct Args {
+    #[arg(long = "mode", value_name = "MODE", value_enum, default_value_t = Mode::Delivery, global = true)]
+    pub mode: Mode,
+
+    #[arg(long = "bind-host", value_name = "HOST")]
+    pub bind_host: Option<String>,
+
+    #[arg(long = "port", value_name = "PORT")]
+    pub port: Option<u16>,
+
+    #[command(subcommand)]
+    pub command: Option<Command>,
+}
+
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Subcommand)]
+pub enum Command {
+    Healthcheck,
+}
+
+pub fn load_config(args: &Args) -> anyhow::Result<Config> {
+    load_config_from_iter(args, std::env::vars())
+}
+
+fn load_config_from_iter<I, K, V>(args: &Args, vars: I) -> anyhow::Result<Config>
+where
+    I: IntoIterator<Item = (K, V)>,
+    K: Into<String>,
+    V: Into<String>,
+{
+    let mut cfg = Config::load_from_iter(args.mode, vars)?;
+    apply_overrides(args, &mut cfg)?;
+    Ok(cfg)
+}
+
+fn apply_overrides(args: &Args, cfg: &mut Config) -> anyhow::Result<()> {
+    let bind_addr = cfg.bind_addr_mut();
+    if let Some(bind_host) = args.bind_host.as_deref() {
+        let bind_host = bind_host.trim();
+        anyhow::ensure!(!bind_host.is_empty(), "--bind-host cannot be empty");
+        bind_addr.set_ip(
+            bind_host
+                .parse::<IpAddr>()
+                .with_context(|| format!("--bind-host is not an IP address: {bind_host}"))?,
+        );
+    }
+    if let Some(port) = args.port {
+        bind_addr.set_port(port);
+    }
+    Ok(())
+}