add watch command

Cargo.lock

@@ -513,6 +513,8 @@ dependencies = [
  "steam-vent",
  "thiserror 2.0.12",
  "tokio",
+ "tracing",
+ "tracing-subscriber",
  "vdf-reader",
 ]
 
@@ -1245,6 +1247,16 @@ dependencies = [
  "minimal-lexical",
 ]
 
+[[package]]
+name = "nu-ansi-term"
+version = "0.46.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77a8165726e8236064dbb45459242600304b42a5ea24ee2948e18e023bf7ba84"
+dependencies = [
+ "overload",
+ "winapi",
+]
+
 [[package]]
 name = "num"
 version = "0.3.1"
@@ -1396,6 +1408,12 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "04744f49eae99ab78e0d5c0b603ab218f515ea8cfe5a456d7629ad883a3b6e7d"
 
+[[package]]
+name = "overload"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b15813163c1d831bf4a13c3610c05c0d03b39feb07f7e09fa234dac9b15aaf39"
+
 [[package]]
 name = "parking_lot_core"
 version = "0.9.11"
@@ -1977,6 +1995,15 @@ dependencies = [
  "digest",
 ]
 
+[[package]]
+name = "sharded-slab"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f40ca3c46823713e0d4209592e8d6e826aa57e928f09752619fc696c499637f6"
+dependencies = [
+ "lazy_static",
+]
+
 [[package]]
 name = "shlex"
 version = "1.3.0"
@@ -2255,6 +2282,15 @@ dependencies = [
  "syn 2.0.103",
 ]
 
+[[package]]
+name = "thread_local"
+version = "1.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f60246a4944f24f6e018aa17cdeffb7818b76356965d03b07d6a9886e8962185"
+dependencies = [
+ "cfg-if",
+]
+
 [[package]]
 name = "tinystr"
 version = "0.8.1"
@@ -2449,6 +2485,32 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b9d12581f227e93f094d3af2ae690a574abb8a2b9b7a96e7cfe9647b2b617678"
 dependencies = [
  "once_cell",
+ "valuable",
+]
+
+[[package]]
+name = "tracing-log"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee855f1f400bd0e5c02d150ae5de3840039a3f54b025156404e34c23c03f47c3"
+dependencies = [
+ "log",
+ "once_cell",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-subscriber"
+version = "0.3.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e8189decb5ac0fa7bc8b96b7cb9b2701d60d48805aca84a238004d665fcc4008"
+dependencies = [
+ "nu-ansi-term",
+ "sharded-slab",
+ "smallvec",
+ "thread_local",
+ "tracing-core",
+ "tracing-log",
 ]
 
 [[package]]
@@ -2530,6 +2592,12 @@ version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
 
+[[package]]
+name = "valuable"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ba73ea9cf16a25df0c8caa16c51acb937d5712a8429db78a3ee29d5dcacd3a65"
+
 [[package]]
 name = "vdf-reader"
 version = "0.3.1"
@@ -2694,6 +2762,28 @@ dependencies = [
  "rustix",
 ]
 
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
 [[package]]
 name = "windows-sys"
 version = "0.48.0"

Cargo.toml

@@ -14,3 +14,5 @@ tokio = { version = "1.45.1", features = ["macros", "rt-multi-thread"] }
 main_error = "0.1.2"
 clap = { version = "4.5.40", features = ["derive"] }
 serde_json = "1.0.140"
+tracing = "0.1.41"
+tracing-subscriber = "0.3.19"

src/main.rs

@@ -1,8 +1,12 @@
-use crate::prefetch::prefetch;
+use std::process::Command;
+use std::time::Duration;
+use crate::prefetch::{prefetch, PrefetchError};
 use crate::product_info::{ProductInfoError, ProductInfoFetcher};
 use clap::Parser;
 use main_error::MainResult;
 use serde::Serialize;
+use tokio::time::sleep;
+use tracing::{debug, error, info};
 
 mod error;
 mod prefetch;
@@ -11,15 +15,17 @@ mod product_info;
 #[derive(Debug, Parser)]
 struct Args {
     #[command(subcommand)]
-    command: Command,
+    command: ArgsCommand,
 }
 
 #[derive(Debug, Parser)]
-enum Command {
+enum ArgsCommand {
     /// Get the latest manifest and pre-fetch it
     Fetch(ProductArgs),
     /// Get the latest manifest without fetching
     Manifest(ProductArgs),
+    /// Watch for manifest changes and pre-fetch any updates
+    Watch(WatchArgs),
 }
 
 #[derive(Debug, Parser)]
@@ -34,32 +40,68 @@ struct ProductArgs {
     depot: Vec<u32>,
 }
 
+#[derive(Debug, Parser)]
+struct WatchArgs {
+    #[clap(flatten)]
+    product_args: ProductArgs,
+    /// How often to check for updates
+    #[clap(long, default_value_t = 300)]
+    interval: u64,
+    /// Command to run when updates are detected, the manifest data will be passed as the first argument as json.
+    #[clap(long)]
+    run: Option<String>,
+}
+
 #[tokio::main]
 async fn main() -> MainResult {
     let args = Args::parse();
+    tracing_subscriber::fmt::init();
 
     let info_fetcher = ProductInfoFetcher::new().await?;
 
     match args.command {
-        Command::Fetch(args) => {
+        ArgsCommand::Fetch(args) => {
             let inputs = get_manifests(&info_fetcher, &args).await?;
-            let outputs = inputs.into_iter()
+            let outputs = fetch_inputs(inputs)?;
-                .map(|input| {
-                    prefetch(&input).map(|hash| ManifestOutput {
-                        app_id: input.app_id,
-                        depot_id: input.depot_id,
-                        manifest: input.manifest,
-                        hash,
-                    })
-                })
-                .collect::<Result<Vec<_>, _>>()?;
 
             serde_json::to_writer_pretty(std::io::stdout(), &outputs)?;
         }
-        Command::Manifest(args) => {
+        ArgsCommand::Manifest(args) => {
             let inputs = get_manifests(&info_fetcher, &args).await?;
             serde_json::to_writer_pretty(std::io::stdout(), &inputs)?;
         }
+        ArgsCommand::Watch(args) => {
+            let mut last_inputs = get_manifests(&info_fetcher, &args.product_args).await?;
+
+            loop {
+                sleep(Duration::from_secs(args.interval)).await;
+                let new_inputs = get_manifests(&info_fetcher, &args.product_args).await?;
+                if new_inputs != last_inputs {
+                    last_inputs = new_inputs.clone();
+                    let inputs_json = serde_json::to_string(&new_inputs)?;
+                    debug!(inputs = inputs_json, "updated detected");
+
+                    let outputs = fetch_inputs(new_inputs)?;
+                    let output_json = serde_json::to_string(&outputs)?;
+                    info!(outputs = ?output_json, "prefetch complete");
+
+                    if let Some(run) = args.run.as_deref() {
+                        match Command::new(run)
+                            .arg(output_json)
+                            .status() {
+                            Ok(status) => {
+                                info!(%status, "Command existed");
+                            }
+                            Err(error) => {
+                                error!(%error, "Failed to run command");
+                            }
+                        }
+                    }
+                }
+
+            }
+
+        }
     }
 
     Ok(())
@@ -91,7 +133,19 @@ async fn get_manifests(
         .collect())
 }
 
-#[derive(Debug, Serialize)]
+fn fetch_inputs(inputs: impl IntoIterator<Item = ManifestInput>) -> Result<Vec<ManifestOutput>, PrefetchError> {
+    inputs.into_iter()
+        .map(|input| {
+            prefetch(&input).map(|hash| ManifestOutput {
+                app_id: input.app_id,
+                depot_id: input.depot_id,
+                manifest: input.manifest,
+                hash,
+            })
+        }).collect()
+}
+
+#[derive(Debug, Serialize, Eq, PartialEq, Copy, Clone)]
 struct ManifestInput {
     app_id: u32,
     depot_id: u32,