add file-list option

src/main.rs

@@ -21,13 +21,22 @@ struct Args {
 #[derive(Debug, Parser)]
 enum ArgsCommand {
     /// Get the latest manifest and pre-fetch it
-    Fetch(ProductArgs),
+    Fetch(FetchArgs),
     /// Get the latest manifest without fetching
     Manifest(ProductArgs),
     /// Watch for manifest changes and pre-fetch any updates
     Watch(WatchArgs),
 }
 
+#[derive(Debug, Parser)]
+struct FetchArgs {
+    #[clap(flatten)]
+    product_args: ProductArgs,
+    /// Only download specific files, either raw files names, or regexes prefixed with 'regex:'
+    #[clap(long)]
+    file_list: Vec<String>,
+}
+
 #[derive(Debug, Parser)]
 struct ProductArgs {
     /// App to prefetch depots for
@@ -50,6 +59,9 @@ struct WatchArgs {
     /// Command to run when updates are detected, the manifest data will be passed as the first argument as json.
     #[clap(long)]
     run: Option<String>,
+    /// Only download specific files, either raw files names, or regexes prefixed with 'regex:'
+    #[clap(long)]
+    file_list: Vec<String>,
 }
 
 #[tokio::main]
@@ -61,8 +73,8 @@ async fn main() -> MainResult {
 
     match args.command {
         ArgsCommand::Fetch(args) => {
-            let inputs = get_manifests(&info_fetcher, &args).await?;
-            let outputs = fetch_inputs(inputs)?;
+            let inputs = get_manifests(&info_fetcher, &args.product_args).await?;
+            let outputs = fetch_inputs(inputs, &args.file_list)?;
 
             serde_json::to_writer_pretty(std::io::stdout(), &outputs)?;
         }
@@ -81,7 +93,7 @@ async fn main() -> MainResult {
                     let inputs_json = serde_json::to_string(&new_inputs)?;
                     debug!(inputs = inputs_json, "updated detected");
 
-                    let outputs = fetch_inputs(new_inputs)?;
+                    let outputs = fetch_inputs(new_inputs, &args.file_list)?;
                     let output_json = serde_json::to_string(&outputs)?;
                     info!(outputs = ?output_json, "prefetch complete");
 
@@ -133,10 +145,10 @@ async fn get_manifests(
         .collect())
 }
 
-fn fetch_inputs(inputs: impl IntoIterator<Item = ManifestInput>) -> Result<Vec<ManifestOutput>, PrefetchError> {
+fn fetch_inputs(inputs: impl IntoIterator<Item = ManifestInput>, file_list: &[String]) -> Result<Vec<ManifestOutput>, PrefetchError> {
     inputs.into_iter()
         .map(|input| {
-            prefetch(&input).map(|hash| ManifestOutput {
+            prefetch(&input, file_list).map(|hash| ManifestOutput {
                 app_id: input.app_id,
                 depot_id: input.depot_id,
                 manifest: input.manifest,

src/prefetch.rs

@@ -1,4 +1,5 @@
 use crate::ManifestInput;
+use itertools::Itertools;
 use std::process::Command;
 use std::string::FromUtf8Error;
 use thiserror::Error;
@@ -23,14 +24,22 @@ in fetchSteam {
   depotId = "DEPOT_ID";
   manifestId = "MANIFEST_ID";
   hash = "";
+  fileList = [FILE_LIST];
 }
     "#;
 
-pub fn prefetch(manifest: &ManifestInput) -> Result<String, PrefetchError> {
+pub fn prefetch(manifest: &ManifestInput, file_list: &[String]) -> Result<String, PrefetchError> {
+    let file_list_nix = file_list
+        .iter()
+        .map(|filter| serde_json::to_string(filter).unwrap_or_default())
+        .join(" ");
+    dbg!(&file_list_nix);
+
     let expression = EXPRESSION_TEMPLATE
         .replace("APP_ID", &manifest.app_id.to_string())
         .replace("DEPOT_ID", &manifest.depot_id.to_string())
-        .replace("MANIFEST_ID", &manifest.manifest.to_string());
+        .replace("MANIFEST_ID", &manifest.manifest.to_string())
+        .replace("FILE_LIST", &file_list_nix);
 
     let command = Command::new("nix-build")
         .arg("-E")