feat: Add initial extractor loader

Author: GeekMasher

src/extractors.rs

@@ -0,0 +1,75 @@
+use std::path::PathBuf;
+
+use anyhow::Result;
+use ghastoolkit::codeql::CodeQLExtractor;
+use ghastoolkit::Repository;
+use octocrab::models::repos::{Asset, Release};
+
+async fn fetch_releases(client: &octocrab::Octocrab, repository: &Repository) -> Result<Release> {
+    let release = if let Some(rel) = repository.reference() {
+        client
+            .repos(repository.owner(), repository.name())
+            .releases()
+            .get_by_tag(rel)
+            .await?
+    } else {
+        // Get Latest Release
+        client
+            .repos(repository.owner(), repository.name())
+            .releases()
+            .get_latest()
+            .await?
+    };
+
+    log::debug!("Release :: {} - {:?}", release.tag_name, release.created_at);
+
+    Ok(release)
+}
+
+/// Fetch the CodeQL Extractor from the repository
+///
+/// Finds the correct asset based on ending in `.tar.gz`.
+pub async fn fetch_extractor(
+    client: &octocrab::Octocrab,
+    repository: &Repository,
+    output: &PathBuf,
+) -> Result<CodeQLExtractor> {
+    let release = fetch_releases(client, repository).await?;
+
+    let Some(release_asset) = release.assets.iter().find(|a| a.name.ends_with(".tar.gz")) else {
+        return Err(anyhow::anyhow!("No asset found"));
+    };
+    log::info!("Asset URL :: {}", release_asset.browser_download_url);
+
+    let asset: Asset = client.get(release_asset.url.clone(), None::<&()>).await?;
+
+    let extractor_tarball = output.join("extractor.tar.gz");
+    let extractor_path = output.join("extractor-pack").join("codeql-extractor.yml");
+
+    let toolcache = ghactions::ToolCache::new();
+
+    if !extractor_tarball.exists() {
+        log::info!("Downloading asset to {:?}", extractor_tarball);
+
+        toolcache.download_asset(&asset, &extractor_tarball).await?;
+    }
+
+    if extractor_path.exists() {
+        log::info!("Removing existing asset {:?}", extractor_path);
+        std::fs::remove_dir_all(&extractor_path)?;
+    }
+
+    log::info!("Extracting asset to {:?}", extractor_path);
+    toolcache
+        .extract_archive(&extractor_tarball, &output)
+        .await?;
+
+    if !extractor_path.exists() {
+        return Err(anyhow::anyhow!("Extractor not found"));
+    }
+
+    log::info!("Loading CodeQL Extractor from {:?}", extractor_path);
+    let extractor = CodeQLExtractor::load_path(extractor_path)?;
+
+    Ok(extractor)
+}