feat: respect RATTLER_AUTH_FILE when using AuthenticationStorage::default()

Cargo.toml

@@ -129,6 +129,7 @@ sysinfo = "0.30.10"
 tar = "0.4.40"
 tempdir = "0.3.7"
 tempfile = "3.10.1"
+temp-env = "0.3.6"
 test-log = "0.2.15"
 thiserror = "1.0"
 tokio = { version = "1.37.0", default-features = false }

crates/rattler_networking/Cargo.toml

@@ -47,3 +47,4 @@ tokio = { workspace = true, features = ["macros"] }
 axum = { workspace = true }
 reqwest-retry = { workspace = true }
 sha2 = { workspace = true }
+temp-env = { workspace = true }

crates/rattler_networking/src/authentication_middleware.rs

@@ -399,4 +399,33 @@ mod tests {
 
         Ok(())
     }
+
+    #[test]
+    fn test_rattler_auth_file_env_var_handling() -> anyhow::Result<()> {
+        let tdir = tempdir()?;
+
+        let storage = temp_env::with_var(
+            "RATTLER_AUTH_FILE",
+            Some(
+                tdir.path()
+                    .to_path_buf()
+                    .join("auth.json")
+                    .to_str()
+                    .unwrap(),
+            ),
+            || AuthenticationStorage::from_env().unwrap(),
+        );
+
+        let host = "test.example.com";
+        let authentication = Authentication::CondaToken("testtoken".to_string());
+        storage.store(host, &authentication)?;
+
+        let file = tdir.path().join("auth.json");
+        assert_eq!(
+            std::fs::read_to_string(file)?,
+            "{\"test.example.com\":{\"CondaToken\":\"testtoken\"}}"
+        );
+
+        Ok(())
+    }
 }

crates/rattler_networking/src/authentication_storage/storage.rs

@@ -51,6 +51,35 @@ impl AuthenticationStorage {
         }
     }
 
+    /// Create a new authentication storage with the default backends
+    /// respecting the `RATTLER_AUTH_FILE` environment variable.
+    /// If the variable is set, the file storage backend will be used
+    /// with the path specified in the variable
+    pub fn from_env() -> Result<Self> {
+        if let Ok(auth_file) = std::env::var("RATTLER_AUTH_FILE") {
+            let mut storage = Self::new();
+            let path = std::path::Path::new(&auth_file);
+
+            tracing::info!(
+                "\"RATTLER_AUTH_FILE\" environment variable set, using file storage at {}",
+                auth_file
+            );
+
+            let backend = FileStorage::new(path.to_path_buf()).map_err(|e| {
+                anyhow!(
+                    "Error creating file storage backend for RATTLER_AUTH_FILE ({}): {}",
+                    auth_file,
+                    e
+                )
+            })?;
+
+            storage.add_backend(Arc::from(backend));
+            Ok(storage)
+        } else {
+            Ok(Self::default())
+        }
+    }
+
     /// Add a new storage backend to the authentication storage
     /// (backends are tried in the order they are added)
     pub fn add_backend(&mut self, backend: Arc<dyn StorageBackend + Send + Sync>) {