add create_empty_credential

sdk/identity/src/token_credentials/empty_credential.rs

@@ -0,0 +1,25 @@
+use azure_core::auth::{AccessToken, Secret, TokenCredential};
+use std::{str, sync::Arc};
+use time::{Duration, OffsetDateTime};
+
+#[derive(Debug, Default)]
+pub struct EmptyCredential {}
+
+#[cfg_attr(target_arch = "wasm32", async_trait::async_trait(?Send))]
+#[cfg_attr(not(target_arch = "wasm32"), async_trait::async_trait)]
+impl TokenCredential for EmptyCredential {
+    /// Returns an empty string as the token.
+    async fn get_token(&self, _scopes: &[&str]) -> azure_core::Result<AccessToken> {
+        Ok(AccessToken::new(
+            Secret::new(String::new()),
+            OffsetDateTime::now_utc() + Duration::hours(1),
+        ))
+    }
+    async fn clear_cache(&self) -> azure_core::Result<()> {
+        Ok(())
+    }
+}
+
+pub fn create_empty_credential() -> Arc<dyn TokenCredential> {
+    Arc::new(EmptyCredential::default())
+}

sdk/identity/src/token_credentials/mod.rs

@@ -15,6 +15,7 @@ mod cache;
 mod client_certificate_credentials;
 mod client_secret_credentials;
 mod default_credentials;
+mod empty_credential;
 mod environment_credentials;
 mod imds_managed_identity_credentials;
 mod workload_identity_credentials;
@@ -28,6 +29,7 @@ pub use azureauth_cli_credentials::*;
 pub use client_certificate_credentials::*;
 pub use client_secret_credentials::*;
 pub use default_credentials::*;
+pub use empty_credential::*;
 pub use environment_credentials::*;
 pub use imds_managed_identity_credentials::*;
 pub use workload_identity_credentials::*;