Add an Option to disable retries (#694)

include/aws/io/retry_strategy.h

@@ -106,13 +106,13 @@ enum aws_exponential_backoff_jitter_mode {
  * "use defaults"
  */
 struct aws_exponential_backoff_retry_options {
-    /** Event loop group to use for scheduling tasks. */
+    /* Event loop group to use for scheduling tasks. */
     struct aws_event_loop_group *el_group;
-    /** Max retries to allow. The default value is 10 */
+    /* Max retries to allow. The default value is 10 */
     size_t max_retries;
-    /** Scaling factor to add for the backoff. Default is 500ms */
+    /* Scaling factor to add for the backoff. Default is 500ms */
     uint32_t backoff_scale_factor_ms;
-    /** Max retry backoff in seconds. Default is 20 seconds */
+    /* Max retry backoff in seconds. Default is 20 seconds */
     uint32_t max_backoff_secs;
     /** Jitter mode to use, see comments for aws_exponential_backoff_jitter_mode.
      * Default is AWS_EXPONENTIAL_BACKOFF_JITTER_DEFAULT */
@@ -139,6 +139,14 @@ struct aws_exponential_backoff_retry_options {
     const struct aws_shutdown_callback_options *shutdown_options;
 };
 
+struct aws_no_retry_options {
+    /**
+     * Optional shutdown callback that gets invoked, with appropriate user data,
+     * when the resources used by the retry_strategy are no longer in use.
+     */
+    const struct aws_shutdown_callback_options *shutdown_options;
+};
+
 struct aws_standard_retry_options {
     struct aws_exponential_backoff_retry_options backoff_retry_options;
     /** capacity for partitions. Defaults to 500 */
@@ -235,6 +243,16 @@ AWS_IO_API struct aws_retry_strategy *aws_retry_strategy_new_standard(
     struct aws_allocator *allocator,
     const struct aws_standard_retry_options *config);
 
+/**
+ * This retry strategy is used to disable retries. Passed config can be null.
+ * Calling `aws_retry_strategy_acquire_retry_token` will raise error `AWS_IO_RETRY_PERMISSION_DENIED`.
+ * Calling any function apart from the `aws_retry_strategy_acquire_retry_token` and `aws_retry_strategy_release` will
+ * result in a fatal error.
+ */
+AWS_IO_API struct aws_retry_strategy *aws_retry_strategy_new_no_retry(
+    struct aws_allocator *allocator,
+    const struct aws_no_retry_options *config);
+
 AWS_EXTERN_C_END
 AWS_POP_SANE_WARNING_LEVEL
 

source/no_retry_strategy.c

@@ -0,0 +1,85 @@
+/**
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0.
+ */
+#include <aws/common/ref_count.h>
+#include <aws/io/io.h>
+#include <aws/io/retry_strategy.h>
+
+struct aws_retry_strategy_no_retries {
+    struct aws_retry_strategy base;
+    struct aws_shutdown_callback_options shutdown_options;
+};
+
+static void s_no_retry_destroy(struct aws_retry_strategy *retry_strategy) {
+    if (retry_strategy) {
+        struct aws_retry_strategy_no_retries *strategy = retry_strategy->impl;
+        aws_simple_completion_callback *completion_callback = strategy->shutdown_options.shutdown_callback_fn;
+        void *completion_user_data = strategy->shutdown_options.shutdown_callback_user_data;
+
+        aws_mem_release(retry_strategy->allocator, strategy);
+        if (completion_callback != NULL) {
+            completion_callback(completion_user_data);
+        }
+    }
+}
+
+static int s_no_retry_acquire_token(
+    struct aws_retry_strategy *retry_strategy,
+    const struct aws_byte_cursor *partition_id,
+    aws_retry_strategy_on_retry_token_acquired_fn *on_acquired,
+    void *user_data,
+    uint64_t timeout_ms) {
+    (void)retry_strategy;
+    (void)partition_id;
+    (void)on_acquired;
+    (void)user_data;
+    (void)timeout_ms;
+    return aws_raise_error(AWS_IO_RETRY_PERMISSION_DENIED);
+}
+
+static int s_no_retry_schedule_retry(
+    struct aws_retry_token *token,
+    enum aws_retry_error_type error_type,
+    aws_retry_strategy_on_retry_ready_fn *retry_ready,
+    void *user_data) {
+    (void)token;
+    (void)error_type;
+    (void)retry_ready;
+    (void)user_data;
+    AWS_FATAL_ASSERT(0 && "schedule_retry must not be called for no_retries retry strategy");
+}
+
+static int s_no_retry_record_success(struct aws_retry_token *token) {
+    (void)token;
+    AWS_FATAL_ASSERT(0 && "record_success must not be called for no_retries retry strategy");
+}
+
+static void s_no_retry_release_token(struct aws_retry_token *token) {
+    (void)token;
+    AWS_FATAL_ASSERT(0 && "release_token must not be called for no_retries retry strategy");
+}
+
+static struct aws_retry_strategy_vtable s_exponential_retry_vtable = {
+    .destroy = s_no_retry_destroy,
+    .acquire_token = s_no_retry_acquire_token,
+    .schedule_retry = s_no_retry_schedule_retry,
+    .record_success = s_no_retry_record_success,
+    .release_token = s_no_retry_release_token,
+};
+
+struct aws_retry_strategy *aws_retry_strategy_new_no_retry(
+    struct aws_allocator *allocator,
+    const struct aws_no_retry_options *config) {
+    struct aws_retry_strategy_no_retries *strategy =
+        aws_mem_calloc(allocator, 1, sizeof(struct aws_retry_strategy_no_retries));
+    strategy->base.allocator = allocator;
+    strategy->base.impl = strategy;
+    strategy->base.vtable = &s_exponential_retry_vtable;
+    aws_atomic_init_int(&strategy->base.ref_count, 1);
+
+    if (config != NULL && config->shutdown_options) {
+        strategy->shutdown_options = *config->shutdown_options;
+    }
+    return &strategy->base;
+}

tests/CMakeLists.txt

@@ -316,6 +316,7 @@ add_test_case(test_exponential_backoff_retry_client_errors_do_not_count)
 add_test_case(test_exponential_backoff_retry_no_jitter_time_taken)
 add_test_case(test_exponential_max_backoff_retry_no_jitter)
 add_test_case(test_exponential_backoff_retry_invalid_options)
+add_test_case(test_no_retries)
 
 add_test_case(test_standard_retry_strategy_setup_shutdown)
 add_test_case(test_standard_retry_strategy_failure_exhausts_bucket)

tests/no_retry_strategy_test.c

@@ -0,0 +1,27 @@
+/**
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0.
+ */
+#include <aws/io/io.h>
+#include <aws/io/retry_strategy.h>
+#include <aws/testing/aws_test_harness.h>
+
+static int s_test_no_retries_fn(struct aws_allocator *allocator, void *ctx) {
+    (void)ctx;
+
+    aws_io_library_init(allocator);
+
+    struct aws_retry_strategy *retry_strategy = aws_retry_strategy_new_no_retry(allocator, NULL);
+    ASSERT_NOT_NULL(retry_strategy);
+
+    ASSERT_ERROR(
+        AWS_IO_RETRY_PERMISSION_DENIED, aws_retry_strategy_acquire_retry_token(retry_strategy, NULL, NULL, NULL, 0));
+
+    aws_retry_strategy_release(retry_strategy);
+
+    aws_io_library_clean_up();
+
+    return AWS_OP_SUCCESS;
+}
+
+AWS_TEST_CASE(test_no_retries, s_test_no_retries_fn)