Improve error messaging for auth scheme selection (#3277) (85d2621b) · Commits · Public Repositories / Smithy Rust

CHANGELOG.next.toml

+12 −0

Original line number	Diff line number	Diff line
		@@ -49,3 +49,15 @@ This is designed for unit tests and using local mocks like DynamoDB Local and Lo
		meta = { "breaking" = false, "tada" = true, "bug" = false }
		author = "rcoh"
		references = ["smithy-rs#3279", "aws-sdk-rust#971"]

		[[aws-sdk-rust]]
		message = "Improve the error messages for when auth fails to select an auth scheme for a request."
		references = ["aws-sdk-rust#979", "smithy-rs#3277"]
		meta = { "breaking" = false, "tada" = false, "bug" = false }
		author = "jdisanti"

		[[smithy-rs]]
		message = "Improve the error messages for when auth fails to select an auth scheme for a request."
		references = ["smithy-rs#3277"]
		meta = { "breaking" = false, "tada" = false, "bug" = false, "target" = "client" }
		author = "jdisanti"

aws/sdk/integration-tests/dynamodb/tests/auth_scheme_error.rs

0 → 100644

+32 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
		* SPDX-License-Identifier: Apache-2.0
		*/

		use aws_sdk_dynamodb::config::Region;
		use aws_sdk_dynamodb::error::DisplayErrorContext;
		use aws_sdk_dynamodb::{Client, Config};
		use aws_smithy_runtime::assert_str_contains;
		use aws_smithy_runtime::client::http::test_util::capture_request;

		#[tokio::test]
		async fn auth_scheme_error() {
		let (http_client, _) = capture_request(None);
		let config = Config::builder()
		.behavior_version_latest()
		.http_client(http_client)
		.region(Region::new("us-west-2"))
		// intentionally omitting credentials_provider
		.build();
		let client = Client::from_conf(config);

		let err = client
		.list_tables()
		.send()
		.await
		.expect_err("there is no credential provider, so this must fail");
		assert_str_contains!(
		DisplayErrorContext(&err).to_string(),
		"\"sigv4\" wasn't a valid option because there was no identity resolver for it. Be sure to set an identity"
		);
		}

rust-runtime/aws-smithy-runtime/src/client/orchestrator/auth.rs

+220 −7

Original line number	Diff line number	Diff line
		@@ -20,18 +20,86 @@ use std::error::Error as StdError;
		use std::fmt;
		use tracing::trace;

		#[derive(Debug)]
		struct NoMatchingAuthSchemeError(ExploredList);

		impl fmt::Display for NoMatchingAuthSchemeError {
		fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		let explored = &self.0;

		// Use the information we have about the auth options that were explored to construct
		// as helpful of an error message as possible.
		if explored.items().count() == 0 {
		return f.write_str(
		"no auth options are available. This can happen if there's \
		a problem with the service model, or if there is a codegen bug.",
		);
		}
		if explored
		.items()
		.all(\|explored\| matches!(explored.result, ExploreResult::NoAuthScheme))
		{
		return f.write_str(
		"no auth schemes are registered. This can happen if there's \
		a problem with the service model, or if there is a codegen bug.",
		);
		}

		let mut try_add_identity = false;
		let mut likely_bug = false;
		f.write_str("failed to select an auth scheme to sign the request with.")?;
		for item in explored.items() {
		write!(
		f,
		" \"{}\" wasn't a valid option because ",
		item.scheme_id.as_str()
		)?;
		f.write_str(match item.result {
		ExploreResult::NoAuthScheme => {
		likely_bug = true;
		"no auth scheme was registered for it."
		}
		ExploreResult::NoIdentityResolver => {
		try_add_identity = true;
		"there was no identity resolver for it."
		}
		ExploreResult::MissingEndpointConfig => {
		likely_bug = true;
		"there is auth config in the endpoint config, but this scheme wasn't listed in it \
		(see https://github.com/smithy-lang/smithy-rs/discussions/3281 for more details)."
		}
		ExploreResult::NotExplored => {
		debug_assert!(false, "this should be unreachable");
		"<unknown>"
		}
		})?;
		}
		if try_add_identity {
		f.write_str(" Be sure to set an identity, such as credentials, auth token, or other identity type that is required for this service.")?;
		} else if likely_bug {
		f.write_str(" This is likely a bug.")?;
		}
		if explored.truncated {
		f.write_str(" Note: there were other auth schemes that were evaluated that weren't listed here.")?;
		}

		Ok(())
		}
		}

		impl StdError for NoMatchingAuthSchemeError {}

		#[derive(Debug)]
		enum AuthOrchestrationError {
		NoMatchingAuthScheme,
		MissingEndpointConfig,
		BadAuthSchemeEndpointConfig(Cow<'static, str>),
		}

		impl fmt::Display for AuthOrchestrationError {
		fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		match self {
		Self::NoMatchingAuthScheme => f.write_str(
		"no auth scheme matched auth scheme options. This is a bug. Please file an issue.",
		),
		// This error is never bubbled up
		Self::MissingEndpointConfig => f.write_str("missing endpoint config"),
		Self::BadAuthSchemeEndpointConfig(message) => f.write_str(message),
		}
		}
		@@ -59,6 +127,8 @@ pub(super) async fn orchestrate_auth(
		"orchestrating auth",
		);

		let mut explored = ExploredList::default();

		// Iterate over IDs of possibly-supported auth schemes
		for &scheme_id in options.as_ref() {
		// For each ID, try to resolve the corresponding auth scheme.
		@@ -95,16 +165,21 @@ pub(super) async fn orchestrate_auth(
		)?;
		return Ok(());
		}
		Err(AuthOrchestrationError::NoMatchingAuthScheme) => {
		Err(AuthOrchestrationError::MissingEndpointConfig) => {
		explored.push(scheme_id, ExploreResult::MissingEndpointConfig);
		continue;
		}
		Err(other_err) => return Err(other_err.into()),
		}
		} else {
		explored.push(scheme_id, ExploreResult::NoIdentityResolver);
		}
		} else {
		explored.push(scheme_id, ExploreResult::NoAuthScheme);
		}
		}

		Err(AuthOrchestrationError::NoMatchingAuthScheme.into())
		Err(NoMatchingAuthSchemeError(explored).into())
		}

		fn extract_endpoint_auth_scheme_config(
		@@ -135,10 +210,66 @@ fn extract_endpoint_auth_scheme_config(
		.and_then(Document::as_string);
		config_scheme_id == Some(scheme_id.as_str())
		})
		.ok_or(AuthOrchestrationError::NoMatchingAuthScheme)?;
		.ok_or(AuthOrchestrationError::MissingEndpointConfig)?;
		Ok(AuthSchemeEndpointConfig::from(Some(auth_scheme_config)))
		}

		#[derive(Debug)]
		enum ExploreResult {
		NotExplored,
		NoAuthScheme,
		NoIdentityResolver,
		MissingEndpointConfig,
		}

		/// Information about an evaluated auth option.
		/// This should be kept small so it can fit in an array on the stack.
		#[derive(Debug)]
		struct ExploredAuthOption {
		scheme_id: AuthSchemeId,
		result: ExploreResult,
		}
		impl Default for ExploredAuthOption {
		fn default() -> Self {
		Self {
		scheme_id: AuthSchemeId::new(""),
		result: ExploreResult::NotExplored,
		}
		}
		}

		const MAX_EXPLORED_LIST_LEN: usize = 8;

		/// Stack allocated list of explored auth options for error messaging
		#[derive(Default)]
		struct ExploredList {
		items: [ExploredAuthOption; MAX_EXPLORED_LIST_LEN],
		len: usize,
		truncated: bool,
		}
		impl ExploredList {
		fn items(&self) -> impl Iterator<Item = &ExploredAuthOption> {
		self.items.iter().take(self.len)
		}

		fn push(&mut self, scheme_id: AuthSchemeId, result: ExploreResult) {
		if self.len + 1 >= self.items.len() {
		self.truncated = true;
		} else {
		self.items[self.len] = ExploredAuthOption { scheme_id, result };
		self.len += 1;
		}
		}
		}
		impl fmt::Debug for ExploredList {
		fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		f.debug_struct("ExploredList")
		.field("items", &&self.items[0..self.len])
		.field("truncated", &self.truncated)
		.finish()
		}
		}

		#[cfg(all(test, feature = "test-util"))]
		mod tests {
		use super::*;
		@@ -481,4 +612,86 @@ mod tests {
		.unwrap()
		);
		}

		#[test]
		fn friendly_error_messages() {
		let err = NoMatchingAuthSchemeError(ExploredList::default());
		assert_eq!(
		"no auth options are available. This can happen if there's a problem with \
		the service model, or if there is a codegen bug.",
		err.to_string()
		);

		let mut list = ExploredList::default();
		list.push(
		AuthSchemeId::new("SigV4"),
		ExploreResult::NoIdentityResolver,
		);
		list.push(
		AuthSchemeId::new("SigV4a"),
		ExploreResult::NoIdentityResolver,
		);
		let err = NoMatchingAuthSchemeError(list);
		assert_eq!(
		"failed to select an auth scheme to sign the request with. \
		\"SigV4\" wasn't a valid option because there was no identity resolver for it. \
		\"SigV4a\" wasn't a valid option because there was no identity resolver for it. \
		Be sure to set an identity, such as credentials, auth token, or other identity \
		type that is required for this service.",
		err.to_string()
		);

		// It should prioritize the suggestion to try an identity before saying it's a bug
		let mut list = ExploredList::default();
		list.push(
		AuthSchemeId::new("SigV4"),
		ExploreResult::NoIdentityResolver,
		);
		list.push(
		AuthSchemeId::new("SigV4a"),
		ExploreResult::MissingEndpointConfig,
		);
		let err = NoMatchingAuthSchemeError(list);
		assert_eq!(
		"failed to select an auth scheme to sign the request with. \
		\"SigV4\" wasn't a valid option because there was no identity resolver for it. \
		\"SigV4a\" wasn't a valid option because there is auth config in the endpoint \
		config, but this scheme wasn't listed in it (see \
		https://github.com/smithy-lang/smithy-rs/discussions/3281 for more details). \
		Be sure to set an identity, such as credentials, auth token, or other identity \
		type that is required for this service.",
		err.to_string()
		);

		// Otherwise, it should suggest it's a bug
		let mut list = ExploredList::default();
		list.push(
		AuthSchemeId::new("SigV4a"),
		ExploreResult::MissingEndpointConfig,
		);
		let err = NoMatchingAuthSchemeError(list);
		assert_eq!(
		"failed to select an auth scheme to sign the request with. \
		\"SigV4a\" wasn't a valid option because there is auth config in the endpoint \
		config, but this scheme wasn't listed in it (see \
		https://github.com/smithy-lang/smithy-rs/discussions/3281 for more details). \
		This is likely a bug.",
		err.to_string()
		);

		// Truncation should be indicated
		let mut list = ExploredList::default();
		for _ in 0..=MAX_EXPLORED_LIST_LEN {
		list.push(
		AuthSchemeId::new("dontcare"),
		ExploreResult::MissingEndpointConfig,
		);
		}
		let err = NoMatchingAuthSchemeError(list).to_string();
		if !err.contains(
		"Note: there were other auth schemes that were evaluated that weren't listed here",
		) {
		panic!("The error should indicate that the explored list was truncated.");
		}
		}
		}

rust-runtime/aws-smithy-runtime/src/test_util.rs

+2 −0

Original line number	Diff line number	Diff line
		@@ -5,3 +5,5 @@

		/// Utility for capturing and displaying logs during a unit test.
		pub mod capture_test_logs;

		mod assertions;

rust-runtime/aws-smithy-runtime/src/test_util/assertions.rs

0 → 100644

+57 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
		* SPDX-License-Identifier: Apache-2.0
		*/

		/// Asserts that a given string value `$str` contains a substring `$expected`.
		///
		/// This macro can also take a custom panic message with formatting.
		#[macro_export]
		macro_rules! assert_str_contains {
		($str:expr, $expected:expr) => {
		assert_str_contains!($str, $expected, "")
		};
		($str:expr, $expected:expr, $($fmt_args:tt)+) => {{
		let s = $str;
		let expected = $expected;
		if !s.contains(&expected) {
		panic!(
		"assertion failed: `str.contains(expected)`\n{:>8}: {expected}\n{:>8}: {s}\n{}",
		"expected",
		"str",
		::std::fmt::format(::std::format_args!($($fmt_args)+)),
		);
		}
		}};
		}

		#[cfg(test)]
		mod tests {
		use std::panic::{catch_unwind, UnwindSafe};

		fn expect_panic(f: impl FnOnce() -> () + UnwindSafe) -> String {
		*catch_unwind(f)
		.expect_err("it should fail")
		.downcast::<String>()
		.expect("it should be a string")
		}

		#[test]
		fn assert_str_contains() {
		assert_str_contains!("foobar", "bar");
		assert_str_contains!("foobar", "o");

		assert_eq!(
		"assertion failed: `str.contains(expected)`\nexpected: not-in-it\n str: foobar\n",
		expect_panic(\|\| assert_str_contains!("foobar", "not-in-it"))
		);
		assert_eq!(
		"assertion failed: `str.contains(expected)`\nexpected: not-in-it\n str: foobar\nsome custom message",
		expect_panic(\|\| assert_str_contains!("foobar", "not-in-it", "some custom message"))
		);
		assert_eq!(
		"assertion failed: `str.contains(expected)`\nexpected: not-in-it\n str: foobar\nsome custom message with formatting",
		expect_panic(\|\| assert_str_contains!("foobar", "not-in-it", "some custom message with {}", "formatting"))
		);
		}
		}