Crate sentry

Expand description

This crate provides support for logging events and errors / panics to the Sentry error logging service. It integrates with the standard panic system in Rust as well as a few popular error handling setups.

Quickstart

To use the crate you need to create a client first. When a client is created it’s typically bound to the current thread by calling bind_client. By default this happens by using the sentry::init convenience function. When the client is bound to the main thread it also becomes the default client for future threads created but it is always possible to override the client for a thread later by explicitly binding it.

The sentry::init function returns a guard that when dropped will flush Events that were not yet sent to the sentry service. It has a two second deadline for this so shutdown of applications might slightly delay as a result of this. Keep the guard around or sending events will not work.

extern crate sentry;

fn main() {
    let _guard = sentry::init("https://key@sentry.io/42");
    sentry::capture_message("Hello World!", sentry::Level::Info);
    // when the guard goes out of scope here, the client will wait up to two
    // seconds to send remaining events to the service.
}

Integrations

What makes this crate useful are the various integrations that exist. Some of them are enabled by default, some uncommon ones or for deprecated parts of the ecosystem a feature flag needs to be enabled. For the available integrations and how to use them see integrations.

Scopes, Threads and Hubs

Data is typically bound to a Scope. Scopes are stored in a hidden stack on a Hub. Once the library has been initialized a hub is automatically available. In the default config a new hub is created for each thread and they act independently.

The thread that calls sentry::init initializes the first hub which then automatically becomes the base of new hubs (You can get that hub by calling Hub::main()). If a new thread is spawned it gets a new hub based on that one (the thread calls Hub::new_from_top(Hub::main())). The current thread’s hub is returned from Hub::current(). Any hub that is wrapped in an Arc can be temporarily bound to a thread with Hub::run. For more information see Hub.

Users are expected to reconfigure the scope with configure_scope. For more elaborate scope management the hub needs to be interfaced with directly.

In some situations (particularly in async code) it’s often not possible to use the thread local hub. In that case a hub can be explicitly created and passed around. However due to the nature of some integrations some functionality like automatic breadcrumb recording depends on the thread local hub being correctly configured.

Minimal API

This crate can also be used in “minimal” mode. This is enabled by disabling all default features of the crate. In that mode a minimal API set is retained that can be used to instrument code for Sentry without actually using Sentry. The minimal API is a small set of APIs that dispatch to the underlying implementations on the configured Sentry client. If the client is not there the minimal API will blackhole a lot of operations.

Only if a user then also uses and configures Sentry this code becomes used.

In minimal mode some types are restricted in functionality. For instance the Client is not available and the Hub does not retain all API functionality. To see what the APIs in mnimal mode look like you can build the docs for this crate without any features enabled.

Features

Functionality of the crate can be turned on and off by feature flags. This is the current list of feature flags:

default flags:

with_client_implementation: turns on the real client implementation.
with_default_transport: compiles in the default HTTP transport.
with_backtrace: enables backtrace support (automatically turned on in a few cases)
with_panic: enables the panic integration
with_failure: enables the failure integration
with_log: enables the log integration
with_env_logger: enables the env_logger integration
with_device_info: enables the device info context
with_rust_info: enables the rust compiler info context
with_debug_meta: enables debug meta support (permits server side symbolication)
with_debug_to_log: when enabled sentry will debug log to a debug log at all times instead of printing to stderr when debug is enabled on the hub.

additional features:

with_error_chain: enables the error-chain integration
with_test_support: enables the test support module
with_reqwest_transport: enables the reqwest transport explicitly. This is currently the default transport.
with_curl_transport: enables the curl transport.