log adapter for DLT

This crate is a log adapter for integrating with the Diagnostic Log and Trace (DLT) system.

It provides functionality to register applications and contexts with the DLT daemon and implements a logger that sends log messages to the DLT system. The library is designed to be used with the standard log crate, which provides a flexible logging API for Rust applications.

The DLT system is a flexible and scalable logging framework that is widely used in the automotive industry for logging and tracing in embedded systems. It provides features such as log level filtering, message formatting, and log message buffering. For more information about DLT, see the DLT project on GitHub.

Documentation

Module documentation can be found at docs.rs.

System dependencies

You need to have libclang-dev installed on your system to run the binding generation and libdlt-dev to link against the DLT library. On Ubuntu, you can install that with the following command:

sudo apt-get install libclang-dev libdlt-dev

The integration with the DLT system is achieved through the underlying C library for DLT. bindgen is used to generate the FFI (Foreign Function Interface) bindings. The bindings are generated during the build process in order to ensure that the Rust code remains in sync with the system’s DLT library.

Example usage

Add the dlt_log crate to your Cargo.toml:

[dependencies]
log = { version = "0.4", features = ["std"] }
dlt_log = "0.1"

To use this library, you need to initialize it with your application and context information. This will register your application and context with the DLT daemon and set up the logger.

fn main() {
    let _ = dlt_log::init("TEST", "Rust tests", "EXPL", "Smoke test example");

    log::trace!("Tracing the untraceable!");
    log::debug!("Debugging the debugger!");
    log::info!("Information overload: {} + {} = {}", 2, 2, 4);
    log::warn!("Warning: Low on coffee!");
    log::error!("Error: Something went terribly right!");
}

Connect the DLT viewer to the DLT daemon to view the log messages. The default log level is set to info, so only log messages with a level of info or higher will be displayed. See the Log levels section for more information on how to configure the log levels.

Example for cross-compilation

As an example for cross-compilation, assume a yocto SDK is installed at /opt/poky/5.1.2 for aarch64 architecture that includes the DLT library:

• /opt/poky/5.1.2/environment-setup-cortexa57-poky-linux
• /opt/poky/5.1.2/sysroots/cortexa57-poky-linux/usr/lib/libdlt.so
• /opt/poky/5.1.2/sysroots/cortexa57-poky-linux/usr/include/dlt/dlt.h

Create .cargo/config.toml in your project directory with the following content:

[target.aarch64-unknown-linux-gnu]
linker="/opt/poky/5.1.2/sysroots/x86_64-pokysdk-linux/usr/bin/aarch64-poky-linux/aarch64-poky-linux-gcc"
rustflags = [
"-C", "link-arg=--sysroot=/opt/poky/5.1.2/sysroots/cortexa57-poky-linux",
]

Bindgen needs to know the sysroot path to find the DLT headers, so set the BINDGEN_EXTRA_CLANG_ARGS environment variable before building the project:

export BINDGEN_EXTRA_CLANG_ARGS="--sysroot=/opt/poky/5.1.2/sysroots/cortexa57-poky-linux"
cargo build --release --target aarch64-unknown-linux-gnu

Log levels

The log levels and logging backend are configured by the DLT system. For configuration, follow the DLT documentation.

For example, to enable all log levels, set the DLT_INITIAL_LOG_LEVEL environment variable to ::6.

DLT_INITIAL_LOG_LEVEL="::6" cargo run --example simple

Logging to console

By default, the log messages are sent to the DLT daemon. To view the logs, you can use the DLT viewer tool provided by the DLT daemon. The logs can also be redirected to the console by setting the DLT_LOCAL_PRINT_MODE environment variable to FORCE_ON.

DLT_LOCAL_PRINT_MODE=FORCE_ON DLT_INITIAL_LOG_LEVEL="::6" cargo run --example simple

The output will look like this:

2025/01/21 19:12:22.090974   28995094 000 ECU1 TEST EXPL log verbose V 1 [Tracing the untraceable!]
2025/01/21 19:12:22.091176   28995096 001 ECU1 TEST EXPL log debug V 1 [Debugging the debugger!]
2025/01/21 19:12:22.091248   28995097 002 ECU1 TEST EXPL log info V 1 [Information overload: 2 + 2 = 4]
2025/01/21 19:12:22.091284   28995097 003 ECU1 TEST EXPL log warn V 1 [Warning: Low on coffee!]
2025/01/21 19:12:22.091336   28995097 004 ECU1 TEST EXPL log error V 1 [Error: Something went terribly right!]

License

This project is licensed under the MIT License - see the LICENSE file for details.

License information for DLT daemon and library can be found at Diagnostic Log and Trace.