Tarpaulin is designed to be a code coverage reporting tool for the Cargo build system, named for a waterproof cloth used to cover cargo on a ship. Currently, tarpaulin provides working line coverage but is still in the early development stage and therefore may contain some bugs. A lot of work has been done to get it working on some example projects and smaller crates so please report anything you find that's wrong. Also, check out our roadmap for planned features.
Tarpaulin only supports x86_64 processors running Linux. This is because instrumenting breakpoints into executables and tracing their execution requires processor and OS specific code. It is a goal when greater stability is reached to add wider system support, however this is sufficient to run Tarpaulin on popular CI tools like Travis.
It can also be run in Docker, which is useful for when you don't use Linux but want to run it locally, e.g. during development. See below for how to do that.
Below is a list of features currently implemented. As Tarpaulin loads binary files into memory and parses the debugging information, different setups could lead to coverage not working. In this instance, please raise an issue detailing your setup and an example project and I'll attempt to fix it (please link us to a repo and the commit containing your project and paste the verbose output).
Tarpaulin depends on cargo which depends on SSL. Make sure you've installed your distros SSL development libraries and they are on your path before attempting to install tarpaulin. For example for Debian/Ubuntu:
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apt-get update && apt-get install libssl-dev pkg-config cmake zlib1g-dev
Tarpaulin is a command-line program, you install it into your linux development environment with cargo install:
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cargo install cargo-tarpaulin
If you use nested use statements you need the latest develop build of tarpaulin as syntex\_syntax dependency can't handle them. To install tarpaulin via cargo with this you need the following command RUSTFLAGS="--cfg procmacro2_semver_exempt" cargo install cargo-tarpaulin --git https://github.com/xd009642/tarpaulin --branch develop or you can use the docker develop image.
To get detailed help on available arguments when running tarpaulin call:
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cargo tarpaulin --help
Currently no options are required, if no root directory is defined Tarpaulin
will run in the current working directory.
Below is a Tarpaulin run utilising one of our example projects. This is a relatively simple project to test and if you check the test, you can see the output correctly reports the lines the test hits.
```text cargo tarpaulin -v Running Tarpaulin Finished dev [unoptimized + debuginfo] target(s) in 0.0 secs Processing simple_project Launching test
running 1 test test tests::bad_test ... ok
test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured
Coverage Results src/unused.rs:4 - hits: 0 src/unused.rs:5 - hits: 0 src/unused.rs:6 - hits: 0 src/unused.rs:7 - hits: 0 src/lib.rs:4 - hits: 1 src/lib.rs:5 - hits: 1 src/lib.rs:6 - hits: 0 src/lib.rs:8 - hits: 1 src/lib.rs:10 - hits: 1 src/lib.rs:21 - hits: 1 src/lib.rs:22 - hits: 1 src/lib.rs:23 - hits: 1
src/lib.rs: 7/8 src/unused.rs: 0/4
58.33% coverage, 7/12 lines covered Tarpaulin finished ```
Hint: if using coveralls.io with travis-ci run with the options "--ciserver travis-ci --coveralls $TRAVISJOBID". The coveralls.io repo-token is mainly designed for private repos and it won't generate a badge for the coverage results submitted (although you can still see them on the coveralls web interface). For an example of a project using Tarpaulin, you can check out my crate keygraph-rs.
The expected most common usecase is launching coverage via a CI service to upload to a site like codecov or coveralls. Given the built in support and ubiquity of travis-ci it seems prudent to document the required steps here for new users. To follow these steps you'll first need a travis-ci and a project setup for your coverage reporting site of choice.
We recommend taking the minimal rust .travis.yml, installing the libssl-dev dependency tarpaulin has and then running Tarpaulin with the version of rustc you require.
The travis-install shell script will install the latest tagged release built
on travis to your travis instance and significantly speeds up the travis
builds. If you want an earlier version of tarpaulin, look at the script to
see what you need to implement and adjust accordingly or use
cargo install cargo-tarpaulin and specify the version in the arguments.
For codecov.io you'll need to export CODECOV_TOKEN are instructions on this in the settings of your codecov project.
```yml language: rust sudo: required dist: trusty addons: apt: packages: - libssl-dev cache: cargo rust: - stable - beta - nightly matrix: allow_failures: - rust: nightly script: - cargo clean - cargo build - cargo test
aftersuccess: | if [[ "$TRAVISRUSTVERSION" == stable ]]; then bash <(curl https://raw.githubusercontent.com/xd009642/tarpaulin/master/travis-install.sh) # Uncomment the following line for coveralls.io # cargo tarpaulin --ciserver travis-ci --coveralls $TRAVISJOB_ID
# Uncomment the following two lines create and upload a report for codecov.io
# cargo tarpaulin --out Xml
# bash <(curl -s https://codecov.io/bash)
fi ```
Tarpaulin has builds deployed to docker-hub, to run Tarpaulin on any system that has Docker, run this in your project directory:
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docker run --security-opt seccomp=unconfined -v "$PWD:/volume" xd009642/tarpaulin
This builds your project inside Docker and runs Tarpaulin without any arguments. There are also tags available for the latest version on the develop branch in stable or nightly. And versions after 0.5.6 will have the latest release built with the rust stable and nightly compilers. To get the latest development version built with rustc-nightly run the following:
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docker run --security-opt seccomp=unconfined -v "$PWD:/volume" xd009642/tarpaulin:develop-nightly
Note that the build might fail if the Docker image doesn't contain any necessary dependencies. In that case, you can install dependencies before, like this:
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docker run --security-opt seccomp=unconfined -v "$PWD:/volume" xd009642/tarpaulin sh -c "apt-get install xxx && cargo tarpaulin"
If you want to have an HTML report with the results, first generate XML:
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docker run --security-opt seccomp=unconfined -v "$PWD:/volume" xd009642/tarpaulin cargo tarpaulin --out Xml
You'll get a cobertura.xml file in your directory. To turn that into an HTML
report, you can use pycobertura:
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pip install pycobertura
pycobertura show --format html --output coverage.html cobertura.xml
Then open coverage.html in your browser.
Normally, Tarpaulin can't report on code coverage within the code for a procedural macro. You'll need to add a test that expands the macro at run time in order to get those stats. The runtime-macros crate was made for this purpose, and its documentation describes how to use it with Tarpaulin.
Issues, feature requests and pull requests are always welcome! For a guide on how to approach bugs found in Tarpaulin and adding features please check CONTRIBUTING.
Rust 1.23 introduced a regression in the compiler affecting tarpaulin's accuracy. If you see missing lines or files, check your compiler version.
Tarpaulin is currently licensed under the terms of both the MIT license and the Apache License (Version 2.0). See LICENSE-MIT and LICENSE-APACHE for more details.
I wouldn't have been able to make progress as quickly in this project without Joseph Kain's blog on writing a debugger in Rust and C. It's a great read, so I recommend you check it out here.