{"id":238017,"date":"2021-09-03T06:37:00","date_gmt":"2021-09-03T10:37:00","guid":{"rendered":"https:\/\/wordpress-756359-3782526.cloudwaysapps.com\/?p=238017"},"modified":"2024-09-30T07:26:34","modified_gmt":"2024-09-30T07:26:34","slug":"2021-09-03-rust","status":"publish","type":"post","link":"https:\/\/www.travis-ci.com\/blog\/2021-09-03-rust\/","title":{"rendered":"Speedy Builds with Rust"},"content":{"rendered":"\n

Rust is a multi-paradigm, high-level, general-purpose programming language designed for performance and safety, especially safe concurrency. In today\u2019s post we are using Rust nightly<\/code>. You can also add more targets like stable<\/code> or beta<\/code>, but we are going to show you the power or utilizing caching when it comes to building in Rust on Travis.<\/p>\n\n\n\n

Rust and Travis<\/h2>\n\n\n\n

Rust builds are notoriously slow, especially when compiling from a clean slate. This is less true than it once was, but it\u2019s still slow enough to be a significant problem for CI systems. So I thought why not write something that will help future Rust builders using Travis?<\/p>\n\n\n\n

Slow down, you\u2019re going too fast<\/h2>\n\n\n\n

Actually, you\u2019re doing just fine. The good news is, is that we can use cache: cargo<\/code>, and a few other things up our builders sleeves to help the speed of builds in Rust. For example, take a look at this .travis.yml<\/code> I wrote:<\/p>\n\n\n\n

---\ncache: cargo\ndist: xenial\nlanguage: rust\nmatrix:\n  allow_failures:\n    - rust: nightly\n  before_cache: \n    - rm -rf ~\/.cargo\/registry\/index\/ # Remove cache files \n    - rm -f  .\/target\/.rustc_info.json # Remove more cache files that are recursively brought back upon a triggered build\n    - find .\/target\/debug -maxdepth 1 -type f -delete # Delete loose files \n  fast_finish: true\nos: linux\nrust:\n  - stable\n  - beta\n  - nightly\nscript:\n  - \"cargo build --verbose --all\"\n  - \"cargo test --verbose --all\"<\/code><\/pre>\n\n\n\n
We are testing against 3 Rust channels here, on occassion nightly<\/code> will fail due to the compiler, but since this post is about speeding up your builds, you\u2019ll notice I put in a conditional, that is, allowing failures from only one Rust channel, and that is nightly<\/code>:<\/p>\n\n\n\n
matrix:\n  allow_failures:\n    - rust: nightly<\/code><\/pre>\n\n\n\n
You\u2019ll notice stable<\/code> and beta<\/code> are not listed along with nightly<\/code>. Now since speed is the center of this post, you may want to disable Cargo\u2019s incremental compilation, as it doesn\u2019t really give any more verbosity to the build, so let\u2019s try removing it for even faster builds. In order to do this, you\u2019ll need to set the CARGO_INCREMENTAL<\/code> env var<\/code> to 0<\/code>.<\/p>\n\n\n\n
Tests<\/h2>\n\n\n\n
Now, let\u2019s make a test file, here\u2019s some Rust code, you\u2019re free to name it whatever you like, in this case you can see we named our file test_run<\/code>:<\/p>\n\n\n\n
extern crate test_run;\n\nuse logic_gates::{and, xor};\n\npub type Sum = u8;\npub type Carry = u8;\n\npub fn half_adder_input_output() -> Vec<((u8, u8), (Sum, Carry))> { \n    vec![\n        ((0, 0), (0, 0)), \n        ((0, 1), (1, 0)), \n        ((1, 0), (1, 0)), \n        ((1, 1), (0, 1)), \n    ] \n}\n\nfn half_adder(a: u8, b: u8) -> (Sum, Carry) {\n    (xor(a, b), and(a, b))\n}\n\n#[test]\nfn one_bit_adder() {\n    for (inn, out) in half_adder_input_output() {\n        let (a, b) = inn;\n        assert_eq!(half_adder(a, b), out);\n    }\n}<\/code><\/pre>\n\n\n\n
Looks good builders, now let\u2019s go over what we have:<\/p>\n\n\n\n