Crate vergen

Generate build time information for use within a project.

vergen, when used in conjunction with the Build Scripts support in cargo, can either

1. Generate environment variables to use with the env! macro. See the documentation for VergenKey for the environment variables names.
2. Generate a file in OUT_DIR (defined by cargo) with up to 8 build time constants. This file can then be used with the include! macro to pull the constants into your source for use.

2.x.x

Example Cargo.toml

[package]
#..
build = "build.rs"

[dependencies]
#..

[build-dependencies]
vergen = "2"

Example build.rs

extern crate vergen;

use vergen::{ConstantsFlags, Result, Vergen};

fn main() {
    gen_constants().expect("Unable to generate vergen constants!");
}

fn gen_constants() -> Result<()> {
    let vergen = Vergen::new(ConstantsFlags::all())?;

    for (k, v) in vergen.build_info() {
        println!("cargo:rustc-env={}={}", k.name(), v);
    }

    Ok(())
}

Use constants in your code

fn my_fn() {
    println!("Build Timestamp: {}", env!("VERGEN_BUILD_TIMESTAMP"));
}

1.x.x

Example build.rs

extern crate vergen;

use vergen::{ConstantsFlags, Result, vergen};

fn main() {
    let mut flags = ConstantsFlags::all();
    flags.toggle(ConstantsFlags::BUILD_TIMESTAMP);
    vergen(flags).expect("Unable to generate constants!");
}

Example version.rs

/// Compile Time (UTC)
pub const VERGEN_BUILD_TIMESTAMP: &str = "2018-08-09T15:15:57.282334589+00:00";

/// Compile Time - Short (UTC)
pub const VERGEN_BUILD_DATE: &str = "2018-08-09";

/// Commit SHA
pub const VERGEN_SHA: &str = "75b390dc6c05a6a4aa2791cc7b3934591803bc22";

/// Commit SHA - Short
pub const VERGEN_SHA_SHORT: &str = "75b390d";

/// Commit Date
pub const VERGEN_COMMIT_DATE: &str = "2018-08-08";

/// Target Triple
pub const VERGEN_TARGET_TRIPLE: &str = "x86_64-unknown-linux-gnu";

/// Semver
pub const VERGEN_SEMVER: &str = "v0.1.0-pre.0";

/// Semver (Lightweight)
pub const VERGEN_SEMVER_LIGHTWEIGHT: &str = "v0.1.0-pre.0";

Include the constants in your code (Version 1.x.x only)

include!(concat!(env!("OUT_DIR"), "/version.rs"));

format!("{} {} blah {}", VERGEN_BUILD_TIMESTAMP, VERGEN_SHA, VERGEN_SEMVER)

Structs

ConstantsFlags	Constants Flags
Vergen	Build time information struct.

Enums

VergenKey

vergen build information keys.

Functions

vergen

Create a version.rs file in OUT_DIR and write the toggled on constants to the file.

Type Definitions

Result

Convenient wrapper around std::Result.