1 files changed, 39 insertions, 0 deletions
diff --git a/build.rs b/build.rs
new file mode 100644
index 00000000..f3e6ea33
--- /dev/null
+++ b/build.rs
@@ -0,0 +1,39 @@
+use std::process::Command;
+
+fn main() {
+    read_git_info().expect("Unable to read Git info");
+}
+
+fn run(args: &[&str]) -> Result<String, std::io::Error> {
+    let out = Command::new(args[0]).args(&args[1..]).output()?;
+    Ok(String::from_utf8(out.stdout).unwrap().trim().to_string())
+}
+
+/// This method reads info from Git, namely tags, branch, and revision
+fn read_git_info() -> Result<(), std::io::Error> {
+    // The exact tag for the current commit, can be empty when
+    // the current commit doesn't have an associated tag
+    let exact_tag = run(&["git", "describe", "--abbrev=0", "--tags", "--exact-match"])?;
+    println!("cargo:rustc-env=GIT_EXACT_TAG={}", exact_tag);
+
+    // The last available tag, equal to exact_tag when
+    // the current commit is tagged
+    let last_tag = run(&["git", "describe", "--abbrev=0", "--tags"])?;
+    println!("cargo:rustc-env=GIT_LAST_TAG={}", last_tag);
+
+    // The current branch name
+    let branch = run(&["git", "rev-parse", "--abbrev-ref", "HEAD"])?;
+    println!("cargo:rustc-env=GIT_BRANCH={}", branch);
+
+    // The current git commit hash
+    let rev = run(&["git", "rev-parse", "HEAD"])?;
+    let rev_short = rev.get(..12).unwrap_or_default();
+    println!("cargo:rustc-env=GIT_REV={}", rev_short);
+
+    // To access these values, use:
+    //    env!("GIT_EXACT_TAG")
+    //    env!("GIT_LAST_TAG")
+    //    env!("GIT_BRANCH")
+    //    env!("GIT_REV")
+    Ok(())
+}