Add build script to determine version number from git tag, and make s…

…ure clap knows where to find it

build.rs

@@ -0,0 +1,19 @@
+use std::process::{Command, exit};
+
+fn main() {
+    let version = Command::new("git")
+        .args(&["describe", "--tags", "--always"])
+        .output()
+        .unwrap_or_else(|_| {
+            println!("cargo:warning=VERSION=Unknown");
+            println!("cargo:rustc-env=VERSION=Unknown");
+            exit(0);
+        });
+
+    let version = String::from_utf8(version.stdout)
+        .unwrap()
+        .trim()
+        .to_owned();
+
+    println!("cargo:rustc-env=VERSION={}", version);
+}

src/main.rs

@@ -14,7 +14,7 @@ use serde::Deserialize;
 
 /// Build a database
 #[derive(Parser, Debug)]
-#[clap(author, version, about, long_about = None)]
+#[clap(author, version = env!("VERSION", "No version number set"), about, long_about = None)]
 struct Args {
     ///Path to the log entries to show in table
     #[clap(short, long)]