Add version prints (#69)

Add git commit and git tag (if exists) prints for the Zebra node
startup.

Author: seniakalma

zebrad/build.rs

@@ -6,6 +6,7 @@
 //! When compiling the `lightwalletd` gRPC tests, also builds a gRPC client
 //! Rust API for `lightwalletd`.
 
+use std::process::Command;
 use vergen::EmitBuilder;
 
 /// Returns a new `vergen` builder, configured for everything except for `git` env vars.
@@ -18,6 +19,18 @@ fn base_vergen_builder() -> EmitBuilder {
     vergen
 }
 
+/// Run a git command and return the output, or a fallback value if it fails
+fn run_git_command(args: &[&str], fallback: &str) -> String {
+    Command::new("git")
+        .args(args)
+        .output()
+        .ok()
+        .and_then(|o| String::from_utf8(o.stdout).ok())
+        .map(|s| s.trim().to_string())
+        .filter(|s| !s.is_empty())
+        .unwrap_or_else(|| fallback.to_owned())
+}
+
 /// Process entry point for `zebrad`'s build script
 #[allow(clippy::print_stderr)]
 fn main() {
@@ -52,4 +65,11 @@ fn main() {
             &["tests/common/lightwalletd/proto"],
         )
         .expect("Failed to generate lightwalletd gRPC files");
+
+    // Add custom git tag and commit information
+    let git_tag = run_git_command(&["describe", "--exact-match", "--tags"], "none"); // Will be set to 'none' if .git is missing or git fails.
+    let git_commit = run_git_command(&["rev-parse", "HEAD"], "none"); // Will be set to 'none' if .git is missing or git fails.
+
+    println!("cargo:rustc-env=GIT_TAG={}", git_tag);
+    println!("cargo:rustc-env=GIT_COMMIT_FULL={}", git_commit);
 }

zebrad/src/application.rs

@@ -295,6 +295,8 @@ impl Application for ZebradApp {
         let git_metadata: &[(_, Option<_>)] = &[
             ("branch", option_env!("VERGEN_GIT_BRANCH")),
             ("git commit", Self::git_commit()),
+            ("git tag", option_env!("GIT_TAG")),
+            ("git commit full", option_env!("GIT_COMMIT_FULL")),
             (
                 "commit timestamp",
                 option_env!("VERGEN_GIT_COMMIT_TIMESTAMP"),