add auto-generated Version module to main lib

src/lib/dune

@@ -1,3 +1,10 @@
+(rule
+ (target version.ml)
+ (deps (universe) gen_version.sh)
+ (action
+  (with-stdout-to version.ml
+   (run sh gen_version.sh))))
+
 (library
  (name opentelemetry)
  (public_name opentelemetry)

src/lib/gen_version.sh

@@ -0,0 +1,6 @@
+#!/bin/sh
+v=$(git describe --exact-match HEAD 2>/dev/null | sed 's/^v//')
+[ -z "$v" ] && v=dev
+h=$(git rev-parse HEAD 2>/dev/null)
+[ -z "$h" ] && h=unknown
+printf 'let version = "%s"\nlet git_hash = "%s"\n' "$v" "$h"

src/lib/opentelemetry.ml

@@ -100,6 +100,7 @@ type key_value = Key_value.t
 (** {2 Global settings} *)
 
 module Globals = Globals
+module Version = Version
 
 (** {2 Traces and Spans} *)
 

src/lib/version.mli

@@ -0,0 +1,5 @@
+val version : string
+(** Version of the library, e.g. ["0.12"]. ["dev"] if not built from a release tag. *)
+
+val git_hash : string
+(** Full git commit hash at build time, e.g. ["b92159c1..."]. ["unknown"] if git was unavailable. *)