Log app info at its start [ECR-3150] (#905)

Log info about the app version and build mode at the app's start.

Author: skletsun

exonum-java-binding/core/rust/Cargo.lock

@@ -13,6 +13,7 @@ exonum-configuration = "0.11"
 exonum-btc-anchoring = "0.11"
 exonum-time = "0.11"
 env_logger = "0.6.1"
+log = "0.4"
 toml = "0.4.6"
 serde = "1.0"
 serde_derive = "1.0"

exonum-java-binding/core/rust/exonum-java/Cargo.toml

@@ -19,17 +19,39 @@ extern crate exonum_btc_anchoring;
 extern crate exonum_configuration;
 extern crate exonum_time;
 extern crate java_bindings;
+#[macro_use]
+extern crate log;
 
 #[cfg(test)]
 extern crate tempfile;
 
+use java_bindings::get_lib_version;
+
 mod node_builder;
 
 fn main() {
     env_logger::init();
     // Panic if `_JAVA_OPTIONS` environmental variable is set.
     java_bindings::panic_if_java_options();
 
+    // Log app's metadata
+    log_app_metadata();
+
     let builder = node_builder::create();
     builder.run()
 }
+
+// Prints info about version and build mode of started app to the STDOUT.
+fn log_app_metadata() {
+    let version = get_lib_version();
+    let build_type = if cfg!(debug_assertions) {
+        "debug"
+    } else {
+        "release"
+    };
+
+    info!(
+        "Started Exonum Java {} (built in {} mode)",
+        version, build_type
+    );
+}

exonum-java-binding/core/rust/exonum-java/src/main.rs

@@ -23,8 +23,8 @@ pub extern "system" fn Java_com_exonum_binding_util_LibraryLoader_nativeGetLibra
     env.new_string(get_lib_version()).unwrap().into_inner()
 }
 
-// Returns the exact value of the `version` field from the library's Cargo.toml configuration file.
-fn get_lib_version() -> &'static str {
+/// Returns the exact value of the `version` field from the library's Cargo.toml configuration file.
+pub fn get_lib_version() -> &'static str {
     env!("CARGO_PKG_VERSION")
 }
 

exonum-java-binding/core/rust/src/runtime/library_loader.rs

@@ -25,5 +25,6 @@ mod time_service;
 
 pub use self::config::*;
 pub use self::java_service_runtime::JavaServiceRuntime;
+pub use self::library_loader::get_lib_version;
 pub use self::paths::panic_if_java_options;
 pub use self::service_factory_adapter::JavaServiceFactoryAdapter;