stratum: start/stop refactoring, add ability to disable stratum server without node restart

src/node/mine_block.rs

@@ -15,6 +15,7 @@
 //! Build a block to mine: gathers transactions from the pool, assembles
 //! them into a block and returns it.
 
+use std::panic::panic_any;
 use chrono::prelude::{DateTime, NaiveDateTime, Utc};
 use rand::{thread_rng, Rng};
 use serde_json::{json, Value};
@@ -33,6 +34,7 @@ use grin_keychain::{ExtKeychain, Identifier, Keychain};
 use grin_servers::ServerTxPool;
 use log::{debug, error, trace, warn};
 use serde_derive::{Deserialize, Serialize};
+use crate::node::stratum::StratumStopState;
 
 /// Fees in block to use for coinbase amount calculation
 /// (Duplicated from Grin wallet project)
@@ -74,6 +76,7 @@ pub fn get_block(
     tx_pool: &ServerTxPool,
     key_id: Option<Identifier>,
     wallet_listener_url: Option<String>,
+    stop_state: &Arc<StratumStopState>
 ) -> (core::Block, BlockFees) {
     let wallet_retry_interval = 5;
     // get the latest chain state and build a block on top of it
@@ -111,6 +114,11 @@ pub fn get_block(
             thread::sleep(Duration::from_millis(100));
         }
 
+        // Stop attempts to build a block on stop.
+        if stop_state.is_stopped() {
+            panic_any("Stopped");
+        }
+
         result = build_block(chain, tx_pool, new_key_id, wallet_listener_url.clone());
     }
     return result.unwrap();
@@ -141,7 +149,6 @@ fn build_block(
     // If this fails for *any* reason then fallback to an empty vec of txs.
     // This will allow us to mine an "empty" block if the txpool is in an
     // invalid (and unexpected) state.
-    println!("12345 prepare_mineable_transactions");
     let txs = match tx_pool.read().prepare_mineable_transactions() {
         Ok(txs) => txs,
         Err(e) => {
@@ -153,7 +160,6 @@ fn build_block(
             vec![]
         }
     };
-    println!("12345 after prepare_mineable_transactions");
 
     // build the coinbase and the block itself
     let fees = txs.iter().map(|tx| tx.fee()).sum();