init: move asmap code earlier in init process

and update feature_asmap.py and test_runner.py

This commit moves the asmap init.cpp code from the end of "Step 12: start node"
to "Step 6: network initialization" to provide feedback on passing an -asmap
config arg much more quickly. This change speeds up the feature_asmap.py
functional test file from 60 to 5 seconds by accelerating the 2 tests that use
`assert_start_raises_init_error`.

Credit to Wladimir J. van der Laan for the suggestion.

src/init.cpp

@@ -1418,6 +1418,31 @@ bool AppInitMain(NodeContext& node)
             return InitError(ResolveErrMsg("externalip", strAddr));
     }
 
+    // Read asmap file if configured
+    if (gArgs.IsArgSet("-asmap")) {
+        fs::path asmap_path = fs::path(gArgs.GetArg("-asmap", ""));
+        if (asmap_path.empty()) {
+            asmap_path = DEFAULT_ASMAP_FILENAME;
+        }
+        if (!asmap_path.is_absolute()) {
+            asmap_path = GetDataDir() / asmap_path;
+        }
+        if (!fs::exists(asmap_path)) {
+            InitError(strprintf(_("Could not find asmap file %s").translated, asmap_path));
+            return false;
+        }
+        std::vector<bool> asmap = CAddrMan::DecodeAsmap(asmap_path);
+        if (asmap.size() == 0) {
+            InitError(strprintf(_("Could not parse asmap file %s").translated, asmap_path));
+            return false;
+        }
+        const uint256 asmap_version = SerializeHash(asmap);
+        node.connman->SetAsmap(std::move(asmap));
+        LogPrintf("Using asmap version %s for IP bucketing\n", asmap_version.ToString());
+    } else {
+        LogPrintf("Using /16 prefix for IP bucketing\n");
+    }
+
 #if ENABLE_ZMQ
     g_zmq_notification_interface = CZMQNotificationInterface::Create();
 
@@ -1825,31 +1850,6 @@ bool AppInitMain(NodeContext& node)
         return false;
     }
 
-    // Read asmap file if configured
-    if (gArgs.IsArgSet("-asmap")) {
-        fs::path asmap_path = fs::path(gArgs.GetArg("-asmap", ""));
-        if (asmap_path.empty()) {
-            asmap_path = DEFAULT_ASMAP_FILENAME;
-        }
-        if (!asmap_path.is_absolute()) {
-            asmap_path = GetDataDir() / asmap_path;
-        }
-        if (!fs::exists(asmap_path)) {
-            InitError(strprintf(_("Could not find asmap file %s").translated, asmap_path));
-            return false;
-        }
-        std::vector<bool> asmap = CAddrMan::DecodeAsmap(asmap_path);
-        if (asmap.size() == 0) {
-            InitError(strprintf(_("Could not parse asmap file %s").translated, asmap_path));
-            return false;
-        }
-        const uint256 asmap_version = SerializeHash(asmap);
-        node.connman->SetAsmap(std::move(asmap));
-        LogPrintf("Using asmap version %s for IP bucketing\n", asmap_version.ToString());
-    } else {
-        LogPrintf("Using /16 prefix for IP bucketing\n");
-    }
-
     // ********************************************************* Step 13: finished
 
     SetRPCWarmupFinished();

test/functional/feature_asmap.py

@@ -18,8 +18,7 @@ Verify node behaviour and debug log when launching bitcoind in these cases:
 
 6. `bitcoind -asmap` with an empty (unparsable) default asmap file
 
-The tests are order-independent. The slowest tests (missing default asmap and
+The tests are order-independent.
-empty asmap) are placed last.
 
 """
 import os

test/functional/test_runner.py

@@ -101,7 +101,6 @@ BASE_SCRIPTS = [
     'rpc_txoutproof.py',
     'wallet_listreceivedby.py',
     'wallet_abandonconflict.py',
-    'feature_asmap.py',
     'feature_csv_activation.py',
     'rpc_rawtransaction.py',
     'wallet_address_types.py',
@@ -207,6 +206,7 @@ BASE_SCRIPTS = [
     'p2p_dos_header_tree.py',
     'p2p_unrequested_blocks.py',
     'feature_includeconf.py',
+    'feature_asmap.py',
     'rpc_deriveaddresses.py',
     'rpc_deriveaddresses.py --usecli',
     'rpc_scantxoutset.py',