add rpc call to get chronos futures at runtime

beacon_chain/rpc/nimbus_api.nim

@@ -6,6 +6,7 @@
 
 import
   std/strutils,
+  chronos,
   stew/shims/macros,
   stew/byteutils,
   json_rpc/[rpcserver, jsonmarshal],
@@ -18,6 +19,15 @@ logScope: topics = "nimbusapi"
 type
   RpcServer = RpcHttpServer
 
+when defined(chronosFutureTracking):
+  type
+    FutureInfo* = object
+      id*: int
+      procname*: string
+      filename*: string
+      line*: int
+      state: string
+
 proc installNimbusApiHandlers*(rpcServer: RpcServer, node: BeaconNode) =
   ## Install non-standard api handlers - some of these are used by 3rd-parties
   ## such as eth2stats, pending a full REST api
@@ -88,3 +98,19 @@ proc installNimbusApiHandlers*(rpcServer: RpcServer, node: BeaconNode) =
     {.gcsafe.}: # It's probably not, actually. Hopefully we don't log from threads...
       updateLogLevel(level)
     return true
+
+  when defined(chronosFutureTracking):
+    rpcServer.rpc("getChronosFutures") do () -> seq[FutureInfo]:
+      var res: seq[FutureInfo]
+
+      for item in pendingFutures():
+        let loc = item.location[LocCreateIndex][]
+        res.add FutureInfo(
+          id: item.id,
+          procname: $loc.procedure,
+          filename: $loc.file,
+          line: loc.line,
+          state: $item.state
+        )
+
+      return res

docs/the_nimbus_book/src/api.md

@@ -183,3 +183,11 @@ Set the current logging level dynamically: TRACE, DEBUG, INFO, NOTICE, WARN, ERR
 ```
 curl -d '{"jsonrpc":"2.0","id":"id","method":"setLogLevel","params":["DEBUG; TRACE:discv5,libp2p; REQUIRED:none; DISABLED:none"] }' -H 'Content-Type: application/json' localhost:9190 -s | jq
 ```
+
+### getChronosFutures
+
+Get the current list of live async futures in the process - compile with `-d:chronosFutureTracking` to enable.
+
+```
+curl -d '{"jsonrpc":"2.0","id":"id","method":"getChronosFutures","params":[] }' -H 'Content-Type: application/json' localhost:9190 -s | jq '.result | (.[0] | keys_unsorted) as $keys | $keys, map([.[ $keys[] ]])[] | @csv'
+```

vendor/nim-chronos

@@ -1 +1 @@
-Subproject commit 1ffd1cd3dc2145b6922eba465d29d1990e9d4254
+Subproject commit 710454cc6b792748144882d7c97912b0c6cef138