Merge #19550: rpc: Add getindexinfo RPC

124e1ee1343f8bfb3748393ced9debdbdee60d3b doc: Add release notes for getindexinfo RPC (Fabian Jahr)
c447b09458c89c946957a211a4f5373b92af44bf test: Add tests for getindexinfo RPC (Fabian Jahr)
667bc7a7f7c5d9a15eaf6957c3d8841a75efa7bc rpc: Add getindexinfo RPC (Fabian Jahr)

Pull request description:

  As I was playing with indices a I was missing an RPC that gives information about the active indices in the node. I think this can be helpful for many users, especially since there are some new index candidates coming up (#14053, #18000) that can give a quick overview without the user having to parse the logs.

  Feature summary:
  - Adds new RPC `listindices` (placed in Util section)
  - That RPC only lists the actively running indices
  - For each index it gives the name, whether it is synced and up to which block height it is synced

ACKs for top commit:
  laanwj:
    Re-ACK 124e1ee1343f8bfb3748393ced9debdbdee60d3b
  jonatack:
    Code review re-ACK 124e1ee per `git range-diff a57af89 47a5372 124e1ee` no change since my last re-ACK, rebase only

Tree-SHA512: 3b7174c87951e6457fef099f530337803906baf32fb64261410b8def2c0917853d6a1bf3059cd590b1cc1523608f8916dafb327a431d27ecbf8d7454406b5b35

5 files changed, 107 insertions, 0 deletions

diff --git a/doc/release-notes.md b/doc/release-notes.md
index 23983dcd7b..4656963f5a 100644
--- a/doc/release-notes.md
+++ b/doc/release-notes.md
@@ -115,6 +115,10 @@ Changes to Wallet or GUI related RPCs can be found in the GUI or Wallet section
 New RPCs
 --------
 
+- The `getindexinfo` RPC returns the actively running indices of the node,
+  including their current sync status and height. It also accepts an `index_name`
+  to specify returning only the status of that index. (#19550)
+
 Build System
 ------------
 
diff --git a/src/index/base.cpp b/src/index/base.cpp
index f587205a28..e67b813763 100644
--- a/src/index/base.cpp
+++ b/src/index/base.cpp
@@ -319,3 +319,12 @@ void BaseIndex::Stop()
         m_thread_sync.join();
     }
 }
+
+IndexSummary BaseIndex::GetSummary() const
+{
+    IndexSummary summary{};
+    summary.name = GetName();
+    summary.synced = m_synced;
+    summary.best_block_height = m_best_block_index.load()->nHeight;
+    return summary;
+}
diff --git a/src/index/base.h b/src/index/base.h
index 3fab810bb2..74bc1ebfd2 100644
--- a/src/index/base.h
+++ b/src/index/base.h
@@ -13,6 +13,12 @@
 
 class CBlockIndex;
 
+struct IndexSummary {
+    std::string name;
+    bool synced{false};
+    int best_block_height{0};
+};
+
 /**
  * Base class for indices of blockchain data. This implements
  * CValidationInterface and ensures blocks are indexed sequentially according
@@ -106,6 +112,9 @@ public:
 
     /// Stops the instance from staying in sync with blockchain updates.
     void Stop();
+
+    /// Get a summary of the index and its state.
+    IndexSummary GetSummary() const;
 };
 
 #endif // BITCOIN_INDEX_BASE_H
diff --git a/src/rpc/misc.cpp b/src/rpc/misc.cpp
index ff31bee1e3..0c982317f5 100644
--- a/src/rpc/misc.cpp
+++ b/src/rpc/misc.cpp
@@ -4,6 +4,8 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <httpserver.h>
+#include <index/blockfilterindex.h>
+#include <index/txindex.h>
 #include <interfaces/chain.h>
 #include <key_io.h>
 #include <node/context.h>
@@ -636,6 +638,60 @@ static RPCHelpMan echo(const std::string& name)
 static RPCHelpMan echo() { return echo("echo"); }
 static RPCHelpMan echojson() { return echo("echojson"); }
 
+static UniValue SummaryToJSON(const IndexSummary&& summary, std::string index_name)
+{
+    UniValue ret_summary(UniValue::VOBJ);
+    if (!index_name.empty() && index_name != summary.name) return ret_summary;
+
+    UniValue entry(UniValue::VOBJ);
+    entry.pushKV("synced", summary.synced);
+    entry.pushKV("best_block_height", summary.best_block_height);
+    ret_summary.pushKV(summary.name, entry);
+    return ret_summary;
+}
+
+static RPCHelpMan getindexinfo()
+{
+    return RPCHelpMan{"getindexinfo",
+                "\nReturns the status of one or all available indices currently running in the node.\n",
+                {
+                    {"index_name", RPCArg::Type::STR, RPCArg::Optional::OMITTED_NAMED_ARG, "Filter results for an index with a specific name."},
+                },
+                RPCResult{
+                    RPCResult::Type::OBJ, "", "", {
+                        {
+                            RPCResult::Type::OBJ, "name", "The name of the index",
+                            {
+                                {RPCResult::Type::BOOL, "synced", "Whether the index is synced or not"},
+                                {RPCResult::Type::NUM, "best_block_height", "The block height to which the index is synced"},
+                            }
+                        },
+                    },
+                },
+                RPCExamples{
+                    HelpExampleCli("getindexinfo", "")
+                  + HelpExampleRpc("getindexinfo", "")
+                  + HelpExampleCli("getindexinfo", "txindex")
+                  + HelpExampleRpc("getindexinfo", "txindex")
+                },
+                [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
+{
+    UniValue result(UniValue::VOBJ);
+    const std::string index_name = request.params[0].isNull() ? "" : request.params[0].get_str();
+
+    if (g_txindex) {
+        result.pushKVs(SummaryToJSON(g_txindex->GetSummary(), index_name));
+    }
+
+    ForEachBlockFilterIndex([&result, &index_name](const BlockFilterIndex& index) {
+        result.pushKVs(SummaryToJSON(index.GetSummary(), index_name));
+    });
+
+    return result;
+},
+    };
+}
+
 void RegisterMiscRPCCommands(CRPCTable &t)
 {
 // clang-format off
@@ -650,6 +706,7 @@ static const CRPCCommand commands[] =
     { "util",               "getdescriptorinfo",      &getdescriptorinfo,      {"descriptor"} },
     { "util",               "verifymessage",          &verifymessage,          {"address","signature","message"} },
     { "util",               "signmessagewithprivkey", &signmessagewithprivkey, {"privkey","message"} },
+    { "util",               "getindexinfo",           &getindexinfo,           {"index_name"} },
 
     /* Not shown in help */
     { "hidden",             "setmocktime",            &setmocktime,            {"timestamp"}},
diff --git a/test/functional/rpc_misc.py b/test/functional/rpc_misc.py
index cc5a264adb..0493ceeb64 100755
--- a/test/functional/rpc_misc.py
+++ b/test/functional/rpc_misc.py
@@ -61,6 +61,34 @@ class RpcMiscTest(BitcoinTestFramework):
         node.logging(include=['qt'])
         assert_equal(node.logging()['qt'], True)
 
+        self.log.info("test getindexinfo")
+        # Without any indices running the RPC returns an empty object
+        assert_equal(node.getindexinfo(), {})
+
+        # Restart the node with indices and wait for them to sync
+        self.restart_node(0, ["-txindex", "-blockfilterindex"])
+        self.wait_until(lambda: all(i["synced"] for i in node.getindexinfo().values()))
+
+        # Returns a list of all running indices by default
+        assert_equal(
+            node.getindexinfo(),
+            {
+                "txindex": {"synced": True, "best_block_height": 200},
+                "basic block filter index": {"synced": True, "best_block_height": 200}
+            }
+        )
+
+        # Specifying an index by name returns only the status of that index
+        assert_equal(
+            node.getindexinfo("txindex"),
+            {
+                "txindex": {"synced": True, "best_block_height": 200},
+            }
+        )
+
+        # Specifying an unknown index name returns an empty result
+        assert_equal(node.getindexinfo("foo"), {})
+
 
 if __name__ == '__main__':
     RpcMiscTest().main()