chainrpc: return Unavailable while notifier starts
What the developer wrote
Authored by Boris Nagaev
chainrpc: return Unavailable while notifier starts
From v0.20.0-rc3 (commit c6f458e478f9ef2cf1d394972bfbc512862c6707) onward
the ChainNotifier sub-server may still be initialising when clients attempt
to subscribe, currently resulting in a gRPC Unknown error with a plain-text
message. Change the notifier RPC endpoints to return codes.Unavailable instead
so clients can reliably interpret the condition as "retry later" and handle
the startup lag without unstable string matching.
What changed, and why it matters
This commit changes the error code returned when LND's ChainNotifier sub-server is still starting up. Previously, clients received a generic 'Unknown' gRPC error with a text message; now they receive a standard 'Unavailable' code, which is the normal signal to retry later. It is a reliability improvement, not a security fix.
No security action required; treat as a normal reliability/usability improvement. Clients may optionally update retry logic to rely on codes.Unavailable.
Security signals we found
Error-code hygiene improvement
No privilege boundary change
No input validation change
No cryptographic change
Evidence from the diff
The patch converts ErrChainNotifierServerNotActive from a plain errors.New() into a gRPC status.Error with codes.Unavailable. This lets gRPC clients detect the transient startup condition programmatically instead of parsing an error string. No logic, authorization, or data-handling behavior changes.
Changed components
lnrpc/chainrpc/chain_server.goChainNotifier gRPC sub-serverInspect captured patch +4 / −2
diff --git a/lnrpc/chainrpc/chain_server.go b/lnrpc/chainrpc/chain_server.go
index da68e03..e42a684 100644
--- a/lnrpc/chainrpc/chain_server.go
+++ b/lnrpc/chainrpc/chain_server.go
@@ -18,6 +18,8 @@ import (
"github.com/lightningnetwork/lnd/lnrpc"
"github.com/lightningnetwork/lnd/macaroons"
"google.golang.org/grpc"
+ "google.golang.org/grpc/codes"
+ "google.golang.org/grpc/status"
"gopkg.in/macaroon-bakery.v2/bakery"
)
@@ -84,8 +86,8 @@ var (
// ErrChainNotifierServerNotActive indicates that the chain notifier hasn't
// finished the startup process.
- ErrChainNotifierServerNotActive = errors.New("chain notifier RPC is " +
- "still in the process of starting")
+ ErrChainNotifierServerNotActive = status.Error(codes.Unavailable,
+ "chain notifier RPC is still in the process of starting")
)
// ServerShell is a shell struct holding a reference to the actual sub-server.
Why this scored 22/100
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