Connection Closed: Unable to decode header

[datalatics-official]

When try to make connection with proxy service. It logs a message that "unable to decode hearder" and close the connection. Need to fix is soon. Please find the attach error's screenshot.

When we try to run it with --debug.

@mpenick

[mpenick]

What driver and its version is connecting to the proxy?

[mpenick]

It looks like you might be using java-driver 2.1.X. This isn't currently supported for a couple reasons:

1. This is the easier problem to solve. The 2.X driver using the CQL protocol v3, and cql-proxy currently hard codes the version to v4. This small patch fixes that issue:

diff --git a/proxy.go b/proxy.go
index 5af2412..b7b073c 100644
--- a/proxy.go
+++ b/proxy.go
@@ -83,7 +83,7 @@ func main() {
 	}
 
 	p := proxy.NewProxy(ctx, proxy.Config{
-		Version:           primitive.ProtocolVersion4,
+		Version:           primitive.ProtocolVersion3,
 		Resolver:          resolver,
 		ReconnectPolicy:   proxycore.NewReconnectPolicy(),
 		NumConns:          1,

However, this is not an actual fix though. My thought is the proxy should allow clients to be connected to the backend using multiple protocol versions simultaneously. It could have a session cache for each version.

2. The bigger problem is Astra doesn't not support the legacy schema tables that used to live under system. It's possible that the proxy could intercept these calls and do some type of conversion to/from the new schema tables under system_schema. This could be a lot of work, but maybe only a subset needs to be supported to get older drivers working properly.

Exception in thread "main" com.datastax.driver.core.exceptions.NoHostAvailableException: All host(s) tried for query failed (tried: /127.0.0.1:9042 (com.datastax.driver.core.exceptions.InvalidQueryException: table system.schema_keyspaces does not exist))
	at com.datastax.driver.core.ControlConnection.reconnectInternal(ControlConnection.java:240)
	at com.datastax.driver.core.ControlConnection.connect(ControlConnection.java:86)
	at com.datastax.driver.core.Cluster$Manager.init(Cluster.java:1455)
	at com.datastax.driver.core.Cluster.init(Cluster.java:158)
	at com.datastax.driver.core.Cluster.connectAsync(Cluster.java:329)
	at com.datastax.driver.core.Cluster.connect(Cluster.java:279)
	at org.example.App.main(App.java:21)

[mpenick]

I've created issues to track handling these two issues:

1. Handle mixed protocol versions e.g. client = V5, server = V4 #7
2. Convert system schema tables to/from system_schema tables #51

[mpenick]

This fixes both issues #52 enough to allow connecting older versions of drivers; however, the server/client still share the same protocol, but the proxy can support multiple protocols at one time for different client connection. For schema under system the proxy just returns empty tables which is enough to allow the driver to connect and start running queries.

[datalatics-official]

What driver and its version is connecting to the proxy?

"com.datastax.cassandra" % "cassandra-driver-core" % "2.1.10.3"

[mpenick]

Released https://github.com/datastax/cql-proxy/releases/tag/v0.0.4. Let me know if this fixes your issue.

[datalatics-official]

Thank you @mpenick