Error handling in WS code is broken

[tzdybal]

There are multiple issues with error handling in WebSocket handling code. Happy-path works fine, but in case of errors, code panics.

[jbowen93]

Logs from a panic:

...
8:12PM ERR expected text message
8:12PM ERR expected text message
8:12PM ERR expected text message
8:12PM ERR expected text message
8:12PM ERR expected text message
8:12PM ERR expected text message
8:12PM ERR expected text message
8:12PM ERR expected text message
8:12PM ERR expected text message
8:12PM ERR expected text message
8:12PM ERR expected text message
8:12PM ERR expected text message
2022/05/11 20:12:04 http: panic serving 127.0.0.1:47362: repeated read on failed websocket connection
goroutine 74 [running]:
net/http.(*conn).serve.func1()
	/usr/local/go/src/net/http/server.go:1802 +0xb9
panic({0x1d7c780, 0x2771ab0})
	/usr/local/go/src/runtime/panic.go:1047 +0x266
github.com/gorilla/websocket.(*Conn).NextReader(0xc008d1c9a0)
	/go/pkg/mod/github.com/gorilla/websocket@v1.5.0/conn.go:1030 +0x269
github.com/celestiaorg/optimint/rpc/json.(*handler).wsHandler(0xc0083a82d0, {0x27c67d0, 0xc008590540}, 0xc0084a6a78)
	/go/pkg/mod/github.com/celestiaorg/optimint@v0.1.2/rpc/json/ws.go:62 +0x31a
net/http.HandlerFunc.ServeHTTP(0x3b, {0x27c67d0, 0xc008590540}, 0x0)
	/usr/local/go/src/net/http/server.go:2047 +0x2f
net/http.(*ServeMux).ServeHTTP(0xc0085ebe10, {0x27c67d0, 0xc008590540}, 0xc008bfea00)
	/usr/local/go/src/net/http/server.go:2425 +0x149
github.com/celestiaorg/optimint/rpc/json.(*handler).ServeHTTP(0x0, {0x27c67d0, 0xc008590540}, 0x48410e)
	/go/pkg/mod/github.com/celestiaorg/optimint@v0.1.2/rpc/json/handler.go:44 +0x27
net/http.serverHandler.ServeHTTP({0xc008d106c0}, {0x27c67d0, 0xc008590540}, 0xc008bfea00)
	/usr/local/go/src/net/http/server.go:2879 +0x43b
net/http.(*conn).serve(0xc008bf46e0, {0x27ee9b8, 0xc001cea270})
	/usr/local/go/src/net/http/server.go:1930 +0xb08
created by net/http.(*Server).Serve
	/usr/local/go/src/net/http/server.go:3034 +0x4e8

[jbowen93]

I'm going to prioritize this because it has bothered me for too long

[jbowen93]

First step can be to change https://github.com/celestiaorg/optimint/blob/main/rpc/json/ws.go#L68 from

h.logger.Error("expected text message")

to

h.logger.Debug("expected text message")