RPC error handling for implemented endpoints

[austinabell]

Error logs are not output through the API process and are ignored in execution. This adds error handling to the three endpoints which sends the error back as the response to the client

Through this I have found that:

1. Historical queries aren't actually functional as of now (it was implied that specifying height to ABCI query would query state at that height):

curl -X POST --data '{"jsonrpc":"2.0","method":"eth_getCode","params":["0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b","0x2"],"id":1}' -H "Content-Type: application/json" http://localhost:8545/rpc
 > {"jsonrpc":"2.0","id":1,"error":{"code":-32000,"message":"{\"codespace\":\"sdk\",\"code\":1,\"message\":\"failed to load state at height 2; version does not exist (latest height: 3)\"}"}}

2. There was an error retrieving the state (possibly due to state transition but I won't explore further right now):

curl -X POST --data '{"jsonrpc":"2.0","method":"eth_getCode","params":["0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b","0x2"],"id":1}' -H "Content-Type: application/json" http://localhost:8545/rpc
 > {"jsonrpc":"2.0","id":1,"error":{"code":-32000,"message":"ABCIQuery: response error: RPC error -32603 - Internal error: runtime error: invalid memory address or nil pointer dereference"}}

Error log on daemon process:

E[2019-08-30|16:25:39.267] Panic in RPC HTTP handler                    module=rpc-server err="runtime error: invalid memory address or nil pointer dereference" stack="goroutine 138 [running]:\nruntime/debug.Stack(0xc000bfdb20, 0x4d25ba0, 0x5c33690)\n\t/usr/local/go/src/runtime/debug/stack.go:24 +0x9d\ngithub.com/tendermint/tendermint/rpc/lib/server.RecoverAndLogHandler.func1.1(0xc002231180, 0x529bde0, 0xc000a92dc0, 0xbf527f70cfd6f650, 0x2e8b4d49e, 0x5c4fb20, 0xc000bccf00)\n\t/Users/austinabell/go/pkg/mod/github.com/tendermint/[email protected]/rpc/lib/server/http_server.go:161 +0x552\npanic(0x4d25ba0, 0x5c33690)\n\t/usr/local/go/src/runtime/panic.go:522 +0x1b5\ngithub.com/cosmos/ethermint/x/evm/types.(*CommitStateDB).WithContext(...)\n\t/Users/austinabell/development/github.com/chainsafe/ethermint/x/evm/types/statedb.go:100\ngithub.com/cosmos/ethermint/x/evm.(*Keeper).GetCode(...)\n\t/Users/austinabell/development/github.com/chainsafe/ethermint/x/evm/keeper.go:126\ngithub.com/cosmos/ethermint/x/evm.queryCode(0x529b2a0, 0xc0000b6008, 0x52adbe0, 0xc000b6bc00, 0xa, 0x0, 0x0, 0x0, 0x0, 0x0, ...)\n\t/Users/austinabell/development/github.com/chainsafe/ethermint/x/evm/querier.go:97 +0x165\ngithub.com/cosmos/ethermint/x/evm.NewQuerier.func1(0x529b2a0, 0xc0000b6008, 0x52adbe0, 0xc000b6bc00, 0xa, 0x0, 0x0, 0x0, 0x0, 0x0, ...)\n\t/Users/austinabell/development/github.com/chainsafe/ethermint/x/evm/querier.go:36 +0x230\ngithub.com/cosmos/cosmos-sdk/baseapp.handleQueryCustom(0xc000142b40, 0xc000b6bbc0, 0x4, 0x4, 0x5c7b1a0, 0x0, 0x0, 0xc002223e00, 0x3e, 0x2, ...)\n\t/Users/austinabell/go/pkg/mod/github.com/cosmos/[email protected]/baseapp/baseapp.go:588 +0x5b3\ngithub.com/cosmos/cosmos-sdk/baseapp.(*BaseApp).Query(0xc000142b40, 0x5c7b1a0, 0x0, 0x0, 0xc002223e00, 0x3e, 0x2, 0x0, 0x0, 0x0, ...)\n\t/Users/austinabell/go/pkg/mod/github.com/cosmos/[email protected]/baseapp/baseapp.go:463 +0x2e9\ngithub.com/tendermint/tendermint/abci/client.(*localClient).QuerySync(0xc0000c7800, 0x5c7b1a0, 0x0, 0x0, 0xc002223e00, 0x3e, 0x2, 0x0, 0x0, 0x0, ...)\n\t/Users/austinabell/go/pkg/mod/github.com/tendermint/[email protected]/abci/client/local_client.go:207 +0xf3\ngithub.com/tendermint/tendermint/proxy.(*appConnQuery).QuerySync(0xc000b7eee0, 0x5c7b1a0, 0x0, 0x0, 0xc002223e00, 0x3e, 0x2, 0x0, 0x0, 0x0, ...)\n\t/Users/austinabell/go/pkg/mod/github.com/tendermint/[email protected]/proxy/app_conn.go:143 +0x6d\ngithub.com/tendermint/tendermint/rpc/core.ABCIQuery(0xc0022311c0, 0xc002223e00, 0x3e, 0x5c7b1a0, 0x0, 0x0, 0x2, 0x0, 0x0, 0x0, ...)\n\t/Users/austinabell/go/pkg/mod/github.com/tendermint/[email protected]/rpc/core/abci.go:57 +0x114\nreflect.Value.call(0x4d3d2c0, 0x508bc78, 0x13, 0x4e8d19e, 0x4, 0xc000399e80, 0x5, 0x5, 0x5, 0xc000399e80, ...)\n\t/usr/local/go/src/reflect/value.go:447 +0x461\nreflect.Value.Call(0x4d3d2c0, 0x508bc78, 0x13, 0xc000399e80, 0x5, 0x5, 0x4, 0x4, 0x0)\n\t/usr/local/go/src/reflect/value.go:308 +0xa4\ngithub.com/tendermint/tendermint/rpc/lib/server.makeJSONRPCHandler.func1(0x52959a0, 0xc002231180, 0xc000bccf00)\n\t/Users/austinabell/go/pkg/mod/github.com/tendermint/[email protected]/rpc/lib/server/handlers.go:157 +0x90a\ngithub.com/tendermint/tendermint/rpc/lib/server.handleInvalidJSONRPCPaths.func1(0x52959a0, 0xc002231180, 0xc000bccf00)\n\t/Users/austinabell/go/pkg/mod/github.com/tendermint/[email protected]/rpc/lib/server/handlers.go:181 +0x9c\nnet/http.HandlerFunc.ServeHTTP(0xc000b045e0, 0x52959a0, 0xc002231180, 0xc000bccf00)\n\t/usr/local/go/src/net/http/server.go:1995 +0x44\nnet/http.(*ServeMux).ServeHTTP(0xc000b6a2c0, 0x52959a0, 0xc002231180, 0xc000bccf00)\n\t/usr/local/go/src/net/http/server.go:2375 +0x1d6\ngithub.com/tendermint/tendermint/rpc/lib/server.maxBytesHandler.ServeHTTP(0x527b740, 0xc000b6a2c0, 0xf4240, 0x52959a0, 0xc002231180, 0xc000bccf00)\n\t/Users/austinabell/go/pkg/mod/github.com/tendermint/[email protected]/rpc/lib/server/http_server.go:206 +0xd0\ngithub.com/tendermint/tendermint/rpc/lib/server.RecoverAndLogHandler.func1(0x52960a0, 0xc0000fcc40, 0xc000bccf00)\n\t/Users/austinabell/go/pkg/mod/github.com/tendermint/[email protected]/rpc/lib/server/http_server.go:179 +0x317\nnet/http.HandlerFunc.ServeHTTP(0xc000bd5c50, 0x52960a0, 0xc0000fcc40, 0xc000bccf00)\n\t/usr/local/go/src/net/http/server.go:1995 +0x44\nnet/http.serverHandler.ServeHTTP(0xc000979450, 0x52960a0, 0xc0000fcc40, 0xc000bccf00)\n\t/usr/local/go/src/net/http/server.go:2774 +0xa8\nnet/http.(*conn).serve(0xc000bb8000, 0x529b260, 0xc000b6a380)\n\t/usr/local/go/src/net/http/server.go:1878 +0x851\ncreated by net/http.(*Server).Serve\n\t/usr/local/go/src/net/http/server.go:2884 +0x2f4\n"

[ansermino]

What actually happens to these errors? Do they get included in the RPC response? All the test cases I tried just give me "0x" as the return value with no error.

[austinabell]

What actually happens to these errors? Do they get included in the RPC response? All the test cases I tried just give me "0x" as the return value with no error.

The errors do get put in the RPC response, I put the response data for each request in the description (the lines that start with >) and have replicated both errors.

Are you on this branch when you tested this and you rebuilt before running the server process? The previous code would return 0x since that is the default for a nil value using the geth hexutil.Bytes type. The code that was being hit is:

	if err != nil {
		fmt.Printf("could not resolve: %s\n", err)
		return nil
	}

Where the Printf was being ignored and nil was being returned which printed out as 0x in the response

[ansermino]

Definitely messed up something in my previous execution, works beautifully!