chain/ethereum: Add provider string to logger on eth_call (#4548)

Author: mangas

chain/ethereum/src/ethereum_adapter.rs

@@ -10,6 +10,7 @@ use graph::data::subgraph::API_VERSION_0_0_7;
 use graph::prelude::ethabi::ParamType;
 use graph::prelude::ethabi::Token;
 use graph::prelude::tokio::try_join;
+use graph::slog::o;
 use graph::{
     blockchain::{block_stream::BlockWithTriggers, BlockPtr, IngestorError},
     prelude::{
@@ -426,6 +427,7 @@ impl EthereumAdapter {
         block_ptr: BlockPtr,
     ) -> impl Future<Item = Bytes, Error = EthereumContractCallError> + Send {
         let web3 = self.web3.clone();
+        let logger = Logger::new(&logger, o!("provider" => self.provider.clone()));
 
         // Ganache does not support calls by block hash.
         // See https://github.com/trufflesuite/ganache-cli/issues/973