[3.2] Remove hardcoded 10ms limit for chain_api_plugin calls

[heifner]

Previously http-max-response-time-ms controlled a limit on time for converting internal representation (variant) to a JSON string. Now http-max-response-time-ms will work as described, "Maximum time for processing a request.". It will put a limit on the time for the complete http call for the chain_api_plugin calls specified below.

http-max-response-time-ms now supports -1 for unlimited.

Similar to abi-serializer-max-time-ms, http-max-response-time-ms is time the main thread is blocked. Be careful setting this very large on public API nodes as it does specify a max time that the main thread can be busy servicing an API request and not validating an incoming block. A block production node should not enable the chain_api_plugin as these limits can interfere with block production windows. If chain_api_plugin is enabled on a block production node, make sure to set both http-max-response-time-ms & abi-serializer-max-time-ms to small values to help avoid interference with the block production window.

• http-max-response-time-ms - Controls maximum time of execution of the following chain_api_plugin calls.
  • /v1/chain/get_activated_protocol_features
  • /v1/chain/get_table_rows
  • /v1/chain/get_table_by_scope
  • /v1/chain/get_producers
  • /v1/chain/get_scheduled_transactions

The above API calls now all support an optional time_limit_ms defaulting to 10ms to provide previous behavior. Also cleos commands get table, get table scope, and get_producers now take a --time-limit which allows for overriding the default 10ms limit. This time limit will be used as before to limit the returned output. Note the nodeos configured http-max-response-time-ms will take precedence and hard fail any http request taking longer than http-max-response-time-ms . Also --time-limit will be ignored by any nodeos that does not have these PR changes.

Example cleos:

./cleos system listproducers --help
List producers
Usage: ./cleos system listproducers [OPTIONS]

Options:
  -h,--help                   Print this help message and exit
  -j,--json                   Output in JSON format
  -l,--limit UINT             The maximum number of rows to return
  -L,--lower TEXT             Lower bound value of key, defaults to first
  --time-limit UINT           Limit time of execution in milliseconds, defaults to 10ms

This enables setting http-max-response-time-ms to -1 on a local nodeos and specifying --limit 999999 --time-limit 999999 to cleos get table allowing users to retrieve complete table output without multiple calls to get table. Note this will block the main thread during the complete call.

Resolves eosnetworkfoundation/mandel#819

[matthewdarwin]

A block production node should not enable the chain_api_plugin as these limits can interfere with block production windows.

As far as I know, there is no practical way to monitor a node other than enabling chain_api_plugin to run /v1/chain/get_info requests, even on a producing node. Of course get_info returns very quickly, so not an issue related to this change. Just commenting on the part of "no enable the chain api".