* limit number of /subscribe clients and queries per client

Add the following config variables (under [rpc] section):
  * max_subscription_clients
  * max_subscriptions_per_client
  * timeout_broadcast_tx_commit

Fixes #2826

new HTTPClient interface for subscriptions

finalize HTTPClient events interface

remove EventSubscriber

fix data race

```
WARNING: DATA RACE
Read at 0x00c000a36060 by goroutine 129:
  github.com/tendermint/tendermint/rpc/client.(*Local).Subscribe.func1()
      /go/src/github.com/tendermint/tendermint/rpc/client/localclient.go:168 +0x1f0

Previous write at 0x00c000a36060 by goroutine 132:
  github.com/tendermint/tendermint/rpc/client.(*Local).Subscribe()
      /go/src/github.com/tendermint/tendermint/rpc/client/localclient.go:191 +0x4e0
  github.com/tendermint/tendermint/rpc/client.WaitForOneEvent()
      /go/src/github.com/tendermint/tendermint/rpc/client/helpers.go:64 +0x178
  github.com/tendermint/tendermint/rpc/client_test.TestTxEventsSentWithBroadcastTxSync.func1()
      /go/src/github.com/tendermint/tendermint/rpc/client/event_test.go:139 +0x298
  testing.tRunner()
      /usr/local/go/src/testing/testing.go:827 +0x162

Goroutine 129 (running) created at:
  github.com/tendermint/tendermint/rpc/client.(*Local).Subscribe()
      /go/src/github.com/tendermint/tendermint/rpc/client/localclient.go:164 +0x4b7
  github.com/tendermint/tendermint/rpc/client.WaitForOneEvent()
      /go/src/github.com/tendermint/tendermint/rpc/client/helpers.go:64 +0x178
  github.com/tendermint/tendermint/rpc/client_test.TestTxEventsSentWithBroadcastTxSync.func1()
      /go/src/github.com/tendermint/tendermint/rpc/client/event_test.go:139 +0x298
  testing.tRunner()
      /usr/local/go/src/testing/testing.go:827 +0x162

Goroutine 132 (running) created at:
  testing.(*T).Run()
      /usr/local/go/src/testing/testing.go:878 +0x659
  github.com/tendermint/tendermint/rpc/client_test.TestTxEventsSentWithBroadcastTxSync()
      /go/src/github.com/tendermint/tendermint/rpc/client/event_test.go:119 +0x186
  testing.tRunner()
      /usr/local/go/src/testing/testing.go:827 +0x162
==================
```

lite client works (tested manually)

godoc comments

httpclient: do not close the out channel

use TimeoutBroadcastTxCommit

no timeout for unsubscribe

but 1s Local (5s HTTP) timeout for resubscribe

format code

change Subscribe#out cap to 1

and replace config vars with RPCConfig

TimeoutBroadcastTxCommit can't be greater than rpcserver.WriteTimeout

rpc: Context as first parameter to all functions

reformat code

fixes after my own review

fixes after Ethan's review

add test stubs

fix config.toml

* fixes after manual testing

- rpc: do not recommend to use BroadcastTxCommit because it's slow and wastes
Tendermint resources (pubsub)
- rpc: better error in Subscribe and BroadcastTxCommit
- HTTPClient: do not resubscribe if err = ErrAlreadySubscribed

* fixes after Ismail's review

* Update rpc/grpc/grpc_test.go

Co-Authored-By: melekes <anton.kalyaev@gmail.com>

* green pubsub tests :OK:

* get rid of clientToQueryMap

* Subscribe and SubscribeUnbuffered

* start adapting other pkgs to new pubsub

* nope

* rename MsgAndTags to Message

* remove TagMap

it does not bring any additional benefits

* bring back EventSubscriber

* fix test

* fix data race in TestStartNextHeightCorrectly

```
Write at 0x00c0001c7418 by goroutine 796:
  github.com/tendermint/tendermint/consensus.TestStartNextHeightCorrectly()
      /go/src/github.com/tendermint/tendermint/consensus/state_test.go:1296 +0xad
  testing.tRunner()
      /usr/local/go/src/testing/testing.go:827 +0x162

Previous read at 0x00c0001c7418 by goroutine 858:
  github.com/tendermint/tendermint/consensus.(*ConsensusState).addVote()
      /go/src/github.com/tendermint/tendermint/consensus/state.go:1631 +0x1366
  github.com/tendermint/tendermint/consensus.(*ConsensusState).tryAddVote()
      /go/src/github.com/tendermint/tendermint/consensus/state.go:1476 +0x8f
  github.com/tendermint/tendermint/consensus.(*ConsensusState).handleMsg()
      /go/src/github.com/tendermint/tendermint/consensus/state.go:667 +0xa1e
  github.com/tendermint/tendermint/consensus.(*ConsensusState).receiveRoutine()
      /go/src/github.com/tendermint/tendermint/consensus/state.go:628 +0x794

Goroutine 796 (running) created at:
  testing.(*T).Run()
      /usr/local/go/src/testing/testing.go:878 +0x659
  testing.runTests.func1()
      /usr/local/go/src/testing/testing.go:1119 +0xa8
  testing.tRunner()
      /usr/local/go/src/testing/testing.go:827 +0x162
  testing.runTests()
      /usr/local/go/src/testing/testing.go:1117 +0x4ee
  testing.(*M).Run()
      /usr/local/go/src/testing/testing.go:1034 +0x2ee
  main.main()
      _testmain.go:214 +0x332

Goroutine 858 (running) created at:
  github.com/tendermint/tendermint/consensus.(*ConsensusState).startRoutines()
      /go/src/github.com/tendermint/tendermint/consensus/state.go:334 +0x221
  github.com/tendermint/tendermint/consensus.startTestRound()
      /go/src/github.com/tendermint/tendermint/consensus/common_test.go:122 +0x63
  github.com/tendermint/tendermint/consensus.TestStateFullRound1()
      /go/src/github.com/tendermint/tendermint/consensus/state_test.go:255 +0x397
  testing.tRunner()
      /usr/local/go/src/testing/testing.go:827 +0x162
```

* fixes after my own review

* fix formatting

* wait 100ms before kicking a subscriber out

+ a test for indexer_service

* fixes after my second review

* no timeout

* add changelog entries

* fix merge conflicts

* fix typos after Thane's review

Co-Authored-By: melekes <anton.kalyaev@gmail.com>

* reformat code

* rewrite indexer service in the attempt to fix failing test

https://github.com/tendermint/tendermint/pull/3227/#issuecomment-462316527

* Revert "rewrite indexer service in the attempt to fix failing test"

This reverts commit 0d9107a098.

* another attempt to fix indexer

* fixes after Ethan's review

* use unbuffered channel when indexing transactions

Refs https://github.com/tendermint/tendermint/pull/3227#discussion_r258786716

* add a comment for EventBus#SubscribeUnbuffered

* format code

As per conversation here: https://github.com/tendermint/tendermint/pull/3218#discussion_r251364041

This is the result of running the following code on the repo:

```bash
find . -name '*.go' | grep -v 'vendor/' | xargs -n 1 goimports -w
```

* Fixed accepting integer IDs in requests for Tendermint RPC server (#2366)

* added a wrapper interface `jsonrpcid` that represents both string and int IDs in JSON-RPC requests/responses + custom JSON unmarshallers

* changed client-side code in RPC that uses it

* added extra tests for integer IDs

* updated CHANGELOG_PENDING, as suggested by PR instructions

* addressed PR comments

* added table driven tests for request type marshalling/unmarshalling
* expanded handler test to check IDs
* changed pending changelog note

* changed json rpc request/response unmarshalling to use empty interfaces and type switches on ID

* some cleanup

This reverts commit d02c5d1e30.

This reverts commit 96a3502

Refs #951

Jae: I don't know a good way to catch these errors in general, but
forcing pubsub's internal channel to have a capacity of 0 will reveal
bugs sooner, if the subscriber also has a 0 or small capacity ch to pull
from.

Refs #847

* use increment and decrement operators.

* remove unnecessary else branches.

* fix package comment with leading space.

* fix receiver names.

* fix error strings.

* remove omittable code.

* remove redundant return statement.

* Revert changes (code is generated.)

* use cfg as receiver name for all config-related types.

* use lsi as the receiver name for the LastSignedInfo type.

comment out failing consensus tests for now

rewrite rpc httpclient to use new pubsub package

import pubsub as tmpubsub, query as tmquery

make event IDs constants
EventKey -> EventTypeKey

rename EventsPubsub to PubSub

mempool does not use pubsub

rename eventsSub to pubsub

new subscribe API

fix channel size issues and consensus tests bugs

refactor rpc client

add missing discardFromChan method

add mutex

rename pubsub to eventBus

remove IsRunning from WSRPCConnection interface (not needed)

add a comment in broadcastNewRoundStepsAndVotes

rename registerEventCallbacks to broadcastNewRoundStepsAndVotes

See https://dave.cheney.net/2014/03/19/channel-axioms

stop eventBuses after reactor tests

remove unnecessary Unsubscribe

return subscribe helper function

move discardFromChan to where it is used

subscribe now returns an err

this gives us ability to refuse to subscribe if pubsub is at its max
capacity.

use context for control overflow

cache queries

handle err when subscribing in replay_test

rename testClientID to testSubscriber

extract var

set channel buffer capacity to 1 in replay_file

fix byzantine_test

unsubscribe from single event, not all events

refactor httpclient to return events to appropriate channels

return failing testReplayCrashBeforeWriteVote test

fix TestValidatorSetChanges

refactor code a bit

fix testReplayCrashBeforeWriteVote

add comment

fix TestValidatorSetChanges

fixes from Bucky's review

update comment [ci skip]

test TxEventBuffer

update changelog

fix TestValidatorSetChanges (2nd attempt)

only do wg.Done when no errors

benchmark event bus

create pubsub server inside NewEventBus

only expose config params (later if needed)

set buffer capacity to 0 so we are not testing cache

new tx event format: key = "Tx" plus a tag {"tx.hash": XYZ}

This should allow to subscribe to all transactions! or a specific one
using a query: "tm.events.type = Tx and tx.hash = '013ABF99434...'"

use TimeoutCommit instead of afterPublishEventNewBlockTimeout

TimeoutCommit is the time a node waits after committing a block, before
it goes into the next height. So it will finish everything from the last
block, but then wait a bit. The idea is this gives it time to hear more
votes from other validators, to strengthen the commit it includes in the
next block. But it also gives it time to hear about new transactions.

waitForBlockWithUpdatedVals

rewrite WAL crash tests

Task:
test that we can recover from any WAL crash.

Solution:
the old tests were relying on event hub being run in the same thread (we
were injecting the private validator's last signature).

when considering a rewrite, we considered two possible solutions: write
a "fuzzy" testing system where WAL is crashing upon receiving a new
message, or inject failures and trigger them in tests using something
like https://github.com/coreos/gofail.

remove sleep

no cs.Lock around wal.Save

test different cases (empty block, non-empty block, ...)

comments

add comments

test 4 cases: empty block, non-empty block, non-empty block with smaller part size, many blocks

fixes as per Bucky's last review

reset subscriptions on UnsubscribeAll

use a simple counter to track message for which we panicked

also, set a smaller part size for all test cases

https://github.com/tendermint/tendermint/pull/724#issuecomment-335362927

from the spec:
This member is REQUIRED.
It MUST be the same as the value of the id member in the Request Object.
If there was an error in detecting the id in the Request object (e.g. Parse error/Invalid Request), it MUST be Null.

```
data
A Primitive or Structured value that contains additional information about the error.
This may be omitted.
The value of this member is defined by the Server (e.g. detailed error information, nested errors etc.).
```

What's new:
- auto reconnect
- ping/pong
- colored tests