BFT Block Puller: BFTDeliverer (#4365)

* BFT Block Puller: censorship monitor

BFT header receivers that pull headers from the orderers, and keep the time and number of the last one.
The header receivers verify each block as it arrives.
The header receivers will receive (or ask for) full config blocks - in a later commit.
The header receivers will maintain their own private block verifier (bundle) - in a later commit.

A BFT censorship monitor which periodically compares the progress of headers relative to blocks.
The monitor triggers an alert if a header is ahead of the block stream for more than a certain time.

The BFTDeliverer is only a skeleton

Signed-off-by: Yoav Tock <tock@il.ibm.com>
Change-Id: I5180a98640073b87effb478fd86b6fa7d4df5dee

* BFT Block Puller: BFTDeliverer

- A BFTDeliverer that fetches blocks and maintains a BFTCensorshipMonitor.
- Abstract the creation of a BFTCensorshipMonitor via an abstract factory, so that we can use a mock for it in testing.
- Add a "shuffledEndpoints" method to the connection source and test it.
- Unit testing of BFTDeliverer.

Signed-off-by: Yoav Tock <tock@il.ibm.com>
Change-Id: Ifead3f9e6c803c4d9fabc63acce11c6da472b88d

---------

Signed-off-by: Yoav Tock <tock@il.ibm.com>

internal/pkg/peer/blocksprovider/bft_censorship_monitor_factory.go

@@ -0,0 +1,25 @@
+/*
+Copyright IBM Corp. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package blocksprovider
+
+import "github.com/hyperledger/fabric/internal/pkg/peer/orderers"
+
+// BFTCensorshipMonitorFactory creates an instance of a BFTCensorshipMonitor. It is an implementation of the
+// CensorshipDetectorFactory interface which abstracts the creation of a BFTCensorshipMonitor.
+type BFTCensorshipMonitorFactory struct{}
+
+func (f *BFTCensorshipMonitorFactory) Create(
+	chainID string,
+	verifier BlockVerifier,
+	requester DeliverClientRequester,
+	progressReporter BlockProgressReporter,
+	fetchSources []*orderers.Endpoint,
+	blockSourceIndex int,
+	timeoutConf TimeoutConfig,
+) CensorshipDetector {
+	return NewBFTCensorshipMonitor(chainID, verifier, requester, progressReporter, fetchSources, blockSourceIndex, timeoutConf)
+}

internal/pkg/peer/blocksprovider/bft_censorship_monitor_factory_test.go

@@ -0,0 +1,21 @@
+/*
+Copyright IBM Corp. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package blocksprovider_test
+
+import (
+	"testing"
+
+	"github.com/hyperledger/fabric/internal/pkg/peer/blocksprovider"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNewBFTCensorshipMonitorFactory(t *testing.T) {
+	s := newMonitorTestSetup(t, 5)
+	f := &blocksprovider.BFTCensorshipMonitorFactory{}
+	mon := f.Create(s.channelID, s.fakeBlockVerifier, s.fakeRequester, s.fakeProgressReporter, s.sources, 0, blocksprovider.TimeoutConfig{})
+	require.NotNil(t, mon)
+}