github.com/onflow/flow-go@v0.35.7-crescendo-preview.23-atree-inlining/module/dkg/controller_factory.go (about)

     1  package dkg
     2  
     3  import (
     4  	"fmt"
     5  
     6  	"github.com/onflow/crypto"
     7  	"github.com/rs/zerolog"
     8  
     9  	"github.com/onflow/flow-go/model/flow"
    10  	"github.com/onflow/flow-go/module"
    11  	"github.com/onflow/flow-go/module/signature"
    12  )
    13  
    14  // ControllerFactory is a factory object that creates new Controllers for new
    15  // epochs. Each Controller produced by a factory shares the same underlying
    16  // Local object to sign broadcast messages, the same tunnel tying it to the
    17  // MessagingEngine, and the same client to communicate with the DKG
    18  // smart-contract.
    19  type ControllerFactory struct {
    20  	log                zerolog.Logger
    21  	me                 module.Local
    22  	dkgContractClients []module.DKGContractClient
    23  	tunnel             *BrokerTunnel
    24  }
    25  
    26  // NewControllerFactory creates a new factory that generates Controllers with
    27  // the same underlying Local object, tunnel and dkg smart-contract client.
    28  func NewControllerFactory(
    29  	log zerolog.Logger,
    30  	me module.Local,
    31  	dkgContractClients []module.DKGContractClient,
    32  	tunnel *BrokerTunnel,
    33  ) *ControllerFactory {
    34  
    35  	return &ControllerFactory{
    36  		log:                log,
    37  		me:                 me,
    38  		dkgContractClients: dkgContractClients,
    39  		tunnel:             tunnel,
    40  	}
    41  }
    42  
    43  // Create creates a new epoch-specific Controller equipped with a broker which
    44  // is capable of communicating with other nodes.
    45  func (f *ControllerFactory) Create(
    46  	dkgInstanceID string,
    47  	participants flow.IdentitySkeletonList,
    48  	seed []byte) (module.DKGController, error) {
    49  
    50  	myIndex, ok := participants.GetIndex(f.me.NodeID())
    51  	if !ok {
    52  		return nil, fmt.Errorf("failed to create controller factory, node %s is not part of DKG committee", f.me.NodeID().String())
    53  	}
    54  
    55  	broker := NewBroker(
    56  		f.log,
    57  		dkgInstanceID,
    58  		participants,
    59  		f.me,
    60  		int(myIndex),
    61  		f.dkgContractClients,
    62  		f.tunnel,
    63  	)
    64  
    65  	n := len(participants)
    66  	threshold := signature.RandomBeaconThreshold(n)
    67  	dkg, err := crypto.NewJointFeldman(n, threshold, int(myIndex), broker)
    68  	if err != nil {
    69  		return nil, err
    70  	}
    71  
    72  	controller := NewController(
    73  		f.log,
    74  		dkgInstanceID,
    75  		dkg,
    76  		seed,
    77  		broker,
    78  	)
    79  
    80  	return controller, nil
    81  }