rpcserver: implement the getblockchaininfo RPC call

glide.lock

@@ -1,10 +1,10 @@
 hash: 8f89ba1940f8798b8a0449810532e3f0bc552ed97d907bc3447a8941a2ea3a4a
-updated: 2016-10-26T22:53:00.0848822-05:00
+updated: 2016-11-11T17:21:09.070085014-08:00
 imports:
 - name: github.com/btcsuite/btclog
   version: 73889fb79bd687870312b6e40effcecffbd57d30
 - name: github.com/btcsuite/btcrpcclient
-  version: 2b780d16b042054d07aa322146194118fd7f7b81
+  version: c6e1d711da0db56803309479a5deabb02b816e88
 - name: github.com/btcsuite/btcutil
   version: aa9087a7efc961fbd253d4ae9c8b7a318749c273
   subpackages:

rpcserver.go

@@ -144,6 +144,7 @@ var rpcHandlersBeforeInit = map[string]commandHandler{
 	"getbestblock":          handleGetBestBlock,
 	"getbestblockhash":      handleGetBestBlockHash,
 	"getblock":              handleGetBlock,
+	"getblockchaininfo":     handleGetBlockChainInfo,
 	"getblockcount":         handleGetBlockCount,
 	"getblockhash":          handleGetBlockHash,
 	"getblockheader":        handleGetBlockHeader,
@@ -228,7 +229,6 @@ var rpcAskWallet = map[string]struct{}{
 var rpcUnimplemented = map[string]struct{}{
 	"estimatefee":      {},
 	"estimatepriority": {},
-	"getblockchaininfo": {},
 	"getchaintips":     {},
 	"getnetworkinfo":   {},
 	"invalidateblock":  {},
@@ -1121,6 +1121,127 @@ func handleGetBlock(s *rpcServer, cmd interface{}, closeChan <-chan struct{}) (i
 	return blockReply, nil
 }
 
+// softForkStatus converts a ThresholdState state into a human readable string
+// corresponding to the particular state.
+func softForkStatus(state blockchain.ThresholdState) (string, error) {
+	switch state {
+	case blockchain.ThresholdDefined:
+		return "defined", nil
+	case blockchain.ThresholdStarted:
+		return "started", nil
+	case blockchain.ThresholdLockedIn:
+		return "lockedin", nil
+	case blockchain.ThresholdActive:
+		return "active", nil
+	case blockchain.ThresholdFailed:
+		return "failed", nil
+	default:
+		return "", fmt.Errorf("unknown deployment state: %v", state)
+	}
+}
+
+// handleGetBlockChainInfo implements the getblockchaininfo command.
+func handleGetBlockChainInfo(s *rpcServer, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
+
+	// Obtain a snapshot of the current best known blockchain state. We'll
+	// populate the response to this call primarily from this snapshot.
+	chainSnapshot := s.chain.BestSnapshot()
+
+	chainInfo := &btcjson.GetBlockChainInfoResult{
+		Chain:         activeNetParams.Name,
+		Blocks:        chainSnapshot.Height,
+		Headers:       chainSnapshot.Height,
+		BestBlockHash: chainSnapshot.Hash.String(),
+		Difficulty:    getDifficultyRatio(chainSnapshot.Bits),
+		MedianTime:    chainSnapshot.MedianTime.Unix(),
+		Pruned:        false,
+		Bip9SoftForks: make(map[string]*btcjson.Bip9SoftForkDescription),
+	}
+
+	// Next, populate the response with information describing the current
+	// status of soft-forks deployed via the super-majority block
+	// signalling mechanism.
+	height := chainSnapshot.Height
+	chainInfo.SoftForks = []*btcjson.SoftForkDescription{
+		{
+			ID:      "bip34",
+			Version: 2,
+			Reject: struct {
+				Status bool `json:"status"`
+			}{
+				Status: height >= activeNetParams.BIP0034Height,
+			},
+		},
+		{
+			ID:      "bip66",
+			Version: 3,
+			Reject: struct {
+				Status bool `json:"status"`
+			}{
+				Status: height >= activeNetParams.BIP0066Height,
+			},
+		},
+		{
+			ID:      "bip65",
+			Version: 4,
+			Reject: struct {
+				Status bool `json:"status"`
+			}{
+				Status: height >= activeNetParams.BIP0065Height,
+			},
+		},
+	}
+
+	// Finally, query the BIP0009 version bits state for all currently
+	// defined BIP0009 soft-fork deployments.
+	for deployment, deploymentDetails := range activeNetParams.Deployments {
+		// Map the integer deployment ID into a human readable
+		// fork-name.
+		var forkName string
+		switch deployment {
+		case chaincfg.DeploymentTestDummy:
+			forkName = "dummy"
+		default:
+			return nil, &btcjson.RPCError{
+				Code: btcjson.ErrRPCInternal.Code,
+				Message: fmt.Sprintf("Unknown deployment %v "+
+					"detected", deployment),
+			}
+		}
+
+		// Query the chain for the current status of the deployment as
+		// identified by its deployment ID.
+		deploymentStatus, err := s.chain.ThresholdState(uint32(deployment))
+		if err != nil {
+			context := "Failed to obtain deployment status"
+			return nil, internalRPCError(err.Error(), context)
+		}
+
+		// Attempt to convert the current deployment status into a
+		// human readable string. If the status is unrecognized, then a
+		// non-nil error is returned.
+		statusString, err := softForkStatus(deploymentStatus)
+		if err != nil {
+			return nil, &btcjson.RPCError{
+				Code: btcjson.ErrRPCInternal.Code,
+				Message: fmt.Sprintf("unknown deployment status: %v",
+					deploymentStatus),
+			}
+		}
+
+		// Finally, populate the soft-fork description with all the
+		// information gathered above.
+		chainInfo.Bip9SoftForks[forkName] = &btcjson.Bip9SoftForkDescription{
+			Status:    strings.ToLower(statusString),
+			Bit:       deploymentDetails.BitNumber,
+			StartTime: int64(deploymentDetails.StartTime),
+			Timeout:   int64(deploymentDetails.ExpireTime),
+		}
+	}
+
+	return chainInfo, nil
+}
+
 // handleGetBlockCount implements the getblockcount command.
 func handleGetBlockCount(s *rpcServer, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
 	best := s.chain.BestSnapshot()

rpcserverhelp.go

@@ -156,6 +156,32 @@ var helpDescsEnUS = map[string]string{
 	"getblock--condition1": "verbose=true",
 	"getblock--result0":    "Hex-encoded bytes of the serialized block",
 
+	// GetBlockChainInfoCmd help.
+	"getblockchaininfo--synopsis": "Returns information about the current blockchain state and the status of any active soft-fork deployments.",
+
+	// GetBlockChainInfoResult help.
+	"getblockchaininforesult-chain":                 "The name of the chain the daemon is on (testnet, mainnet, etc)",
+	"getblockchaininforesult-blocks":                "The number of blocks in the best known chain",
+	"getblockchaininforesult-headers":               "The number of headers that we've gathered for in the best known chain",
+	"getblockchaininforesult-bestblockhash":         "The block hash for the latest block in the main chain",
+	"getblockchaininforesult-difficulty":            "The current chain difficulty",
+	"getblockchaininforesult-mediantime":            "The median time from the PoV of the best block in the chain",
+	"getblockchaininforesult-verificationprogress":  "An estimate for how much of the best chain we've verified",
+	"getblockchaininforesult-pruned":                "A bool that indicates if the node is pruned or not",
+	"getblockchaininforesult-pruneheight":           "The lowest block retained in the current pruned chain",
+	"getblockchaininforesult-chainwork":             "The total cumulative work in the best chain",
+	"getblockchaininforesult-softforks":             "The status of the super-majority soft-forks",
+	"getblockchaininforesult-bip9_softforks":        "JSON object describing active BIP0009 deployments",
+	"getblockchaininforesult-bip9_softforks--key":   "bip9_softforks",
+	"getblockchaininforesult-bip9_softforks--value": "An object describing a particular BIP009 deployment",
+	"getblockchaininforesult-bip9_softforks--desc":  "The status of any defined BIP0009 soft-fork deployments",
+
+	// SoftForkDescription help.
+	"softforkdescription-reject":  "The current activation status of the softfork",
+	"softforkdescription-version": "The block version that signals enforcement of this softfork",
+	"softforkdescription-id":      "The string identifier for the soft fork",
+	"-status":                     "A bool which indicates if the soft fork is active",
+
 	// TxRawResult help.
 	"txrawresult-hex":           "Hex-encoded transaction",
 	"txrawresult-txid":          "The hash of the transaction",
@@ -599,6 +625,7 @@ var rpcResultTypes = map[string][]interface{}{
 	"getblockhash":          {(*string)(nil)},
 	"getblockheader":        {(*string)(nil), (*btcjson.GetBlockHeaderVerboseResult)(nil)},
 	"getblocktemplate":      {(*btcjson.GetBlockTemplateResult)(nil), (*string)(nil), nil},
+	"getblockchaininfo":     {(*btcjson.GetBlockChainInfoResult)(nil)},
 	"getconnectioncount":    {(*int32)(nil)},
 	"getcurrentnet":         {(*uint32)(nil)},
 	"getdifficulty":         {(*float64)(nil)},