Add \health rpc endpoint (#1306)

* Init `\health` rpc endpoint

* remove additional info from `\health` rpc endpoint

* Cleanup imports

* Added time threshold for health check

* Update rpc doc

* Remove unnecessary checks for blocktime creation lag

* Clean up of unnecessary config usage

.gitignore

@@ -21,3 +21,6 @@ docs/tools
 
 scripts/wal2json/wal2json
 scripts/cutWALUntil/cutWALUntil
+
+.idea/
+*.iml

docs/specification/rpc.rst

@@ -97,6 +97,7 @@ An HTTP Get request to the root RPC endpoint (e.g.
     http://localhost:46657/genesis
     http://localhost:46657/net_info
     http://localhost:46657/num_unconfirmed_txs
+    http://localhost:46657/health
     http://localhost:46657/status
     http://localhost:46657/unconfirmed_txs
     http://localhost:46657/unsafe_flush_mempool

rpc/core/doc.go

@@ -81,6 +81,7 @@ Available endpoints:
 /net_info
 /num_unconfirmed_txs
 /status
+/health
 /unconfirmed_txs
 /unsafe_flush_mempool
 /unsafe_stop_cpu_profiler

rpc/core/health.go

@@ -0,0 +1,30 @@
+package core
+
+import (
+	ctypes "github.com/tendermint/tendermint/rpc/core/types"
+)
+
+// Get node health. Checks whether new blocks are created.
+//
+// ```shell
+// curl 'localhost:46657/health'
+// ```
+//
+// ```go
+// client := client.NewHTTP("tcp://0.0.0.0:46657", "/websocket")
+// result, err := client.Health()
+// ```
+//
+// > The above command returns JSON structured like this:
+//
+// ```json
+// {
+// 	"error": "",
+// 	"result": {},
+// 	"id": "",
+// 	"jsonrpc": "2.0"
+// }
+// ```
+func Health() (*ctypes.ResultHealth, error) {
+	return &ctypes.ResultHealth{}, nil
+}

rpc/core/pipe.go

@@ -3,10 +3,10 @@ package core
 import (
 	"time"
 
-	crypto "github.com/tendermint/go-crypto"
+	"github.com/tendermint/go-crypto"
 	"github.com/tendermint/tendermint/consensus"
 	cstypes "github.com/tendermint/tendermint/consensus/types"
-	p2p "github.com/tendermint/tendermint/p2p"
+	"github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/proxy"
 	sm "github.com/tendermint/tendermint/state"
 	"github.com/tendermint/tendermint/state/txindex"

rpc/core/routes.go

@@ -12,6 +12,7 @@ var Routes = map[string]*rpc.RPCFunc{
 	"unsubscribe_all": rpc.NewWSRPCFunc(UnsubscribeAll, ""),
 
 	// info API
+	"health":               rpc.NewRPCFunc(Health, ""),
 	"status":               rpc.NewRPCFunc(Status, ""),
 	"net_info":             rpc.NewRPCFunc(NetInfo, ""),
 	"blockchain":           rpc.NewRPCFunc(BlockchainInfo, "minHeight,maxHeight"),

rpc/core/types/responses.go

@@ -155,3 +155,5 @@ type ResultEvent struct {
 	Query string            `json:"query"`
 	Data  types.TMEventData `json:"data"`
 }
+
+type ResultHealth struct{}

types/heartbeat.go

@@ -14,7 +14,7 @@ import (
 // json field tags because we always want the JSON
 // representation to be in its canonical form.
 type Heartbeat struct {
-	ValidatorAddress Address   `json:"validator_address"`
+	ValidatorAddress Address          `json:"validator_address"`
 	ValidatorIndex   int              `json:"validator_index"`
 	Height           int64            `json:"height"`
 	Round            int              `json:"round"`