Merge pull request #4755 from carlaKC/4669-nonlockedcall

multi: use bitcoind uptime api for healthcheck
This commit is contained in:
Olaoluwa Osuntokun 2020-11-11 17:47:51 -08:00 committed by GitHub
commit 05592ad3ba
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2 changed files with 73 additions and 4 deletions

@ -2,6 +2,7 @@ package chainreg
import (
"encoding/hex"
"encoding/json"
"errors"
"fmt"
"io/ioutil"
@ -177,6 +178,11 @@ type ChainControl struct {
// ChainIO represents an abstraction over a source that can query the blockchain.
ChainIO lnwallet.BlockChainIO
// HealthCheck is a function which can be used to send a low-cost, fast
// query to the chain backend to ensure we still have access to our
// node.
HealthCheck func() error
// FeeEstimator is used to estimate an optimal fee for transactions important to us.
FeeEstimator chainfee.Estimator
@ -318,6 +324,12 @@ func NewChainControl(cfg *Config) (*ChainControl, error) {
cfg.ActiveNetParams.Params, cfg.NeutrinoCS,
)
// Get our best block as a health check.
cc.HealthCheck = func() error {
_, _, err := walletConfig.ChainSource.GetBestBlock()
return err
}
case "bitcoind", "litecoind":
var bitcoindMode *lncfg.Bitcoind
switch {
@ -431,6 +443,27 @@ func NewChainControl(cfg *Config) (*ChainControl, error) {
return nil, err
}
}
// We need to use some apis that are not exposed by btcwallet,
// for a health check function so we create an ad-hoc bitcoind
// connection.
chainConn, err := rpcclient.New(rpcConfig, nil)
if err != nil {
return nil, err
}
// The api we will use for our health check depends on the
// bitcoind version.
cmd, err := getBitcoindHealthCheckCmd(chainConn)
if err != nil {
return nil, err
}
cc.HealthCheck = func() error {
_, err := chainConn.RawRequest(cmd, nil)
return err
}
case "btcd", "ltcd":
// Otherwise, we'll be speaking directly via RPC to a node.
//
@ -514,6 +547,12 @@ func NewChainControl(cfg *Config) (*ChainControl, error) {
walletConfig.ChainSource = chainRPC
// Use a query for our best block as a health check.
cc.HealthCheck = func() error {
_, _, err := walletConfig.ChainSource.GetBestBlock()
return err
}
// If we're not in simnet or regtest mode, then we'll attempt
// to use a proper fee estimator for testnet.
if !cfg.Bitcoin.SimNet && !cfg.Litecoin.SimNet &&
@ -612,6 +651,39 @@ func NewChainControl(cfg *Config) (*ChainControl, error) {
return cc, nil
}
// getBitcoindHealthCheckCmd queries bitcoind for its version to decide which
// api we should use for our health check. We prefer to use the uptime
// command, because it has no locking and is an inexpensive call, which was
// added in version 0.15. If we are on an earlier version, we fallback to using
// getblockchaininfo.
func getBitcoindHealthCheckCmd(client *rpcclient.Client) (string, error) {
// Query bitcoind to get our current version.
resp, err := client.RawRequest("getnetworkinfo", nil)
if err != nil {
return "", err
}
// Parse the response to retrieve bitcoind's version.
info := struct {
Version int64 `json:"version"`
}{}
if err := json.Unmarshal(resp, &info); err != nil {
return "", err
}
// Bitcoind returns a single value representing the semantic version:
// 1000000 * CLIENT_VERSION_MAJOR + 10000 * CLIENT_VERSION_MINOR
// + 100 * CLIENT_VERSION_REVISION + 1 * CLIENT_VERSION_BUILD
//
// The uptime call was added in version 0.15.0, so we return it for
// any version value >= 150000, as per the above calculation.
if info.Version >= 150000 {
return "uptime", nil
}
return "getblockchaininfo", nil
}
var (
// BitcoinTestnetGenesis is the genesis hash of Bitcoin's testnet
// chain.

@ -1292,10 +1292,7 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
// will not run it.
chainHealthCheck := healthcheck.NewObservation(
"chain backend",
func() error {
_, _, err := cc.ChainIO.GetBestBlock()
return err
},
cc.HealthCheck,
cfg.HealthChecks.ChainCheck.Interval,
cfg.HealthChecks.ChainCheck.Timeout,
cfg.HealthChecks.ChainCheck.Backoff,