rpc: verify wallet version (#42)

go.mod

@@ -3,7 +3,7 @@ module github.com/jholdstock/dcrvsp
 go 1.13
 
 require (
-	decred.org/dcrwallet v1.2.3-0.20200507155221-397dd551e317
+	decred.org/dcrwallet v1.2.3-0.20200519180100-f1aa4c354e05
 	github.com/decred/dcrd/blockchain/stake/v3 v3.0.0-20200511175520-d08cb3f72b3b
 	github.com/decred/dcrd/chaincfg/chainhash v1.0.2
 	github.com/decred/dcrd/chaincfg/v3 v3.0.0-20200511175520-d08cb3f72b3b

go.sum

@@ -1,7 +1,7 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 decred.org/cspp v0.3.0/go.mod h1:UygjYilC94dER3BEU65Zzyoqy9ngJfWCD2rdJqvUs2A=
-decred.org/dcrwallet v1.2.3-0.20200507155221-397dd551e317 h1:j1fUXpVowoLVVFlaJO7bibK4aSPeQa0EF+nPFuy76Hg=
+decred.org/dcrwallet v1.2.3-0.20200519180100-f1aa4c354e05 h1:xongFmW2UgEOGu4zQ4VcQFduExKVBa+dC4aLRQLCCnQ=
-decred.org/dcrwallet v1.2.3-0.20200507155221-397dd551e317/go.mod h1:V6pzOHJuuWZaUPUZZL2kiyx9Co3lVD0DRqDXJTWA+3c=
+decred.org/dcrwallet v1.2.3-0.20200519180100-f1aa4c354e05/go.mod h1:V6pzOHJuuWZaUPUZZL2kiyx9Co3lVD0DRqDXJTWA+3c=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/agl/ed25519 v0.0.0-20170116200512-5312a6153412 h1:w1UutsfOrms1J05zt7ISrnJIXKzwaspym5BTKGx93EI=
 github.com/agl/ed25519 v0.0.0-20170116200512-5312a6153412/go.mod h1:WPjqKcmVOxf0XSf3YxCJs6N6AOSrOx3obionmG7T0y0=

rpc/client.go

@@ -4,13 +4,20 @@ import (
 	"context"
 	"crypto/tls"
 	"crypto/x509"
+	"fmt"
 	"sync"
 
+	wallettypes "decred.org/dcrwallet/rpc/jsonrpc/types"
+	dcrdtypes "github.com/decred/dcrd/rpc/jsonrpc/types/v2"
 	"github.com/jrick/wsrpc/v2"
 )
 
 type Client func() (*wsrpc.Client, error)
 
+const (
+	requiredWalletVersion = "8.1.0"
+)
+
 // Setup accepts RPC connection details, creates an RPC client, and returns a
 // function which can be called to access the client. The returned function will
 // try to handle any client disconnects by attempting to reconnect, but will
@@ -72,6 +79,40 @@ func Setup(ctx context.Context, shutdownWg *sync.WaitGroup, user, pass, addr str
 			return nil, err
 		}
 		log.Infof("Dialed RPC websocket %v", addr)
+
+		// Verify dcrwallet at is at the required api version
+		var verMap map[string]dcrdtypes.VersionResult
+		err = c.Call(ctx, "version", &verMap)
+		if err != nil {
+			c.Close()
+			return nil, fmt.Errorf("wallet %v version failed: %v",
+				addr, err)
+		}
+		walletVersion, exists := verMap["dcrwalletjsonrpcapi"]
+		if !exists {
+			c.Close()
+			return nil, fmt.Errorf("wallet %v version response "+
+				"missing 'dcrwalletjsonrpcapi'", addr)
+		}
+		if walletVersion.VersionString != requiredWalletVersion {
+			c.Close()
+			return nil, fmt.Errorf("wallet %v is not at the "+
+				"proper version: %s != %s", addr,
+				walletVersion.VersionString, requiredWalletVersion)
+		}
+
+		// Verify dcrwallet is voting
+		var walletInfo wallettypes.WalletInfoResult
+		err = c.Call(ctx, "walletinfo", &walletInfo)
+		if err != nil {
+			c.Close()
+			return nil, err
+		}
+		if !walletInfo.Voting || !walletInfo.Unlocked {
+			c.Close()
+			return nil, fmt.Errorf("wallet %s has voting disabled", addr)
+		}
+
 		return c, nil
 	}
 }