Add vspd versioning

docs/api.md

@@ -43,7 +43,8 @@ when a VSP is closed will result in an error.
         "pubkey":"SjAmrAqH7LScCUwM1qo5O6Cu7aKhrM1ORszgZwD7HmU=",
         "feepercentage":3.0,
         "vspclosed":false,
-        "network":"testnet3"
+        "network":"testnet3",
+        "vspdversion":"1.0.0-pre"
     }
     ```
 

version/version.go

@@ -0,0 +1,61 @@
+package version
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+)
+
+// semverAlphabet is an alphabet of all characters allowed in semver prerelease
+// identifiers, and the . separator.
+const semverAlphabet = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-."
+
+// Constants defining the application version number.
+const (
+	Major = 1
+	Minor = 0
+	Patch = 0
+)
+
+// PreRelease contains the prerelease name of the application. It is a variable
+// so it can be modified at link time (e.g.
+// `-ldflags "-X decred.org/vspd/version.PreRelease=rc1"`).
+// It must only contain characters from the semantic version alphabet.
+var PreRelease = "pre"
+
+// String returns the application version as a properly formed string per the
+// semantic versioning 2.0.0 spec (https://semver.org/).
+func String() string {
+	// Start with the major, minor, and path versions.
+	version := fmt.Sprintf("%d.%d.%d", Major, Minor, Patch)
+
+	// Append pre-release version if there is one. The hyphen called for
+	// by the semantic versioning spec is automatically appended and should
+	// not be contained in the pre-release string. The pre-release version
+	// is not appended if it contains invalid characters.
+	preRelease := normalizeVerString(PreRelease)
+	if preRelease != "" {
+		version = version + "-" + preRelease
+	}
+
+	return version
+}
+
+// normalizeVerString returns the passed string stripped of all characters which
+// are not valid according to the semantic versioning guidelines for pre-release
+// version and build metadata strings. In particular they MUST only contain
+// characters in semanticAlphabet.
+func normalizeVerString(str string) string {
+	var buf bytes.Buffer
+	for _, r := range str {
+		if strings.ContainsRune(semverAlphabet, r) {
+			_, err := buf.WriteRune(r)
+			// Writing to a bytes.Buffer panics on OOM, and all
+			// errors are unexpected.
+			if err != nil {
+				panic(err)
+			}
+		}
+	}
+	return buf.String()
+}

vspd.go

@@ -5,11 +5,13 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"runtime"
 	"sync"
 
 	"github.com/decred/vspd/background"
 	"github.com/decred/vspd/database"
 	"github.com/decred/vspd/rpc"
+	"github.com/decred/vspd/version"
 	"github.com/decred/vspd/webapi"
 )
 
@@ -39,6 +41,10 @@ func run(ctx context.Context) error {
 		return err
 	}
 
+	// Show version at startup.
+	log.Infof("Version %s (Go version %s %s/%s)", version.String(), runtime.Version(),
+		runtime.GOOS, runtime.GOARCH)
+
 	if cfg.VspClosed {
 		log.Warnf("Config --vspclosed is set. This will prevent vspd from " +
 			"accepting new tickets.")

webapi/types.go

@@ -6,6 +6,7 @@ type vspInfoResponse struct {
 	FeePercentage float64 `json:"feepercentage"`
 	VspClosed     bool    `json:"vspclosed"`
 	Network       string  `json:"network"`
+	VspdVersion   string  `json:"vspdversion"`
 }
 
 type FeeAddressRequest struct {

webapi/vspstatus.go

@@ -3,6 +3,7 @@ package webapi
 import (
 	"time"
 
+	"github.com/decred/vspd/version"
 	"github.com/gin-gonic/gin"
 )
 
@@ -14,5 +15,6 @@ func vspInfo(c *gin.Context) {
 		FeePercentage: cfg.VSPFee,
 		Network:       cfg.NetParams.Name,
 		VspClosed:     cfg.VspClosed,
+		VspdVersion:   version.String(),
 	}, c)
 }