compare server and agent version for compatibility

drone/agent/agent.go

@@ -101,7 +101,7 @@ func loop(c *cli.Context) error {
 		),
 		rpc.WithHeader(
 			"X-Drone-Version",
-			version.Version,
+			version.Version.String(),
 		),
 	)
 	if err != nil {

drone/main.go

@@ -17,7 +17,7 @@ func main() {
 
 	app := cli.NewApp()
 	app.Name = "drone"
-	app.Version = version.Version
+	app.Version = version.Version.String()
 	app.Usage = "command line utility"
 	app.Flags = []cli.Flag{
 		cli.StringFlag{

plugins/internal/http.go

@@ -3,7 +3,6 @@ package internal
 import (
 	"bytes"
 	"encoding/json"
-	"errors"
 	"io"
 	"io/ioutil"
 	"net/http"
@@ -47,8 +46,14 @@ func Send(method, path string, in, out interface{}) error {
 	// if an error is encountered, parse and return the
 	// error response.
 	if resp.StatusCode > http.StatusPartialContent {
-		out, _ := ioutil.ReadAll(resp.Body)
-		return errors.New(string(out))
+		out, err := ioutil.ReadAll(resp.Body)
+		if err != nil {
+			return err
+		}
+		return &Error{
+			code: resp.StatusCode,
+			text: string(out),
+		}
 	}
 
 	// if a json response is expected, parse and return
@@ -59,3 +64,19 @@ func Send(method, path string, in, out interface{}) error {
 
 	return nil
 }
+
+// Error represents a http error.
+type Error struct {
+	code int
+	text string
+}
+
+// Code returns the http error code.
+func (e *Error) Code() int {
+	return e.code
+}
+
+// Error returns the error message in string format.
+func (e *Error) Error() string {
+	return e.text
+}

plugins/sender/plugin.go

@@ -18,12 +18,11 @@ func NewRemote(endpoint string) model.SenderService {
 
 func (p *plugin) SenderAllowed(user *model.User, repo *model.Repo, build *model.Build) (bool, error) {
 	path := fmt.Sprintf("%s/sender/%s/%s/%s", p.endpoint, repo.Owner, repo.Name, build.Sender)
-	out := new(model.Sender)
-	err := internal.Send("POST", path, build, out)
+	err := internal.Send("POST", path, build, nil)
 	if err != nil {
 		return false, err
 	}
-	return out.Allow, nil
+	return true, err
 }
 
 func (p *plugin) SenderCreate(repo *model.Repo, sender *model.Sender) error {

router/middleware/header/header.go

@@ -52,6 +52,6 @@ func Secure(c *gin.Context) {
 // version information to the HTTP response. This is intended
 // for debugging and troubleshooting.
 func Version(c *gin.Context) {
-	c.Header("X-DRONE-VERSION", version.Version)
+	c.Header("X-DRONE-VERSION", version.Version.String())
 	c.Next()
 }

router/middleware/version.go

@@ -8,5 +8,5 @@ import (
 // Version is a middleware function that appends the Drone version information
 // to the HTTP response. This is intended for debugging and troubleshooting.
 func Version(c *gin.Context) {
-	c.Header("X-DRONE-VERSION", version.Version)
+	c.Header("X-DRONE-VERSION", version.Version.String())
 }

server/pages.go

@@ -28,6 +28,10 @@ func ShowIndex(c *gin.Context) {
 // ShowLogin is a legacy endpoint that now redirects to
 // initiliaze the oauth flow
 func ShowLogin(c *gin.Context) {
+	if err := c.Query("error"); err != "" {
+		c.HTML(500, "error.html", gin.H{"error": err})
+		return
+	}
 	c.Redirect(303, "/authorize")
 }
 

server/rpc.go

@@ -7,15 +7,18 @@ import (
 	"log"
 	"strconv"
 
+	"github.com/Sirupsen/logrus"
 	"github.com/cncd/logging"
 	"github.com/cncd/pipeline/pipeline/rpc"
 	"github.com/cncd/pubsub"
 	"github.com/cncd/queue"
+	"github.com/coreos/go-semver/semver"
 	"github.com/gin-gonic/gin"
 
 	"github.com/drone/drone/model"
 	"github.com/drone/drone/remote"
 	"github.com/drone/drone/store"
+	"github.com/drone/drone/version"
 )
 
 // This file is a complete disaster because I'm trying to wedge in some
@@ -86,6 +89,17 @@ func RPCHandler(c *gin.Context) {
 		c.String(401, "Unable to connect agent. Invalid authorization token")
 		return
 	}
+
+	agent := semver.New(
+		c.Request.Header.Get("X-Drone-Version"),
+	)
+	logrus.Debugf("agent connected: ip address %s: version %s", c.ClientIP(), agent)
+	if agent.LessThan(version.Version) {
+		logrus.Warnf("Version mismatch. Agent version %s < Server version %s", agent, version.Version)
+		c.String(409, "Version mismatch. Agent version %s < Server version %s", agent, version.Version)
+		return
+	}
+
 	peer := RPC{
 		remote: remote.FromContext(c),
 		store:  store.FromContext(c),

server/template/files/error.html

@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <meta charset="utf-8"/>
+  <meta content="width=device-width, initial-scale=1" name="viewport"/>
+  <meta content="ie=edge" http-equiv="x-ua-compatible"/>
+  <link href="https://fonts.googleapis.com/css?family=Roboto" rel="stylesheet"/>
+  <link href="https://fonts.googleapis.com/css?family=Roboto+Mono" rel="stylesheet"/>
+  <link href="https://fonts.googleapis.com/icon?family=Material+Icons" rel="stylesheet"/>
+  <link href="/static/favicon.ico" rel="icon" type="image/x-icon"/>
+  <link rel="stylesheet" href="/static/app.css" />
+  <title>error | drone</title>
+</head>
+<body>
+  {{ .error }}
+</body>
+</html>

version/version.go

@@ -1,19 +1,23 @@
 package version
 
-import "fmt"
+import "github.com/coreos/go-semver/semver"
 
 var (
 	// VersionMajor is for an API incompatible changes
-	VersionMajor = 0
+	VersionMajor int64 = 0
 	// VersionMinor is for functionality in a backwards-compatible manner
-	VersionMinor = 6
+	VersionMinor int64 = 6
 	// VersionPatch is for backwards-compatible bug fixes
-	VersionPatch = 0
+	VersionPatch int64 = 0
 
 	// VersionDev indicates development branch. Releases will be empty string.
-	VersionDev = "dev"
+	VersionDev string
 )
 
 // Version is the specification version that the package types support.
-var Version = fmt.Sprintf("%d.%d.%d+%s",
-	VersionMajor, VersionMinor, VersionPatch, VersionDev)
+var Version = semver.Version{
+	Major:    VersionMajor,
+	Minor:    VersionMinor,
+	Patch:    VersionPatch,
+	Metadata: VersionDev,
+}