Merge pull request #1562 from SvenDowideit/make-upgrade-more-robust

Improve and test install and upgrade robustness

cmd/control/install.go

@@ -15,6 +15,7 @@ import (
 	"github.com/rancher/os/log"
 
 	"github.com/codegangsta/cli"
+	version "github.com/hashicorp/go-version"
 	"github.com/rancher/os/cmd/control/install"
 	"github.com/rancher/os/cmd/power"
 	"github.com/rancher/os/config"
@@ -165,11 +166,23 @@ func runInstall(image, installType, cloudConfig, device, kappend string, force,
 		diskType = "gpt"
 	}
 
-	// Versions before 0.8.0-rc2 use the old calling convention (from the lay-down-os shell script)
+	// Versions before 0.8.0-rc3 use the old calling convention (from the lay-down-os shell script)
-	// TODO: This needs fixing before 0.8.0 GA's - actually parse the version string, and use for any numbered version before 0.8.0-rc3
 	imageVersion := strings.TrimPrefix(image, "rancher/os:")
-	if imageVersion == "v0.7.1" || imageVersion == "v0.7.0" || imageVersion == "v0.5.0" {
+	installVer, err := version.NewVersion("999.999")
-		log.Infof("user specified to install 0.7.0/0.7.1: %s", image)
+	if strings.HasPrefix(imageVersion, "v") {
+		installVer, err = version.NewVersion(strings.TrimPrefix(imageVersion, "v"))
+		if err != nil {
+			log.Errorf("ERROR parsing %s: %s", imageVersion, err)
+			os.Exit(1)
+		}
+	}
+	newInstallerVersion, err := version.NewVersion("0.8.0-rc3")
+	if err != nil {
+		log.Errorf("ERROR parsing %s: %s", "0.8.0-rc3", err)
+		os.Exit(1)
+	}
+	if installVer.LessThan(newInstallerVersion) {
+		log.Infof("user specified to install pre v0.8.0: %s", image)
 		imageVersion = strings.Replace(imageVersion, "-", ".", -1)
 		vArray := strings.Split(imageVersion, ".")
 		v, _ := strconv.ParseFloat(vArray[0]+"."+vArray[1], 32)
@@ -207,7 +220,7 @@ func runInstall(image, installType, cloudConfig, device, kappend string, force,
 	if !isoinstallerloaded {
 		log.Infof("start !isoinstallerloaded")
 
-		if _, err := os.Stat("/dist/initrd"); os.IsNotExist(err) {
+		if _, err := os.Stat("/dist/initrd-" + config.Version); os.IsNotExist(err) {
 			if err = mountBootIso(); err != nil {
 				log.Debugf("mountBootIso error %s", err)
 			} else {
@@ -224,8 +237,11 @@ func runInstall(image, installType, cloudConfig, device, kappend string, force,
 						useIso = true
 						// now use the installer image
 						cfg := config.LoadConfig()
-						// TODO: fix the fullinstaller Dockerfile to use the ${VERSION}${SUFFIX}
+
-						image = cfg.Rancher.Upgrade.Image + "-installer" + ":latest"
+						if image == cfg.Rancher.Upgrade.Image+":"+config.Version+config.Suffix {
+							// TODO: fix the fullinstaller Dockerfile to use the ${VERSION}${SUFFIX}
+							image = cfg.Rancher.Upgrade.Image + "-installer" + ":latest"
+						}
 					}
 				}
 				// TODO: also poke around looking for the /boot/vmlinuz and initrd...
@@ -312,7 +328,7 @@ func runInstall(image, installType, cloudConfig, device, kappend string, force,
 		}
 	}
 
-	err := layDownOS(image, installType, cloudConfig, device, kappend, kexec)
+	err = layDownOS(image, installType, cloudConfig, device, kappend, kexec)
 	if err != nil {
 		log.Errorf("error layDownOS %s", err)
 		return err
@@ -833,37 +849,42 @@ func upgradeBootloader(device, baseName, bootDir, diskType string) error {
 	}
 
 	syslinuxDir := filepath.Join(baseName, bootDir+"syslinux")
-	backupSyslinuxDir := filepath.Join(baseName, bootDir+"syslinux_backup")
+	// it seems that v0.5.0 didn't have a syslinux dir, while 0.7 does
-	if err := os.Rename(syslinuxDir, backupSyslinuxDir); err != nil {
+	if _, err := os.Stat(syslinuxDir); !os.IsNotExist(err) {
-		log.Errorf("Rename(%s, %s): %s", syslinuxDir, backupSyslinuxDir, err)
+		backupSyslinuxDir := filepath.Join(baseName, bootDir+"syslinux_backup")
-		return err
+		if err := os.Rename(syslinuxDir, backupSyslinuxDir); err != nil {
-	}
+			log.Infof("error Rename(%s, %s): %s", syslinuxDir, backupSyslinuxDir, err)
-	//mv the old syslinux into linux-previous.cfg
+		} else {
-	oldSyslinux, err := ioutil.ReadFile(filepath.Join(backupSyslinuxDir, "syslinux.cfg"))
+			log.Errorf("Rename(%s, %s): ok", syslinuxDir, backupSyslinuxDir)
-	if err != nil {
+			//mv the old syslinux into linux-previous.cfg
-		log.Errorf("read(%s / syslinux.cfg): %s", backupSyslinuxDir, err)
+			oldSyslinux, err := ioutil.ReadFile(filepath.Join(backupSyslinuxDir, "syslinux.cfg"))
+			if err != nil {
+				log.Infof("error read(%s / syslinux.cfg): %s", backupSyslinuxDir, err)
+			} else {
+				log.Infof("read(%s / syslinux.cfg): ok", backupSyslinuxDir)
+				cfg := string(oldSyslinux)
+				//DEFAULT RancherOS-current
+				//
+				//LABEL RancherOS-current
+				//    LINUX ../vmlinuz-v0.7.1-rancheros
+				//    APPEND rancher.state.dev=LABEL=RANCHER_STATE rancher.state.wait console=tty0 rancher.password=rancher
+				//    INITRD ../initrd-v0.7.1-rancheros
 
-		return err
+				cfg = strings.Replace(cfg, "current", "previous", -1)
-	}
+				// TODO consider removing the APPEND line - as the global.cfg should have the same result
-	cfg := string(oldSyslinux)
+				ioutil.WriteFile(filepath.Join(baseName, bootDir, "linux-current.cfg"), []byte(cfg), 0644)
-	//DEFAULT RancherOS-current
-	//
-	//LABEL RancherOS-current
-	//    LINUX ../vmlinuz-v0.7.1-rancheros
-	//    APPEND rancher.state.dev=LABEL=RANCHER_STATE rancher.state.wait console=tty0 rancher.password=rancher
-	//    INITRD ../initrd-v0.7.1-rancheros
 
-	cfg = strings.Replace(cfg, "current", "previous", -1)
+				lines := strings.Split(cfg, "\n")
-	// TODO consider removing the APPEND line - as the global.cfg should have the same result
+				for _, line := range lines {
-	ioutil.WriteFile(filepath.Join(baseName, bootDir, "linux-current.cfg"), []byte(cfg), 0644)
+					line = strings.TrimSpace(line)
-
+					if strings.HasPrefix(line, "APPEND") {
-	lines := strings.Split(cfg, "\n")
+						// TODO: need to append any extra's the user specified
-	for _, line := range lines {
+						log.Infof("wrote (%s) to global.cfg", []byte(cfg))
-		line = strings.TrimSpace(line)
+						ioutil.WriteFile(filepath.Join(baseName, bootDir, "global.cfg"), []byte(cfg), 0644)
-		if strings.HasPrefix(line, "APPEND") {
+						break
-			// TODO: need to append any extra's the user specified
+					}
-			ioutil.WriteFile(filepath.Join(baseName, bootDir, "global.cfg"), []byte(cfg), 0644)
+				}
-			break
+			}
 		}
 	}
 
@@ -918,8 +939,11 @@ func installSyslinux(device, baseName, bootDir, diskType string) error {
 			return err
 		}
 	}
-	if err := os.MkdirAll(filepath.Join(baseName, bootDir+"syslinux"), 0755); err != nil {
+
-		return err
+	sysLinuxDir := filepath.Join(baseName, bootDir, "syslinux")
+	if err := os.MkdirAll(sysLinuxDir, 0755); err != nil {
+		log.Errorf("MkdirAll(%s)): %s", sysLinuxDir, err)
+		//return err
 	}
 
 	//cp /usr/lib/syslinux/modules/bios/* ${baseName}/${bootDir}syslinux
@@ -928,17 +952,17 @@ func installSyslinux(device, baseName, bootDir, diskType string) error {
 		if file.IsDir() {
 			continue
 		}
-		if err := dfs.CopyFile(filepath.Join("/usr/share/syslinux/", file.Name()), filepath.Join(baseName, bootDir, "syslinux"), file.Name()); err != nil {
+		if err := dfs.CopyFile(filepath.Join("/usr/share/syslinux/", file.Name()), sysLinuxDir, file.Name()); err != nil {
 			log.Errorf("copy syslinux: %s", err)
 			return err
 		}
 	}
 
 	//extlinux --install ${baseName}/${bootDir}syslinux
-	cmd := exec.Command("extlinux", "--install", filepath.Join(baseName, bootDir+"syslinux"))
+	cmd := exec.Command("extlinux", "--install", sysLinuxDir)
 	if device == "/dev/" {
 		//extlinux --install --raid ${baseName}/${bootDir}syslinux
-		cmd = exec.Command("extlinux", "--install", "--raid", filepath.Join(baseName, bootDir+"syslinux"))
+		cmd = exec.Command("extlinux", "--install", "--raid", sysLinuxDir)
 	}
 	//cmd.Stdout, cmd.Stderr = os.Stdout, os.Stderr
 	log.Debugf("Run(%v)", cmd)
@@ -972,21 +996,24 @@ func installRancher(baseName, bootDir, VERSION, DIST, kappend string) error {
 		}
 		if err := dfs.CopyFile(filepath.Join(DIST, file.Name()), filepath.Join(baseName, bootDir), file.Name()); err != nil {
 			log.Errorf("copy %s: %s", file.Name(), err)
-			return err
+			//return err
 		}
 		log.Debugf("copied %s to %s as %s", filepath.Join(DIST, file.Name()), filepath.Join(baseName, bootDir), file.Name())
 	}
 	// the general INCLUDE syslinuxcfg
 	if err := dfs.CopyFile(filepath.Join(DIST, "isolinux", "isolinux.cfg"), filepath.Join(baseName, bootDir, "syslinux"), "syslinux.cfg"); err != nil {
-		log.Errorf("copy %s: %s", "syslinux.cfg", err)
+		log.Errorf("copy global syslinux.cfgS%s: %s", "syslinux.cfg", err)
-		return err
+		//return err
 	}
 
 	// The global.cfg INCLUDE - useful for over-riding the APPEND line
-	err := ioutil.WriteFile(filepath.Join(filepath.Join(baseName, bootDir), "global.cfg"), []byte("APPEND "+kappend), 0644)
+	globalFile := filepath.Join(filepath.Join(baseName, bootDir), "global.cfg")
-	if err != nil {
+	if _, err := os.Stat(globalFile); !os.IsNotExist(err) {
-		log.Errorf("write (%s) %s", "global.cfg", err)
+		err := ioutil.WriteFile(globalFile, []byte("APPEND "+kappend), 0644)
-		return err
+		if err != nil {
+			log.Errorf("write (%s) %s", "global.cfg", err)
+			return err
+		}
 	}
 	return nil
 }

tests/common_test.go

@@ -184,3 +184,15 @@ func (s *QemuSuite) LoadInstallerImage(c *C) {
 	cmd.Stderr = os.Stderr
 	c.Assert(cmd.Run(), IsNil)
 }
+
+func (s *QemuSuite) PullAndLoadInstallerImage(c *C, image string) {
+	cmd := exec.Command("sh", "-c", fmt.Sprintf("docker pull %s", image))
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	c.Assert(cmd.Run(), IsNil)
+
+	cmd = exec.Command("sh", "-c", fmt.Sprintf("docker save %s | ../scripts/ssh --qemu sudo system-docker load", image))
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	c.Assert(cmd.Run(), IsNil)
+}

tests/installer_test.go

@@ -80,73 +80,3 @@ sync
 	// TEST parted output? (gpt non-uefi == legacy_boot)
 	s.Stop(c)
 }
-
-func (s *QemuSuite) TestUpgradeFromImage(c *C) {
-	// ./scripts/run --no-format --append "rancher.debug=true"  --iso --fresh
-
-	//TODO: --fresh isn't giving us a new disk why? (that's what the parted print is for atm)
-	runArgs := []string{
-		"--iso",
-		"--fresh",
-	}
-	version := ""
-	{
-		s.RunQemuWith(c, runArgs...)
-
-		version = s.CheckOutput(c, version, Not(Equals), "sudo ros -v")
-		fmt.Printf("running %s", version)
-		s.CheckCall(c, "sudo uname -a")
-		//TODO: detect "last release, and install that
-		s.CheckCall(c, `
-echo "---------------------------------- generic"
-set -ex
-sudo parted /dev/vda print
-echo "ssh_authorized_keys:" > config.yml
-echo "  - $(cat /home/rancher/.ssh/authorized_keys)" >> config.yml
-sudo ros install --force --no-reboot --device /dev/vda -c config.yml -i rancher/os:v0.7.1 --append "console=ttyS0 rancher.password=rancher"
-#TODO copy installer image, new ros, and new kernel to HD, so we can fake things up next time? (or have next boot from HD, but have the iso available..)
-sudo mkdir -p /bootiso
-sudo mount -t iso9660 /dev/sr0 /bootiso/
-sudo mount /dev/vda1 /mnt/
-sudo mkdir -p /mnt/rancher-installer/build/ 
-sudo cp /bootiso/rancheros/installer.tar.gz /mnt/rancher-installer/build/
-sudo cp /bootiso/rancheros/Dockerfile.amd64 /mnt/rancher-installer/build/
-sudo cp -r /bootiso/boot /mnt/rancher-installer/build/
-sudo cp /bin/ros /mnt/rancher-installer/build/
-sync
-`)
-		time.Sleep(500 * time.Millisecond)
-		s.Stop(c)
-	}
-
-	{
-		runArgs = []string{
-			"--boothd",
-		}
-		s.RunQemuWith(c, runArgs...)
-
-		s.CheckOutput(c, "ros version v0.7.1\n", Equals, "sudo ros -v")
-		s.CheckCall(c, "sudo uname -a")
-
-		// load the installer.tar.gz, get the other install files into an image, and runit.
-		s.CheckCall(c, `sudo system-docker run --name builder -dt --volumes-from system-volumes -v /:/host alpine sh
-	sudo system-docker exec -t builder ln -s /host/rancher-installer/build/ros /bin/system-docker
-	sudo system-docker exec -t builder system-docker load -i /host/rancher-installer/build/installer.tar.gz
-	sudo system-docker exec -t builder system-docker build -t qwer -f /host/rancher-installer/build/Dockerfile.amd64 /host/rancher-installer/build
-	sudo ros os upgrade -i qwer --no-reboot -f --append "console=tty0 console=ttyS0 rancher.password=rancher"
-	sync
-	`)
-		time.Sleep(500 * time.Millisecond)
-		s.Stop(c)
-	}
-
-	// ./scripts/run --no-format --append "rancher.debug=true"
-	runArgs = []string{
-		"--boothd",
-	}
-	s.RunQemuWith(c, runArgs...)
-
-	s.CheckOutput(c, version, Equals, "sudo ros -v")
-	s.CheckCall(c, "sudo uname -a")
-	s.Stop(c)
-}

tests/upgrade_test.go

@@ -2,28 +2,82 @@ package integration
 
 import (
 	"fmt"
+	"time"
+
+	"strings"
 
 	. "gopkg.in/check.v1"
 )
 
-// DisabledTestUpgrade, The new go based installer code breaks downgrading from itself to a previous version
+func (s *QemuSuite) TestUpgrade050(c *C) {
-// because 0.8.0 now uses syslinx and a set of syslinux.cfg files, whereas before that , we used grub and
+	s.commonTestCode(c, "v0.5.0", "debian")
-// assumed that there was only one kernel&initrd
+}
-//      see installer_test.go for more tests
+func (s *QemuSuite) TestUpgrade070(c *C) {
-func (s *QemuSuite) DisabledTestUpgrade(c *C) {
+	s.commonTestCode(c, "v0.7.0", "default")
-	s.RunQemuInstalled(c)
+}
-
+func (s *QemuSuite) TestUpgrade071(c *C) {
-	s.CheckCall(c, `
+	s.commonTestCode(c, "v0.7.1", "ubuntu")
-set -ex
+}
-sudo ros os upgrade -i rancher/os:v0.5.0 --force --no-reboot`)
+func (s *QemuSuite) TestUpgrade080rc1(c *C) {
-
+	s.commonTestCode(c, "v0.8.0-rc1", "alpine")
-	s.Reboot(c)
+}
-
+func (s *QemuSuite) TestUpgrade080rc7(c *C) {
-	s.CheckCall(c, "sudo ros -v | grep v0.5.0")
+	s.commonTestCode(c, "v0.8.0-rc7", "centos")
-	s.LoadInstallerImage(c)
+}
-	s.CheckCall(c, fmt.Sprintf("sudo ros os upgrade -i rancher/os:%s%s --force --no-reboot", Version, Suffix))
+
-
+func (s *QemuSuite) commonTestCode(c *C, startWithVersion, console string) {
-	s.Reboot(c)
+	runArgs := []string{
-
+		"--iso",
-	s.CheckCall(c, fmt.Sprintf("sudo ros -v | grep %s", Version))
+		"--fresh",
+		"--cloud-config",
+		"./tests/assets/test_12/cloud-config.yml",
+	}
+	version := ""
+	{
+		s.RunQemuWith(c, runArgs...)
+		version = s.CheckOutput(c, version, Not(Equals), "sudo ros -v")
+		version = strings.TrimSpace(strings.TrimPrefix(version, "ros version"))
+		c.Assert(Version, Equals, version)
+
+		fmt.Printf("installing %s", startWithVersion)
+		s.PullAndLoadInstallerImage(c, fmt.Sprintf("rancher/os:%s", startWithVersion))
+
+		//ADD a custom append line and make sure its kept in the upgraded version too
+
+		s.CheckCall(c, fmt.Sprintf(`
+echo "---------------------------------- generic"
+set -ex
+echo "ssh_authorized_keys:" > config.yml
+echo "  - $(cat /home/rancher/.ssh/authorized_keys)" >> config.yml
+sudo ros install --force --no-reboot --device /dev/vda -c config.yml --append rancher.password=rancher -i rancher/os:%s
+sync
+		`, startWithVersion))
+		time.Sleep(500 * time.Millisecond)
+		s.Stop(c)
+	}
+
+	// ./scripts/run --no-format --append "rancher.debug=true"
+	runArgs = []string{
+		"--boothd",
+	}
+	s.RunQemuWith(c, runArgs...)
+
+	s.CheckOutput(c, "ros version "+startWithVersion+"\n", Equals, "sudo ros -v")
+
+	if console != "default" {
+		// Can't preload the startWithVersion console image, as some don't exist by that name - not sure how to approach that
+		//s.PullAndLoadInstallerImage(c, fmt.Sprintf("rancher/os-%sconsole:%s", console, startWithVersion))
+		// TODO: ouch. probably need to tag the dev / master version as latest cos this won't work
+		// Need to pull the image here - if we do it at boot, then the test will fail.
+		s.PullAndLoadInstallerImage(c, fmt.Sprintf("rancher/os-%sconsole:%s", console, "v0.8.0-rc3"))
+		s.CheckCall(c, fmt.Sprintf("sudo ros console enable %s", console))
+	}
+
+	s.LoadInstallerImage(c)
+	s.CheckCall(c, fmt.Sprintf("sudo ros os upgrade --no-reboot -i rancher/os:%s%s --force", Version, Suffix))
+
+	s.Reboot(c)
+	s.CheckOutput(c, "ros version "+Version+"\n", Equals, "sudo ros -v")
+
+	s.Stop(c)
 }

trash.conf

@@ -26,6 +26,7 @@ github.com/godbus/dbus v3
 github.com/golang/protobuf 8d92cf5fc15a4382f8964b08e1f42a75c0591aa3
 github.com/gorilla/context 14f550f51a 
 github.com/gorilla/mux e444e69cbd 
+github.com/hashicorp/go-version e96d3840402619007766590ecea8dd7af1292276
 github.com/imdario/mergo 0.2.1
 github.com/j-keck/arping 4f4d2c8983a18e2c9c63a3f339bc9a998c4557bc
 github.com/kless/term d57d9d2d5be197e12d9dee142d855470d83ce62f

vendor/github.com/hashicorp/go-version/.travis.yml

@@ -0,0 +1,11 @@
+language: go 
+
+go: 
+  - 1.0
+  - 1.1 
+  - 1.2
+  - 1.3
+  - 1.4
+  
+script:
+  - go test 

vendor/github.com/hashicorp/go-version/LICENSE

@@ -0,0 +1,354 @@
+Mozilla Public License, version 2.0
+
+1. Definitions
+
+1.1. “Contributor”
+
+     means each individual or legal entity that creates, contributes to the
+     creation of, or owns Covered Software.
+
+1.2. “Contributor Version”
+
+     means the combination of the Contributions of others (if any) used by a
+     Contributor and that particular Contributor’s Contribution.
+
+1.3. “Contribution”
+
+     means Covered Software of a particular Contributor.
+
+1.4. “Covered Software”
+
+     means Source Code Form to which the initial Contributor has attached the
+     notice in Exhibit A, the Executable Form of such Source Code Form, and
+     Modifications of such Source Code Form, in each case including portions
+     thereof.
+
+1.5. “Incompatible With Secondary Licenses”
+     means
+
+     a. that the initial Contributor has attached the notice described in
+        Exhibit B to the Covered Software; or
+
+     b. that the Covered Software was made available under the terms of version
+        1.1 or earlier of the License, but not also under the terms of a
+        Secondary License.
+
+1.6. “Executable Form”
+
+     means any form of the work other than Source Code Form.
+
+1.7. “Larger Work”
+
+     means a work that combines Covered Software with other material, in a separate
+     file or files, that is not Covered Software.
+
+1.8. “License”
+
+     means this document.
+
+1.9. “Licensable”
+
+     means having the right to grant, to the maximum extent possible, whether at the
+     time of the initial grant or subsequently, any and all of the rights conveyed by
+     this License.
+
+1.10. “Modifications”
+
+     means any of the following:
+
+     a. any file in Source Code Form that results from an addition to, deletion
+        from, or modification of the contents of Covered Software; or
+
+     b. any new file in Source Code Form that contains any Covered Software.
+
+1.11. “Patent Claims” of a Contributor
+
+      means any patent claim(s), including without limitation, method, process,
+      and apparatus claims, in any patent Licensable by such Contributor that
+      would be infringed, but for the grant of the License, by the making,
+      using, selling, offering for sale, having made, import, or transfer of
+      either its Contributions or its Contributor Version.
+
+1.12. “Secondary License”
+
+      means either the GNU General Public License, Version 2.0, the GNU Lesser
+      General Public License, Version 2.1, the GNU Affero General Public
+      License, Version 3.0, or any later versions of those licenses.
+
+1.13. “Source Code Form”
+
+      means the form of the work preferred for making modifications.
+
+1.14. “You” (or “Your”)
+
+      means an individual or a legal entity exercising rights under this
+      License. For legal entities, “You” includes any entity that controls, is
+      controlled by, or is under common control with You. For purposes of this
+      definition, “control” means (a) the power, direct or indirect, to cause
+      the direction or management of such entity, whether by contract or
+      otherwise, or (b) ownership of more than fifty percent (50%) of the
+      outstanding shares or beneficial ownership of such entity.
+
+
+2. License Grants and Conditions
+
+2.1. Grants
+
+     Each Contributor hereby grants You a world-wide, royalty-free,
+     non-exclusive license:
+
+     a. under intellectual property rights (other than patent or trademark)
+        Licensable by such Contributor to use, reproduce, make available,
+        modify, display, perform, distribute, and otherwise exploit its
+        Contributions, either on an unmodified basis, with Modifications, or as
+        part of a Larger Work; and
+
+     b. under Patent Claims of such Contributor to make, use, sell, offer for
+        sale, have made, import, and otherwise transfer either its Contributions
+        or its Contributor Version.
+
+2.2. Effective Date
+
+     The licenses granted in Section 2.1 with respect to any Contribution become
+     effective for each Contribution on the date the Contributor first distributes
+     such Contribution.
+
+2.3. Limitations on Grant Scope
+
+     The licenses granted in this Section 2 are the only rights granted under this
+     License. No additional rights or licenses will be implied from the distribution
+     or licensing of Covered Software under this License. Notwithstanding Section
+     2.1(b) above, no patent license is granted by a Contributor:
+
+     a. for any code that a Contributor has removed from Covered Software; or
+
+     b. for infringements caused by: (i) Your and any other third party’s
+        modifications of Covered Software, or (ii) the combination of its
+        Contributions with other software (except as part of its Contributor
+        Version); or
+
+     c. under Patent Claims infringed by Covered Software in the absence of its
+        Contributions.
+
+     This License does not grant any rights in the trademarks, service marks, or
+     logos of any Contributor (except as may be necessary to comply with the
+     notice requirements in Section 3.4).
+
+2.4. Subsequent Licenses
+
+     No Contributor makes additional grants as a result of Your choice to
+     distribute the Covered Software under a subsequent version of this License
+     (see Section 10.2) or under the terms of a Secondary License (if permitted
+     under the terms of Section 3.3).
+
+2.5. Representation
+
+     Each Contributor represents that the Contributor believes its Contributions
+     are its original creation(s) or it has sufficient rights to grant the
+     rights to its Contributions conveyed by this License.
+
+2.6. Fair Use
+
+     This License is not intended to limit any rights You have under applicable
+     copyright doctrines of fair use, fair dealing, or other equivalents.
+
+2.7. Conditions
+
+     Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted in
+     Section 2.1.
+
+
+3. Responsibilities
+
+3.1. Distribution of Source Form
+
+     All distribution of Covered Software in Source Code Form, including any
+     Modifications that You create or to which You contribute, must be under the
+     terms of this License. You must inform recipients that the Source Code Form
+     of the Covered Software is governed by the terms of this License, and how
+     they can obtain a copy of this License. You may not attempt to alter or
+     restrict the recipients’ rights in the Source Code Form.
+
+3.2. Distribution of Executable Form
+
+     If You distribute Covered Software in Executable Form then:
+
+     a. such Covered Software must also be made available in Source Code Form,
+        as described in Section 3.1, and You must inform recipients of the
+        Executable Form how they can obtain a copy of such Source Code Form by
+        reasonable means in a timely manner, at a charge no more than the cost
+        of distribution to the recipient; and
+
+     b. You may distribute such Executable Form under the terms of this License,
+        or sublicense it under different terms, provided that the license for
+        the Executable Form does not attempt to limit or alter the recipients’
+        rights in the Source Code Form under this License.
+
+3.3. Distribution of a Larger Work
+
+     You may create and distribute a Larger Work under terms of Your choice,
+     provided that You also comply with the requirements of this License for the
+     Covered Software. If the Larger Work is a combination of Covered Software
+     with a work governed by one or more Secondary Licenses, and the Covered
+     Software is not Incompatible With Secondary Licenses, this License permits
+     You to additionally distribute such Covered Software under the terms of
+     such Secondary License(s), so that the recipient of the Larger Work may, at
+     their option, further distribute the Covered Software under the terms of
+     either this License or such Secondary License(s).
+
+3.4. Notices
+
+     You may not remove or alter the substance of any license notices (including
+     copyright notices, patent notices, disclaimers of warranty, or limitations
+     of liability) contained within the Source Code Form of the Covered
+     Software, except that You may alter any license notices to the extent
+     required to remedy known factual inaccuracies.
+
+3.5. Application of Additional Terms
+
+     You may choose to offer, and to charge a fee for, warranty, support,
+     indemnity or liability obligations to one or more recipients of Covered
+     Software. However, You may do so only on Your own behalf, and not on behalf
+     of any Contributor. You must make it absolutely clear that any such
+     warranty, support, indemnity, or liability obligation is offered by You
+     alone, and You hereby agree to indemnify every Contributor for any
+     liability incurred by such Contributor as a result of warranty, support,
+     indemnity or liability terms You offer. You may include additional
+     disclaimers of warranty and limitations of liability specific to any
+     jurisdiction.
+
+4. Inability to Comply Due to Statute or Regulation
+
+   If it is impossible for You to comply with any of the terms of this License
+   with respect to some or all of the Covered Software due to statute, judicial
+   order, or regulation then You must: (a) comply with the terms of this License
+   to the maximum extent possible; and (b) describe the limitations and the code
+   they affect. Such description must be placed in a text file included with all
+   distributions of the Covered Software under this License. Except to the
+   extent prohibited by statute or regulation, such description must be
+   sufficiently detailed for a recipient of ordinary skill to be able to
+   understand it.
+
+5. Termination
+
+5.1. The rights granted under this License will terminate automatically if You
+     fail to comply with any of its terms. However, if You become compliant,
+     then the rights granted under this License from a particular Contributor
+     are reinstated (a) provisionally, unless and until such Contributor
+     explicitly and finally terminates Your grants, and (b) on an ongoing basis,
+     if such Contributor fails to notify You of the non-compliance by some
+     reasonable means prior to 60 days after You have come back into compliance.
+     Moreover, Your grants from a particular Contributor are reinstated on an
+     ongoing basis if such Contributor notifies You of the non-compliance by
+     some reasonable means, this is the first time You have received notice of
+     non-compliance with this License from such Contributor, and You become
+     compliant prior to 30 days after Your receipt of the notice.
+
+5.2. If You initiate litigation against any entity by asserting a patent
+     infringement claim (excluding declaratory judgment actions, counter-claims,
+     and cross-claims) alleging that a Contributor Version directly or
+     indirectly infringes any patent, then the rights granted to You by any and
+     all Contributors for the Covered Software under Section 2.1 of this License
+     shall terminate.
+
+5.3. In the event of termination under Sections 5.1 or 5.2 above, all end user
+     license agreements (excluding distributors and resellers) which have been
+     validly granted by You or Your distributors under this License prior to
+     termination shall survive termination.
+
+6. Disclaimer of Warranty
+
+   Covered Software is provided under this License on an “as is” basis, without
+   warranty of any kind, either expressed, implied, or statutory, including,
+   without limitation, warranties that the Covered Software is free of defects,
+   merchantable, fit for a particular purpose or non-infringing. The entire
+   risk as to the quality and performance of the Covered Software is with You.
+   Should any Covered Software prove defective in any respect, You (not any
+   Contributor) assume the cost of any necessary servicing, repair, or
+   correction. This disclaimer of warranty constitutes an essential part of this
+   License. No use of  any Covered Software is authorized under this License
+   except under this disclaimer.
+
+7. Limitation of Liability
+
+   Under no circumstances and under no legal theory, whether tort (including
+   negligence), contract, or otherwise, shall any Contributor, or anyone who
+   distributes Covered Software as permitted above, be liable to You for any
+   direct, indirect, special, incidental, or consequential damages of any
+   character including, without limitation, damages for lost profits, loss of
+   goodwill, work stoppage, computer failure or malfunction, or any and all
+   other commercial damages or losses, even if such party shall have been
+   informed of the possibility of such damages. This limitation of liability
+   shall not apply to liability for death or personal injury resulting from such
+   party’s negligence to the extent applicable law prohibits such limitation.
+   Some jurisdictions do not allow the exclusion or limitation of incidental or
+   consequential damages, so this exclusion and limitation may not apply to You.
+
+8. Litigation
+
+   Any litigation relating to this License may be brought only in the courts of
+   a jurisdiction where the defendant maintains its principal place of business
+   and such litigation shall be governed by laws of that jurisdiction, without
+   reference to its conflict-of-law provisions. Nothing in this Section shall
+   prevent a party’s ability to bring cross-claims or counter-claims.
+
+9. Miscellaneous
+
+   This License represents the complete agreement concerning the subject matter
+   hereof. If any provision of this License is held to be unenforceable, such
+   provision shall be reformed only to the extent necessary to make it
+   enforceable. Any law or regulation which provides that the language of a
+   contract shall be construed against the drafter shall not be used to construe
+   this License against a Contributor.
+
+
+10. Versions of the License
+
+10.1. New Versions
+
+      Mozilla Foundation is the license steward. Except as provided in Section
+      10.3, no one other than the license steward has the right to modify or
+      publish new versions of this License. Each version will be given a
+      distinguishing version number.
+
+10.2. Effect of New Versions
+
+      You may distribute the Covered Software under the terms of the version of
+      the License under which You originally received the Covered Software, or
+      under the terms of any subsequent version published by the license
+      steward.
+
+10.3. Modified Versions
+
+      If you create software not governed by this License, and you want to
+      create a new license for such software, you may create and use a modified
+      version of this License if you rename the license and remove any
+      references to the name of the license steward (except to note that such
+      modified license differs from this License).
+
+10.4. Distributing Source Code Form that is Incompatible With Secondary Licenses
+      If You choose to distribute Source Code Form that is Incompatible With
+      Secondary Licenses under the terms of this version of the License, the
+      notice described in Exhibit B of this License must be attached.
+
+Exhibit A - Source Code Form License Notice
+
+      This Source Code Form is subject to the
+      terms of the Mozilla Public License, v.
+      2.0. If a copy of the MPL was not
+      distributed with this file, You can
+      obtain one at
+      http://mozilla.org/MPL/2.0/.
+
+If it is not possible or desirable to put the notice in a particular file, then
+You may include the notice in a location (such as a LICENSE file in a relevant
+directory) where a recipient would be likely to look for such a notice.
+
+You may add additional accurate notices of copyright ownership.
+
+Exhibit B - “Incompatible With Secondary Licenses” Notice
+
+      This Source Code Form is “Incompatible
+      With Secondary Licenses”, as defined by
+      the Mozilla Public License, v. 2.0.
+

vendor/github.com/hashicorp/go-version/README.md

@@ -0,0 +1,65 @@
+# Versioning Library for Go
+[![Build Status](https://travis-ci.org/hashicorp/go-version.svg?branch=master)](https://travis-ci.org/hashicorp/go-version)
+
+go-version is a library for parsing versions and version constraints,
+and verifying versions against a set of constraints. go-version
+can sort a collection of versions properly, handles prerelease/beta
+versions, can increment versions, etc.
+
+Versions used with go-version must follow [SemVer](http://semver.org/).
+
+## Installation and Usage
+
+Package documentation can be found on
+[GoDoc](http://godoc.org/github.com/hashicorp/go-version).
+
+Installation can be done with a normal `go get`:
+
+```
+$ go get github.com/hashicorp/go-version
+```
+
+#### Version Parsing and Comparison
+
+```go
+v1, err := version.NewVersion("1.2")
+v2, err := version.NewVersion("1.5+metadata")
+
+// Comparison example. There is also GreaterThan, Equal, and just
+// a simple Compare that returns an int allowing easy >=, <=, etc.
+if v1.LessThan(v2) {
+    fmt.Printf("%s is less than %s", v1, v2)
+}
+```
+
+#### Version Constraints
+
+```go
+v1, err := version.NewVersion("1.2")
+
+// Constraints example.
+constraints, err := version.NewConstraint(">= 1.0, < 1.4")
+if constraints.Check(v1) {
+	fmt.Printf("%s satisfies constraints %s", v1, constraints)
+}
+```
+
+#### Version Sorting
+
+```go
+versionsRaw := []string{"1.1", "0.7.1", "1.4-beta", "1.4", "2"}
+versions := make([]*version.Version, len(versionsRaw))
+for i, raw := range versionsRaw {
+    v, _ := version.NewVersion(raw)
+    versions[i] = v
+}
+
+// After this, the versions are properly sorted
+sort.Sort(version.Collection(versions))
+```
+
+## Issues and Contributing
+
+If you find an issue with this library, please report an issue. If you'd
+like, we welcome any contributions. Fork this library and submit a pull
+request.

vendor/github.com/hashicorp/go-version/constraint.go

@@ -0,0 +1,178 @@
+package version
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+// Constraint represents a single constraint for a version, such as
+// ">= 1.0".
+type Constraint struct {
+	f        constraintFunc
+	check    *Version
+	original string
+}
+
+// Constraints is a slice of constraints. We make a custom type so that
+// we can add methods to it.
+type Constraints []*Constraint
+
+type constraintFunc func(v, c *Version) bool
+
+var constraintOperators map[string]constraintFunc
+
+var constraintRegexp *regexp.Regexp
+
+func init() {
+	constraintOperators = map[string]constraintFunc{
+		"":   constraintEqual,
+		"=":  constraintEqual,
+		"!=": constraintNotEqual,
+		">":  constraintGreaterThan,
+		"<":  constraintLessThan,
+		">=": constraintGreaterThanEqual,
+		"<=": constraintLessThanEqual,
+		"~>": constraintPessimistic,
+	}
+
+	ops := make([]string, 0, len(constraintOperators))
+	for k := range constraintOperators {
+		ops = append(ops, regexp.QuoteMeta(k))
+	}
+
+	constraintRegexp = regexp.MustCompile(fmt.Sprintf(
+		`^\s*(%s)\s*(%s)\s*$`,
+		strings.Join(ops, "|"),
+		VersionRegexpRaw))
+}
+
+// NewConstraint will parse one or more constraints from the given
+// constraint string. The string must be a comma-separated list of
+// constraints.
+func NewConstraint(v string) (Constraints, error) {
+	vs := strings.Split(v, ",")
+	result := make([]*Constraint, len(vs))
+	for i, single := range vs {
+		c, err := parseSingle(single)
+		if err != nil {
+			return nil, err
+		}
+
+		result[i] = c
+	}
+
+	return Constraints(result), nil
+}
+
+// Check tests if a version satisfies all the constraints.
+func (cs Constraints) Check(v *Version) bool {
+	for _, c := range cs {
+		if !c.Check(v) {
+			return false
+		}
+	}
+
+	return true
+}
+
+// Returns the string format of the constraints
+func (cs Constraints) String() string {
+	csStr := make([]string, len(cs))
+	for i, c := range cs {
+		csStr[i] = c.String()
+	}
+
+	return strings.Join(csStr, ",")
+}
+
+// Check tests if a constraint is validated by the given version.
+func (c *Constraint) Check(v *Version) bool {
+	return c.f(v, c.check)
+}
+
+func (c *Constraint) String() string {
+	return c.original
+}
+
+func parseSingle(v string) (*Constraint, error) {
+	matches := constraintRegexp.FindStringSubmatch(v)
+	if matches == nil {
+		return nil, fmt.Errorf("Malformed constraint: %s", v)
+	}
+
+	check, err := NewVersion(matches[2])
+	if err != nil {
+		return nil, err
+	}
+
+	return &Constraint{
+		f:        constraintOperators[matches[1]],
+		check:    check,
+		original: v,
+	}, nil
+}
+
+//-------------------------------------------------------------------
+// Constraint functions
+//-------------------------------------------------------------------
+
+func constraintEqual(v, c *Version) bool {
+	return v.Equal(c)
+}
+
+func constraintNotEqual(v, c *Version) bool {
+	return !v.Equal(c)
+}
+
+func constraintGreaterThan(v, c *Version) bool {
+	return v.Compare(c) == 1
+}
+
+func constraintLessThan(v, c *Version) bool {
+	return v.Compare(c) == -1
+}
+
+func constraintGreaterThanEqual(v, c *Version) bool {
+	return v.Compare(c) >= 0
+}
+
+func constraintLessThanEqual(v, c *Version) bool {
+	return v.Compare(c) <= 0
+}
+
+func constraintPessimistic(v, c *Version) bool {
+	// If the version being checked is naturally less than the constraint, then there
+	// is no way for the version to be valid against the constraint
+	if v.LessThan(c) {
+		return false
+	}
+	// We'll use this more than once, so grab the length now so it's a little cleaner
+	// to write the later checks
+	cs := len(c.segments)
+
+	// If the version being checked has less specificity than the constraint, then there
+	// is no way for the version to be valid against the constraint
+	if cs > len(v.segments) {
+		return false
+	}
+
+	// Check the segments in the constraint against those in the version. If the version
+	// being checked, at any point, does not have the same values in each index of the
+	// constraints segments, then it cannot be valid against the constraint.
+	for i := 0; i < c.si-1; i++ {
+		if v.segments[i] != c.segments[i] {
+			return false
+		}
+	}
+
+	// Check the last part of the segment in the constraint. If the version segment at
+	// this index is less than the constraints segment at this index, then it cannot
+	// be valid against the constraint
+	if c.segments[cs-1] > v.segments[cs-1] {
+		return false
+	}
+
+	// If nothing has rejected the version by now, it's valid
+	return true
+}

vendor/github.com/hashicorp/go-version/version.go

@@ -0,0 +1,308 @@
+package version
+
+import (
+	"bytes"
+	"fmt"
+	"reflect"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+// The compiled regular expression used to test the validity of a version.
+var versionRegexp *regexp.Regexp
+
+// The raw regular expression string used for testing the validity
+// of a version.
+const VersionRegexpRaw string = `v?([0-9]+(\.[0-9]+)*?)` +
+	`(-?([0-9A-Za-z\-]+(\.[0-9A-Za-z\-]+)*))?` +
+	`(\+([0-9A-Za-z\-]+(\.[0-9A-Za-z\-]+)*))?` +
+	`?`
+
+// Version represents a single version.
+type Version struct {
+	metadata string
+	pre      string
+	segments []int64
+	si       int
+}
+
+func init() {
+	versionRegexp = regexp.MustCompile("^" + VersionRegexpRaw + "$")
+}
+
+// NewVersion parses the given version and returns a new
+// Version.
+func NewVersion(v string) (*Version, error) {
+	matches := versionRegexp.FindStringSubmatch(v)
+	if matches == nil {
+		return nil, fmt.Errorf("Malformed version: %s", v)
+	}
+	segmentsStr := strings.Split(matches[1], ".")
+	segments := make([]int64, len(segmentsStr))
+	si := 0
+	for i, str := range segmentsStr {
+		val, err := strconv.ParseInt(str, 10, 64)
+		if err != nil {
+			return nil, fmt.Errorf(
+				"Error parsing version: %s", err)
+		}
+
+		segments[i] = int64(val)
+		si++
+	}
+
+	// Even though we could support more than three segments, if we
+	// got less than three, pad it with 0s. This is to cover the basic
+	// default usecase of semver, which is MAJOR.MINOR.PATCH at the minimum
+	for i := len(segments); i < 3; i++ {
+		segments = append(segments, 0)
+	}
+
+	return &Version{
+		metadata: matches[7],
+		pre:      matches[4],
+		segments: segments,
+		si:       si,
+	}, nil
+}
+
+// Must is a helper that wraps a call to a function returning (*Version, error)
+// and panics if error is non-nil.
+func Must(v *Version, err error) *Version {
+	if err != nil {
+		panic(err)
+	}
+
+	return v
+}
+
+// Compare compares this version to another version. This
+// returns -1, 0, or 1 if this version is smaller, equal,
+// or larger than the other version, respectively.
+//
+// If you want boolean results, use the LessThan, Equal,
+// or GreaterThan methods.
+func (v *Version) Compare(other *Version) int {
+	// A quick, efficient equality check
+	if v.String() == other.String() {
+		return 0
+	}
+
+	segmentsSelf := v.Segments64()
+	segmentsOther := other.Segments64()
+
+	// If the segments are the same, we must compare on prerelease info
+	if reflect.DeepEqual(segmentsSelf, segmentsOther) {
+		preSelf := v.Prerelease()
+		preOther := other.Prerelease()
+		if preSelf == "" && preOther == "" {
+			return 0
+		}
+		if preSelf == "" {
+			return 1
+		}
+		if preOther == "" {
+			return -1
+		}
+
+		return comparePrereleases(preSelf, preOther)
+	}
+
+	// Get the highest specificity (hS), or if they're equal, just use segmentSelf length
+	lenSelf := len(segmentsSelf)
+	lenOther := len(segmentsOther)
+	hS := lenSelf
+	if lenSelf < lenOther {
+		hS = lenOther
+	}
+	// Compare the segments
+	// Because a constraint could have more/less specificity than the version it's
+	// checking, we need to account for a lopsided or jagged comparison
+	for i := 0; i < hS; i++ {
+		if i > lenSelf-1 {
+			// This means Self had the lower specificity
+			// Check to see if the remaining segments in Other are all zeros
+			if !allZero(segmentsOther[i:]) {
+				// if not, it means that Other has to be greater than Self
+				return -1
+			}
+			break
+		} else if i > lenOther-1 {
+			// this means Other had the lower specificity
+			// Check to see if the remaining segments in Self are all zeros -
+			if !allZero(segmentsSelf[i:]) {
+				//if not, it means that Self has to be greater than Other
+				return 1
+			}
+			break
+		}
+		lhs := segmentsSelf[i]
+		rhs := segmentsOther[i]
+		if lhs == rhs {
+			continue
+		} else if lhs < rhs {
+			return -1
+		}
+		// Otherwis, rhs was > lhs, they're not equal
+		return 1
+	}
+
+	// if we got this far, they're equal
+	return 0
+}
+
+func allZero(segs []int64) bool {
+	for _, s := range segs {
+		if s != 0 {
+			return false
+		}
+	}
+	return true
+}
+
+func comparePart(preSelf string, preOther string) int {
+	if preSelf == preOther {
+		return 0
+	}
+
+	// if a part is empty, we use the other to decide
+	if preSelf == "" {
+		_, notIsNumeric := strconv.ParseInt(preOther, 10, 64)
+		if notIsNumeric == nil {
+			return -1
+		}
+		return 1
+	}
+
+	if preOther == "" {
+		_, notIsNumeric := strconv.ParseInt(preSelf, 10, 64)
+		if notIsNumeric == nil {
+			return 1
+		}
+		return -1
+	}
+
+	if preSelf > preOther {
+		return 1
+	}
+
+	return -1
+}
+
+func comparePrereleases(v string, other string) int {
+	// the same pre release!
+	if v == other {
+		return 0
+	}
+
+	// split both pre releases for analyse their parts
+	selfPreReleaseMeta := strings.Split(v, ".")
+	otherPreReleaseMeta := strings.Split(other, ".")
+
+	selfPreReleaseLen := len(selfPreReleaseMeta)
+	otherPreReleaseLen := len(otherPreReleaseMeta)
+
+	biggestLen := otherPreReleaseLen
+	if selfPreReleaseLen > otherPreReleaseLen {
+		biggestLen = selfPreReleaseLen
+	}
+
+	// loop for parts to find the first difference
+	for i := 0; i < biggestLen; i = i + 1 {
+		partSelfPre := ""
+		if i < selfPreReleaseLen {
+			partSelfPre = selfPreReleaseMeta[i]
+		}
+
+		partOtherPre := ""
+		if i < otherPreReleaseLen {
+			partOtherPre = otherPreReleaseMeta[i]
+		}
+
+		compare := comparePart(partSelfPre, partOtherPre)
+		// if parts are equals, continue the loop
+		if compare != 0 {
+			return compare
+		}
+	}
+
+	return 0
+}
+
+// Equal tests if two versions are equal.
+func (v *Version) Equal(o *Version) bool {
+	return v.Compare(o) == 0
+}
+
+// GreaterThan tests if this version is greater than another version.
+func (v *Version) GreaterThan(o *Version) bool {
+	return v.Compare(o) > 0
+}
+
+// LessThan tests if this version is less than another version.
+func (v *Version) LessThan(o *Version) bool {
+	return v.Compare(o) < 0
+}
+
+// Metadata returns any metadata that was part of the version
+// string.
+//
+// Metadata is anything that comes after the "+" in the version.
+// For example, with "1.2.3+beta", the metadata is "beta".
+func (v *Version) Metadata() string {
+	return v.metadata
+}
+
+// Prerelease returns any prerelease data that is part of the version,
+// or blank if there is no prerelease data.
+//
+// Prerelease information is anything that comes after the "-" in the
+// version (but before any metadata). For example, with "1.2.3-beta",
+// the prerelease information is "beta".
+func (v *Version) Prerelease() string {
+	return v.pre
+}
+
+// Segments returns the numeric segments of the version as a slice of ints.
+//
+// This excludes any metadata or pre-release information. For example,
+// for a version "1.2.3-beta", segments will return a slice of
+// 1, 2, 3.
+func (v *Version) Segments() []int {
+	segmentSlice := make([]int, len(v.segments))
+	for i, v := range v.segments {
+		segmentSlice[i] = int(v)
+	}
+	return segmentSlice
+}
+
+// Segments64 returns the numeric segments of the version as a slice of int64s.
+//
+// This excludes any metadata or pre-release information. For example,
+// for a version "1.2.3-beta", segments will return a slice of
+// 1, 2, 3.
+func (v *Version) Segments64() []int64 {
+	return v.segments
+}
+
+// String returns the full version string included pre-release
+// and metadata information.
+func (v *Version) String() string {
+	var buf bytes.Buffer
+	fmtParts := make([]string, len(v.segments))
+	for i, s := range v.segments {
+		// We can ignore err here since we've pre-parsed the values in segments
+		str := strconv.FormatInt(s, 10)
+		fmtParts[i] = str
+	}
+	fmt.Fprintf(&buf, strings.Join(fmtParts, "."))
+	if v.pre != "" {
+		fmt.Fprintf(&buf, "-%s", v.pre)
+	}
+	if v.metadata != "" {
+		fmt.Fprintf(&buf, "+%s", v.metadata)
+	}
+
+	return buf.String()
+}

vendor/github.com/hashicorp/go-version/version_collection.go

@@ -0,0 +1,17 @@
+package version
+
+// Collection is a type that implements the sort.Interface interface
+// so that versions can be sorted.
+type Collection []*Version
+
+func (v Collection) Len() int {
+	return len(v)
+}
+
+func (v Collection) Less(i, j int) bool {
+	return v[i].LessThan(v[j])
+}
+
+func (v Collection) Swap(i, j int) {
+	v[i], v[j] = v[j], v[i]
+}