main: Add -version

Give callers an easy way to extract both the plugin version and the
dependency versions.  With this commit:

  $ ./terraform-provider-libvirt -version
  ./terraform-provider-libvirt 48adac3-dirty
  Compiled against library: libvirt 3.9.0
  Using library: libvirt 3.9.0
  Running hypervisor: QEMU 2.9.0
  Running against daemon: 3.9.0

The details are very similar to:

  $ virsh version --daemon
  Compiled against library: libvirt 3.9.0
  Using library: libvirt 3.9.0
  Using API: QEMU 3.9.0
  Running hypervisor: QEMU 2.9.0
  Running against daemon: 3.9.0

except the Go bindings do not currently expose the API version [1].
I've submitted a patch to libvirt-go adding ParseVersion there.  But
until then, carrying our own parseVersion shouldn't be too much
trouble.

Passing an empty string to NewConnect ends up passing a nil pointer
through to virConnect [2], which will give us libvirt's internal
default URI logic [3,4].

I hunted around for a way to expose the version information in
Terraform.  Currently:

  $ cat main.tf
  provider "libvirt" {
    uri = "qemu:///system"
  }
  $ terraform version
  Terraform v0.11.8
  + provider.libvirt (unversioned)

but the RPC API is not particularly clear to me, and the versions
there may be extracted from plugin filenames and not from RPC calls.

[1]: https://libvirt.org/git/?p=libvirt-go.git;a=blob;f=connect.go;h=8cc7cc771f7d258400175df47fcc8b3779ef4930;hb=9c5bdce3c18faad94cb383e7ec42f5122a8c7fa1#l313
[2]: https://libvirt.org/git/?p=libvirt-go.git;a=blob;f=connect.go;h=8cc7cc771f7d258400175df47fcc8b3779ef4930;hb=9c5bdce3c18faad94cb383e7ec42f5122a8c7fa1#l322
[3]: https://libvirt.org/html/libvirt-libvirt-host.html#virConnectOpen
[4]: https://libvirt.org/uri.html#URI_default

.github/ISSUE_TEMPLATE.md

@@ -5,15 +5,22 @@
 ``` openSUSE 42.2/ Centos7/ Ubuntu.. ```
 
 ### Terraform Version Report
-(Provided by running `terraform -v`.)
 
-### Libvirt version
+```sh
+terraform -v
+```
 
-```virsh --version```
+### Provider and libvirt versions
 
-### terraform-provider-libvirt plugin version (git-hash)
+```sh
+terraform-provider-libvirt -version
+```
 
-``` git log```
+If that gives you "was not built correctly", get the Git commit hash from your local provider repository:
+
+```sh
+git describe --always --abbrev=40 --dirty
+```
 ___
 # Description of Issue/Question
 

Makefile

@@ -1,13 +1,15 @@
+LDFLAGS += -X main.version=$$(git describe --always --abbrev=40 --dirty)
+
 default: build
 
 build: gofmtcheck golint vet
- go build
+ go build -ldflags "${LDFLAGS}"
 
 install:
  go install
 
 test:
- go test -v -covermode=count -coverprofile=profile.cov ./libvirt
+ go test -v -covermode=count -coverprofile=profile.cov . ./libvirt
 
 testacc:
  ./travis/run-tests-acceptance

main.go

@@ -1,20 +1,83 @@
 package main
 
 import (
- "github.com/dmacvicar/terraform-provider-libvirt/libvirt"
- "github.com/hashicorp/terraform/plugin"
+ "flag"
+ "fmt"
+ "io"
+ "log"
  "math/rand"
+ "os"
  "time"
+
+ "github.com/dmacvicar/terraform-provider-libvirt/libvirt"
+ "github.com/hashicorp/terraform/plugin"
+ libvirtgo "github.com/libvirt/libvirt-go"
 )
 
+var version = "was not built correctly" // set via the Makefile
+
 func main() {
+ versionFlag := flag.Bool("version", false, "print version information and exit")
+ flag.Parse()
+ if *versionFlag {
+ err := printVersion(os.Stdout)
+ if err != nil {
+ log.Fatal(err)
+ }
+ os.Exit(0)
+ }
+
  defer libvirt.CleanupLibvirtConnections()
 
  plugin.Serve(&plugin.ServeOpts{
  ProviderFunc: libvirt.Provider,
  })
 }
 
+func printVersion(writer io.Writer) error {
+ fmt.Fprintf(writer, "%s %s\n", os.Args[0], version)
+
+ fmt.Fprintf(writer, "Compiled against library: libvirt %s\n", parseVersion(libvirtgo.VERSION_NUMBER))
+
+ libvirtVersion, err := libvirtgo.GetVersion()
+ if err != nil {
+ return err
+ }
+ fmt.Fprintf(writer, "Using library: libvirt %s\n", parseVersion(libvirtVersion))
+
+ conn, err := libvirtgo.NewConnect("")
+ if err != nil {
+ return err
+ }
+ defer conn.Close()
+
+ hvType, err := conn.GetType()
+ if err != nil {
+ return err
+ }
+ libvirtVersion, err = conn.GetVersion()
+ if err != nil {
+ return err
+ }
+ fmt.Fprintf(writer, "Running hypervisor: %s %s\n", hvType, parseVersion(libvirtVersion))
+
+ libvirtVersion, err = conn.GetLibVersion()
+ if err != nil {
+ return err
+ }
+ fmt.Fprintf(writer, "Running against daemon: %s\n", parseVersion(libvirtVersion))
+
+ return nil
+}
+
+func parseVersion(version uint32) string {
+ release := version % 1000
+ version /= 1000
+ minor := version % 1000
+ major := version / 1000
+ return fmt.Sprintf("%d.%d.%d", major, minor, release)
+}
+
 func init() {
  rand.Seed(time.Now().UTC().UnixNano())
 }

main_test.go

@@ -0,0 +1,21 @@
+package main
+
+import (
+ "bytes"
+ "regexp"
+ "testing"
+)
+
+func TestPrintVersion(t *testing.T) {
+ buf := &bytes.Buffer{}
+ err := printVersion(buf)
+ if err != nil {
+ t.Fatal(err)
+ }
+ output := buf.Bytes()
+
+ re := regexp.MustCompile("^.*terraform-provider-libvirt.test was not built correctly\\nCompiled against library: libvirt [0-9.]*\\nUsing library: libvirt [0-9.]*\\nRunning hypervisor: .* [0-9.]*\\nRunning against daemon: [0-9.]*\\n$")
+ if !re.Match(output) {
+ t.Fatalf("unexpected output:\n%q", string(output))
+ }
+}