Export the Praefect version running

Praefect didn't expose the version running, which makes debugging
harder. This change follows conventions set by Gitaly.

A few ways of exposing the version are implemented:
1. Through the `-version` flag
2. Logging the version at boot of the server
3. A prometheus metric, the metric is stale, but the labels are not

Closes https://gitlab.com/gitlab-org/gitaly/issues/1499

1 files changed, 22 insertions, 0 deletions

diff --git a/internal/praefect/version.go b/internal/praefect/version.go
new file mode 100644
index 000000000..25758f35a
--- /dev/null
+++ b/internal/praefect/version.go
@@ -0,0 +1,22 @@
+package praefect
+
+import (
+	"fmt"
+
+	"gitlab.com/gitlab-org/gitaly/internal/version"
+)
+
+// GetVersionString returns a standard version header
+func GetVersionString() string {
+	return fmt.Sprintf("Praefect, version %v", version.GetVersion())
+}
+
+// GetVersion returns the semver compatible version number
+func GetVersion() string {
+	return version.GetVersion()
+}
+
+// GetBuildTime returns the time at which the build took place
+func GetBuildTime() string {
+	return version.GetBuildTime()
+}