contribs: include try.go to enable DB retries

Include try.go package to enable retrying of DB connections after failure.

contrib/include-package-try/main.go

@@ -0,0 +1,38 @@
+// Sourced from https://github.com/matryer/try
+
+package try
+
+import "errors"
+
+// MaxRetries is the maximum number of retries before bailing.
+var MaxRetries = 10
+
+var errMaxRetriesReached = errors.New("exceeded retry limit")
+
+// Func represents functions that can be retried.
+type Func func(attempt int) (retry bool, err error)
+
+// Do keeps trying the function until the second argument
+// returns false, or no error is returned.
+func Do(fn Func) error {
+	var err error
+	var cont bool
+	attempt := 1
+	for {
+		cont, err = fn(attempt)
+		if !cont || err == nil {
+			break
+		}
+		attempt++
+		if attempt > MaxRetries {
+			return errMaxRetriesReached
+		}
+	}
+	return err
+}
+
+// IsMaxRetries checks whether the error is due to hitting the
+// maximum number of retries or not.
+func IsMaxRetries(err error) bool {
+	return err == errMaxRetriesReached
+}