pkg/ready: Make set/unset idempotent (#1761)

* pkg/ready: Make set/unset idempotent

Fixes #1760

Author: djzager

CHANGELOG.md

@@ -8,6 +8,7 @@
 ### Changed
 
 - **Breaking change:** CSV config field `role-path` is now `role-paths` and takes a list of strings. Users can now specify multiple `Role` and `ClusterRole` manifests using `role-paths`. ([#1704](https://github.com/operator-framework/operator-sdk/pull/1704))
+- Make `ready` package idempotent. Now, a user can call `Set()` or `Unset()` to set the operator's readiness without knowing the current state. ([#1761](https://github.com/operator-framework/operator-sdk/pull/1761))
 
 ### Deprecated
 

pkg/ready/ready.go

@@ -18,6 +18,7 @@ import (
 	"os"
 )
 
+// FileName represent the full path to the file for determining ready status
 const FileName = "/tmp/operator-sdk-ready"
 
 // Ready holds state about whether the operator is ready and communicates that
@@ -47,12 +48,18 @@ type fileReady struct{}
 func (r fileReady) Set() error {
 	f, err := os.Create(FileName)
 	if err != nil {
+		if os.IsExist(err) {
+			return nil
+		}
 		return err
 	}
 	return f.Close()
 }
 
 // Unset removes the file on disk that was created by Set().
 func (r fileReady) Unset() error {
+	if _, err := os.Stat(FileName); os.IsNotExist(err) {
+		return nil
+	}
 	return os.Remove(FileName)
 }

pkg/ready/ready_test.go

@@ -31,6 +31,12 @@ func TestFileReady(t *testing.T) {
 		t.Errorf("Did not find expected file at %s: %v", FileName, err)
 	}
 
+	// Should be safe to set multiple times
+	err = r.Set()
+	if err != nil {
+		t.Errorf("Failed to set ready file when it already exists: %v", err)
+	}
+
 	err = r.Unset()
 	if err != nil {
 		t.Errorf("Could not unset ready file: %v", err)
@@ -43,4 +49,9 @@ func TestFileReady(t *testing.T) {
 	if !os.IsNotExist(err) {
 		t.Errorf("Error determining if file still exists at %s: %v", FileName, err)
 	}
+
+	err = r.Unset()
+	if err != nil {
+		t.Errorf("Could not unset ready file when already removed: %v", err)
+	}
 }