deploy: ApplyParams: do not write params.env if there are no updates (o…

…pendatahub-io#1186)

Optimize file operations, do not rewrite params.env on every
reconcile if no updates for it. In practice updates happen only on
the first run.

Since updates happen in 2 loops, move actual update to own function
which returns "number of updates" (actually 0 or 1, so acts as
boolean) and use bitwise operations to accumulate updates for every
field.

It could be possible to use global boolean flag, but since it
requires to be initiated before the loops and set when updates
happen, the function should be guarded with mutex. Otherwise "true"
value from one invocation can be reset to "false" by the next
invocation".

Signed-off-by: Yauheni Kaliuta <[email protected]>
(cherry picked from commit 450e19f)

pkg/deploy/envParams.go

@@ -53,6 +53,17 @@ func writeParamsToTmp(params map[string]string, tmpDir string) (string, error) {
 	return tmp.Name(), nil
 }
 
+// updateMap returns the number of updates made (it operates on 1 field, so 0 or 1 only).
+func updateMap(m *map[string]string, key, val string) int {
+	old := (*m)[key]
+	if old == val {
+		return 0
+	}
+
+	(*m)[key] = val
+	return 1
+}
+
 /*
 overwrite values in components' manifests params.env file
 This is useful for air gapped cluster
@@ -75,22 +86,30 @@ func ApplyParams(componentPath string, imageParamsMap map[string]string, extraPa
 		return err
 	}
 
+	// will be used as a boolean (0 or non-0) and accumulate result of updates of every field
+	// Could use sum, but safe from hypothetically integer overflow
+	updated := 0
+
 	// 1. Update images with env variables
 	// e.g "odh-kuberay-operator-controller-image": "RELATED_IMAGE_ODH_KUBERAY_OPERATOR_CONTROLLER_IMAGE",
 	for i := range paramsEnvMap {
 		relatedImageValue := os.Getenv(imageParamsMap[i])
 		if relatedImageValue != "" {
-			paramsEnvMap[i] = relatedImageValue
+			updated |= updateMap(&paramsEnvMap, i, relatedImageValue)
 		}
 	}
 
 	// 2. Update other fileds with extraParamsMap which are not carried from component
 	for _, extraParamsMap := range extraParamsMaps {
 		for eKey, eValue := range extraParamsMap {
-			paramsEnvMap[eKey] = eValue
+			updated |= updateMap(&paramsEnvMap, eKey, eValue)
 		}
 	}
 
+	if updated == 0 {
+		return nil
+	}
+
 	tmp, err := writeParamsToTmp(paramsEnvMap, componentPath)
 	if err != nil {
 		return err