Add support for try and undo allocate

pkg/quotaplugins/quota-forest/quota-manager/README.md

@@ -188,6 +188,12 @@ A summary of the API interface to the Quota Manager follows.
 - Forest Updates
   - refresh (effect) updates from caches
     - `UpdateForest(forestName)`
+- Undo consumer allocation: Two calls are provided to try to allocate a consumer, and if unaccepted, to undo the effect of the allocation trial. If the trial is accepted, no further action is needed. Otherwise, the undo has to be called right after the try allocation, without making any calls to change the trees or allocate/deallocate consumers. These operations are intended only during Normal mode.
+(Note: This design pattern puts the burden on the caller of the quota manager to make sure that TryAllocate() and UndoAllocate() are run in an atomic fashion. So, a lock is needed for that purpose. An example is provided in the TestQuotaManagerParallelTryUndoAllocation() in [quotamanagerundo_test.go](quota/quotamanagerundo_test.go))
+  - `TryAllocate(treeName, consumerID)`
+  - `UndoAllocate(treeName, consumerID)`
+  - `TryAllocateForest(forestName, consumerID)`
+  - `UndoAllocateForest(forestName, consumerID)`
 
 Examples of using the Quota Manager in the case of a [single tree](demos/manager/tree/demo.go) and a [forest](demos/manager/forest/demo.go) are provided.
 

pkg/quotaplugins/quota-forest/quota-manager/demos/undo/forest/demo.go

@@ -0,0 +1,122 @@
+/*
+Copyright 2023 The Multi-Cluster App Dispatcher Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+
+	"github.com/project-codeflare/multi-cluster-app-dispatcher/pkg/quotaplugins/quota-forest/quota-manager/quota"
+	"k8s.io/klog/v2"
+)
+
+func main() {
+	klog.InitFlags(nil)
+	flag.Set("v", "4")
+	flag.Set("skip_headers", "true")
+	klog.SetOutput(os.Stdout)
+	flag.Parse()
+	defer klog.Flush()
+
+	fmt.Println("Demo of allocation and de-allocation of consumers on a forest using the quota manager.")
+	fmt.Println()
+	prefix := "../../../samples/forest/"
+	indent := "===> "
+	forestName := "Context-Service"
+	treeNames := []string{"ContextTree", "ServiceTree"}
+
+	// create a quota manager
+	fmt.Println(indent + "Creating quota manager ... " + "\n")
+	quotaManager := quota.NewManager()
+	quotaManager.SetMode(quota.Normal)
+	fmt.Println(quotaManager.GetModeString())
+	fmt.Println()
+
+	//	create multiple trees
+	fmt.Println(indent + "Creating multiple trees ..." + "\n")
+	for _, treeName := range treeNames {
+		fName := prefix + treeName + ".json"
+		fmt.Printf("Tree file name: %s\n", fName)
+		jsonTree, err := os.ReadFile(fName)
+		if err != nil {
+			fmt.Printf("error reading quota tree file: %s", fName)
+			return
+		}
+		_, err = quotaManager.AddTreeFromString(string(jsonTree))
+		if err != nil {
+			fmt.Printf("error adding tree %s: %v", treeName, err)
+			return
+		}
+	}
+
+	// create forest
+	fmt.Println(indent + "Creating forest " + forestName + " ..." + "\n")
+	quotaManager.AddForest(forestName)
+	for _, treeName := range treeNames {
+		quotaManager.AddTreeToForest(forestName, treeName)
+	}
+	fmt.Println(quotaManager)
+
+	//	create consumer jobs
+	fmt.Println(indent + "Allocating consumers on forest ..." + "\n")
+	jobs := []string{"job1", "job2", "job3", "job4", "job5"}
+	for _, job := range jobs {
+
+		// create consumer info
+		fName := prefix + job + ".json"
+		fmt.Printf("Consumer file name: %s\n", fName)
+		consumerInfo, err := quota.NewConsumerInfoFromFile(fName)
+		if err != nil {
+			fmt.Printf("error reading consumer file: %s \n", fName)
+			continue
+		}
+		consumerID := consumerInfo.GetID()
+
+		// add consumer info to quota manager
+		quotaManager.AddConsumer(consumerInfo)
+
+		// allocate forest consumer instance of the consumer info
+		if job == "job4" {
+			_, err = quotaManager.TryAllocateForest(forestName, consumerID)
+			if err != nil {
+				fmt.Printf("error allocating consumer: %v \n", err)
+			}
+			err = quotaManager.UndoAllocateForest(forestName, "job-4")
+			if err != nil {
+				fmt.Printf("error undoing allocation consumer: %v \n", err)
+			}
+			_, err = quotaManager.AllocateForest(forestName, consumerID)
+		} else {
+			_, err = quotaManager.AllocateForest(forestName, consumerID)
+		}
+
+		if err != nil {
+			fmt.Printf("error allocating consumer: %v \n", err)
+			quotaManager.RemoveConsumer((consumerID))
+			continue
+		}
+	}
+
+	// de-allocate consumers from forest
+	fmt.Println(indent + "De-allocating consumers from forest ..." + "\n")
+	for _, id := range quotaManager.GetAllConsumerIDs() {
+		quotaManager.DeAllocateForest(forestName, id)
+		quotaManager.RemoveConsumer(id)
+	}
+	fmt.Println()
+	fmt.Println(quotaManager)
+}

pkg/quotaplugins/quota-forest/quota-manager/demos/undo/tree/demo.go

@@ -0,0 +1,124 @@
+/*
+Copyright 2023 The Multi-Cluster App Dispatcher Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+
+	"github.com/project-codeflare/multi-cluster-app-dispatcher/pkg/quotaplugins/quota-forest/quota-manager/quota"
+	"github.com/project-codeflare/multi-cluster-app-dispatcher/pkg/quotaplugins/quota-forest/quota-manager/quota/core"
+	klog "k8s.io/klog/v2"
+)
+
+func main() {
+	klog.InitFlags(nil)
+	flag.Set("v", "4")
+	flag.Set("skip_headers", "true")
+	klog.SetOutput(os.Stdout)
+	flag.Parse()
+	defer klog.Flush()
+
+	prefix := "../../../samples/tree/"
+	treeFileName := prefix + "tree.json"
+	caFileName := prefix + "ca.json"
+	cbFileName := prefix + "cb.json"
+	ccFileName := prefix + "cc.json"
+	cdFileName := prefix + "cd.json"
+	ceFileName := prefix + "ce.json"
+
+	// create a quota manager
+	fmt.Println("==> Creating Quota Manager")
+	fmt.Println("**************************")
+	quotaManager := quota.NewManager()
+	treeJsonString, err := os.ReadFile(treeFileName)
+	if err != nil {
+		fmt.Printf("error reading quota tree file: %s", treeFileName)
+		return
+	}
+	quotaManager.SetMode(quota.Normal)
+
+	// add a quota tree from file
+	treeName, err := quotaManager.AddTreeFromString(string(treeJsonString))
+	if err != nil {
+		fmt.Printf("error adding tree %s: %v", treeName, err)
+		return
+	}
+
+	// allocate consumers
+	allocate(quotaManager, treeName, caFileName, false)
+	allocate(quotaManager, treeName, cbFileName, false)
+	allocate(quotaManager, treeName, ccFileName, false)
+
+	// try and undo allocation
+	allocate(quotaManager, treeName, cdFileName, true)
+	undoAllocate(quotaManager, treeName, cdFileName)
+
+	// allocate consumers
+	allocate(quotaManager, treeName, ceFileName, false)
+}
+
+// allocate consumer from file
+func allocate(quotaManager *quota.Manager, treeName string, consumerFileName string, try bool) {
+	consumerInfo := getConsumerInfo(consumerFileName)
+	if consumerInfo == nil {
+		fmt.Printf("error reading consumer file: %s", consumerFileName)
+		return
+	}
+	consumerID := consumerInfo.GetID()
+	fmt.Println("==> Allocating consumer " + consumerID)
+	fmt.Println("**************************")
+	quotaManager.AddConsumer(consumerInfo)
+
+	var allocResponse *core.AllocationResponse
+	var err error
+	if try {
+		allocResponse, err = quotaManager.TryAllocate(treeName, consumerID)
+	} else {
+		allocResponse, err = quotaManager.Allocate(treeName, consumerID)
+	}
+	if err != nil {
+		fmt.Printf("error allocating consumer: %v", err)
+		return
+	}
+	fmt.Println(allocResponse)
+	fmt.Println(quotaManager)
+}
+
+// undo most recent consumer allocation
+func undoAllocate(quotaManager *quota.Manager, treeName string, consumerFileName string) {
+	consumerInfo := getConsumerInfo(consumerFileName)
+	if consumerInfo == nil {
+		fmt.Printf("error reading consumer file: %s", consumerFileName)
+		return
+	}
+	consumerID := consumerInfo.GetID()
+	fmt.Println("==> Undo allocating consumer " + consumerID)
+	fmt.Println("**************************")
+	quotaManager.UndoAllocate(treeName, consumerID)
+	fmt.Println(quotaManager)
+}
+
+// get consumer info from yaml file
+func getConsumerInfo(consumerFileName string) *quota.ConsumerInfo {
+	consumerInfo, err := quota.NewConsumerInfoFromFile(consumerFileName)
+	if err != nil {
+		fmt.Printf("error reading consumer file: %s", consumerFileName)
+		return nil
+	}
+	return consumerInfo
+}

pkg/quotaplugins/quota-forest/quota-manager/quota/consumerinfo.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2022 The Multi-Cluster App Dispatcher Authors.
+Copyright 2022, 2023 The Multi-Cluster App Dispatcher Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -19,7 +19,7 @@ package quota
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"os"
 
 	"github.com/project-codeflare/multi-cluster-app-dispatcher/pkg/quotaplugins/quota-forest/quota-manager/quota/core"
 	"github.com/project-codeflare/multi-cluster-app-dispatcher/pkg/quotaplugins/quota-forest/quota-manager/quota/utils"
@@ -49,7 +49,7 @@ func NewConsumerInfo(consumerStruct utils.JConsumer) (*ConsumerInfo, error) {
 
 // NewConsumerInfoFromFile : create a new ConsumerInfo from Json file
 func NewConsumerInfoFromFile(consumerFileName string) (*ConsumerInfo, error) {
-	byteValue, err := ioutil.ReadFile(consumerFileName)
+	byteValue, err := os.ReadFile(consumerFileName)
 	if err != nil {
 		return nil, err
 	}

pkg/quotaplugins/quota-forest/quota-manager/quota/core/consumer.go

@@ -1,11 +1,11 @@
 /*
-Copyright 2022 The Multi-Cluster App Dispatcher Authors.
+Copyright 2022, 2023 The Multi-Cluster App Dispatcher Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 
-    http://www.apache.org/licenses/LICENSE-2.0
+	http://www.apache.org/licenses/LICENSE-2.0
 
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
@@ -119,6 +119,13 @@ func (c *Consumer) IsAllocated() bool {
 	return c.aNode != nil
 }
 
+// ByID implements sort.Interface based on the ID field.
+type ByID []*Consumer
+
+func (c ByID) Len() int           { return len(c) }
+func (c ByID) Less(i, j int) bool { return c[i].id < c[j].id }
+func (c ByID) Swap(i, j int)      { c[i], c[j] = c[j], c[i] }
+
 // String : a print out of the consumer
 func (c *Consumer) String() string {
 	var b bytes.Buffer

pkg/quotaplugins/quota-forest/quota-manager/quota/core/forestconsumer.go

@@ -1,11 +1,11 @@
 /*
-Copyright 2022 The Multi-Cluster App Dispatcher Authors.
+Copyright 2022, 2023 The Multi-Cluster App Dispatcher Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 
-    http://www.apache.org/licenses/LICENSE-2.0
+	http://www.apache.org/licenses/LICENSE-2.0
 
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
@@ -19,7 +19,7 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"os"
 
 	utils "github.com/project-codeflare/multi-cluster-app-dispatcher/pkg/quotaplugins/quota-forest/quota-manager/quota/utils"
 )
@@ -42,7 +42,7 @@ func NewForestConsumer(id string, consumers map[string]*Consumer) *ForestConsume
 
 // NewForestConsumerFromFile : create a forest consumer from JSON file
 func NewForestConsumerFromFile(consumerFileName string, resourceNames map[string][]string) (*ForestConsumer, error) {
-	byteValue, err := ioutil.ReadFile(consumerFileName)
+	byteValue, err := os.ReadFile(consumerFileName)
 	if err != nil {
 		return nil, err
 	}
@@ -108,7 +108,7 @@ func (fc *ForestConsumer) GetTreeConsumer(treeName string) *Consumer {
 	return fc.consumers[treeName]
 }
 
-//IsAllocated : is consumer allocated on all trees in the forest
+// IsAllocated : is consumer allocated on all trees in the forest
 func (fc *ForestConsumer) IsAllocated() bool {
 	for _, consumer := range fc.consumers {
 		if !consumer.IsAllocated() {