[Tour of Beam] Learning content for "Final challenge" module (#26861)

* add final challenge

* correct examples

* changge

* correct golang

* correct example hint

* correct examples and add golang example

* delete whitespace

* delete whitespace

* add file tag

* correct final challenge

* fixing incorrect tags and names

* minor formatting

* fixing example formatting

* correct challenge

* correct whitespace

* change final-challenge-2

* correct imports

* fix splittable unit id

* formatting

* format change

* formatting

* fixing template

* temp fix of url

* backend urls fix

* restore backend urls

* change

* remove window

---------

Co-authored-by: mende1esmende1es <mende1esmende1es@gmail.cp>
Co-authored-by: Oleh Borysevych <oleg.borisevich@akvelon.com>

learning/tour-of-beam/learning-content/content-info.yaml

@@ -31,4 +31,5 @@ content:
   - io
   - splittable-dofn
   - cross-language
-
+  - final-challenge
+

learning/tour-of-beam/learning-content/final-challenge/final-challenge-1/description.md

@@ -0,0 +1,27 @@
+<!--
+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.
+-->
+### Final challenge 1
+
+You’re given a csv file with purchase transactions. Write a Beam pipeline to prepare a report every 30 seconds. The report needs to be created only for transactions where quantity is more than 20.
+
+Report should consist of two files named "**price_more_than_10.txt**" and "**price_less_than_10.txt**":
+
+* Total transactions amount grouped by **ProductNo** for products with **price** greater than 10
+* Total transactions amount grouped by **ProductNo** for products with **price** less than 10
+
+Example rows from input file:
+
+| TransactionNo | Date      | ProductNo | ProductName                         | Price | Quantity | CustomerNo | Country        |
+|---------------|-----------|-----------|-------------------------------------|-------|----------|------------|----------------|
+| 581482        | 12/9/2019 | 22485     | Set Of 2 Wooden Market Crates       | 21    | 47       | 17490      | United Kingdom |
+| 581475        | 12/9/2019 | 22596     | Christmas Star Wish List Chalkboard | 10.65 | 36       | 13069      | United Kingdom |
+| 581475        | 12/9/2019 | 23235     | Storage Tin Vintage Leaf            | 11.53 | 12       | 13069      | United Kingdom |

learning/tour-of-beam/learning-content/final-challenge/final-challenge-1/go-challenge/main.go

@@ -0,0 +1,65 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+// beam-playground:
+//   name: FinalChallenge1
+//   description: Final challenge 1.
+//   multifile: true
+//   files:
+//     - name: input.csv
+//   context_line: 54
+//   categories:
+//     - Quickstart
+//   complexity: ADVANCED
+//   tags:
+//     - hellobeam
+
+package main
+
+import (
+	"context"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/io/textio"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/x/beamx"
+	"log"
+)
+
+type Transaction struct {
+	ID          int64
+	Date        string
+	ProductID   string
+	ProductName string
+	Price       float64
+	Quantity    int64
+	CustomerID  int64
+	Country     string
+}
+
+func main() {
+	beam.Init()
+	p := beam.NewPipeline()
+	s := p.Root()
+
+	file := textio.Read(s, "input.csv")
+
+	textio.Write(s, "price_less_than_10.txt", file)
+
+	if err := beamx.Run(context.Background(), p); err != nil {
+		log.Fatalf("Failed to execute job: %v", err)
+	}
+}

learning/tour-of-beam/learning-content/final-challenge/final-challenge-1/go-solution/main.go

@@ -0,0 +1,150 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+// beam-playground:
+//   name: FinalSolution1
+//   description: Final challenge solution 1.
+//   multifile: true
+//   files:
+//     - name: input.csv
+//   context_line: 54
+//   categories:
+//     - Quickstart
+//   complexity: ADVANCED
+//   tags:
+//     - hellobeam
+
+package main
+
+import (
+	"context"
+	"fmt"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/graph/window"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/graph/window/trigger"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/io/textio"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/transforms/filter"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/transforms/stats"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/x/beamx"
+	"log"
+	"strconv"
+	"strings"
+	"time"
+)
+
+type Transaction struct {
+	ID          int64
+	Date        string
+	ProductID   string
+	ProductName string
+	Price       float64
+	Quantity    int64
+	CustomerID  int64
+	Country     string
+}
+
+func main() {
+	ctx := context.Background()
+
+	beam.Init()
+	p := beam.NewPipeline()
+	s := p.Root()
+
+	file := textio.Read(s, "input.csv")
+
+	transactions := getTransactions(s, file)
+
+	trigger := trigger.AfterEndOfWindow().
+		EarlyFiring(trigger.AfterProcessingTime().
+			PlusDelay(5 * time.Second)).
+		LateFiring(trigger.Repeat(trigger.AfterCount(1)))
+
+	fixedWindowedItems := beam.WindowInto(s, window.NewFixedWindows(30*time.Second), transactions,
+		beam.Trigger(trigger),
+		beam.AllowedLateness(30*time.Minute),
+		beam.PanesDiscard(),
+	)
+
+	filtered := filtering(s, fixedWindowedItems)
+
+	result := getPartition(s, filtered)
+
+	biggerThan10 := sumCombine(s, mapIdWithPrice(s, result[0]))
+	textio.Write(s, "price_more_than_10.txt", convertToString(s, biggerThan10))
+
+	smallerThan10 := sumCombine(s, mapIdWithPrice(s, result[1]))
+	textio.Write(s, "price_less_than_10.txt", convertToString(s, smallerThan10))
+
+	if err := beamx.Run(ctx, p); err != nil {
+		log.Fatalf("Failed to execute job: %v", err)
+	}
+}
+
+func getTransactions(s beam.Scope, input beam.PCollection) beam.PCollection {
+	return beam.ParDo(s, func(line string, emit func(transaction Transaction)) {
+		csv := strings.Split(line, ",")
+
+		if csv[0] != "TransactionNo" {
+			id, _ := strconv.ParseInt(csv[0], 10, 64)
+			price, _ := strconv.ParseFloat(csv[4], 64)
+			quantity, _ := strconv.ParseInt(csv[5], 10, 64)
+			customerID, _ := strconv.ParseInt(csv[6], 10, 64)
+			emit(Transaction{
+				ID:          id,
+				Date:        csv[1],
+				ProductID:   csv[2],
+				ProductName: csv[3],
+				Price:       price,
+				Quantity:    quantity,
+				CustomerID:  customerID,
+				Country:     csv[7],
+			})
+		}
+	}, input)
+}
+
+func getPartition(s beam.Scope, input beam.PCollection) []beam.PCollection {
+	return beam.Partition(s, 2, func(element Transaction) int {
+		if element.Price >= 10 {
+			return 0
+		}
+		return 1
+	}, input)
+}
+
+func convertToString(s beam.Scope, input beam.PCollection) beam.PCollection {
+	return beam.ParDo(s, func(product string, sum float64, emit func(string)) {
+		emit(fmt.Sprint("product: ", product, " , sum: ", sum))
+	}, input)
+}
+
+func filtering(s beam.Scope, input beam.PCollection) beam.PCollection {
+	return filter.Include(s, input, func(element Transaction) bool {
+		return element.Quantity >= 20
+	})
+}
+
+func mapIdWithPrice(s beam.Scope, input beam.PCollection) beam.PCollection {
+	return beam.ParDo(s, func(element Transaction, emit func(string, float64)) {
+		emit(element.ProductID, element.Price)
+	}, input)
+}
+
+func sumCombine(s beam.Scope, input beam.PCollection) beam.PCollection {
+	return stats.SumPerKey(s, input)
+}