Case (II) - KisFlow-Golang Stream Real-Time Computing - Flow Parallel Operation

Github: https://github.com/aceld/kis-flow
Document: https://github.com/aceld/kis-flow/wiki

---

Part1-OverView
Part2.1-Project Construction / Basic Modules
Part2.2-Project Construction / Basic Modules
Part3-Data Stream
Part4-Function Scheduling
Part5-Connector
Part6-Configuration Import and Export
Part7-KisFlow Action
Part8-Cache/Params Data Caching and Data Parameters
Part9-Multiple Copies of Flow
Part10-Prometheus Metrics Statistics
Part11-Adaptive Registration of FaaS Parameter Types Based on Reflection

---

Case1-Quick Start
Case2-Flow Parallel Operation
Case3-Application of KisFlow in Multi-Goroutines
Case4-KisFlow in Message Queue (MQ) Applications

---

Download KisFlow Source

$go get github.com/aceld/kis-flow

KisFlow Developer Documentation

Source Code Example

https://github.com/aceld/kis-flow-usage/tree/main/8-connector

KisFlow Can Achieve the Combination of Two Flows via Connector

Using the combination of the following two flows, this introduction will cover the interface and usage of the Connector.

Data Flow Diagram

Case Introduction

Assume a student has four attributes:

Student ID: stu_id
Credit 1: score_1
Credit 2: score_2
Credit 3: score_3

Define Flow1: CalStuAvgScore-1-2 to calculate a student's average score of Credit 1 (score_1) and Credit 2 (score_2) (avg_score_1_2).
Define Flow2: CalStuAvgScore-3 to calculate a student's average score of Credit 3 (score_3) and avg_score_1_2, which is the average of Credit 1, Credit 2, and Credit 3. The average of Credit 1 and Credit 2 is provided by Flow1.

Flow1

Flow1 consists of 4 functions:

V (Function: VerifyStu) to verify the validity of StuId
C (Function: AvgStuScore12) to calculate the average score of Credit 1 and Credit 2
S (Function: SaveScoreAvg12) to store avg_score_1_2 in Redis
E (Function: PrintStuAvgScore) to print the average score of Credit 1 and Credit 2.

Flow2

Flow2 consists of 4 functions:

V (Function: VerifyStu) to verify the validity of StuId
L (Function: LoadScoreAvg12) to read the current student's average score of Credit 1 and Credit 2 (avg_score_1_2) calculated by Flow1
C (Function: AvgStuScore3) to calculate the average score of Credit 3 and the average score of Credit 1 and Credit 2
E (Function: PrintStuAvgScore) to print the average score of Credit 1, Credit 2, and Credit 3.

conf/func/func-AvgStuScore-3.yml

kistype: func
fname: AvgStuScore3
fmode: Calculate
source:
    name: SourceStuScore
    must:
        - stu_id

conf/func/func-LoadScoreAvg-1-2.yml

kistype: func
fname: LoadScoreAvg12
fmode: Load
source:
    name: SourceStuScore
    must:
        - stu_id
option:
    cname: Score12Cache

Basic Data Protocol

stu_proto.go

package main

type StuScore1_2 struct {
    StuId  int `json:"stu_id"`
    Score1 int `json:"score_1"`
    Score2 int `json:"score_2"`
}

type StuScoreAvg struct {
    StuId    int     `json:"stu_id"`
    AvgScore float64 `json:"avg_score"`
}

type StuScore3 struct {
    StuId      int     `json:"stu_id"`
    AvgScore12 float64 `json:"avg_score_1_2"` // score_1, score_2 avg
    Score3     int     `json:"score_3"`
}

Connector Init

The Connector defined in this project, Score12Cache, is a link resource associated with Redis. This Connector requires an initialization method for establishing a connection when KisFlow starts.

conn_init.go

package main

import (
    "context"
    "fmt"
    "github.com/aceld/kis-flow/kis"
    "github.com/aceld/kis-flow/log"
    "github.com/go-redis/redis/v8"
)

// type ConnInit func(conn Connector) error

func InitScore12Cache(connector kis.Connector) error {
    fmt.Println("===> Call Connector InitScore12Cache")

    // init Redis Conn Client
    rdb := redis.NewClient(&redis.Options{
        Addr:     connector.GetConfig().AddrString, // Redis-Server address
        Password: "",                               // password
        DB:       0,                                // select db
    })

    // Ping test
    pong, err := rdb.Ping(context.Background()).Result()
    if err != nil {
        log.Logger().ErrorF("Failed to connect to Redis: %v", err)
        return err
    }
    fmt.Println("Connected to Redis:", pong)

    // set rdb to connector
    connector.SetMetaData("rdb", rdb)

    return nil
}

Here, the successfully connected Redis instance is stored in the connector's cache variable "rdb."

    // set rdb to connector
    connector.SetMetaData("rdb", rdb)

FaaS Implementation

Function(V): VerifyStu

faas_stu_verify.go

package main

import (
    "context"
    "fmt"
    "github.com/aceld/kis-flow/kis"
    "github.com/aceld/kis-flow/serialize"
)

type VerifyStuIn struct {
    serialize.DefaultSerialize
    StuId int `json:"stu_id"`
}

func VerifyStu(ctx context.Context, flow kis.Flow, rows []*VerifyStuIn) error {
    fmt.Printf("->Call Func VerifyStu\n")

    for _, stu := range rows {
        // Filter out invalid data
        if stu.StuId < 0 || stu.StuId > 999 {
            // Terminate the current Flow process, subsequent functions of the current Flow will not be executed
            return flow.Next(kis.ActionAbort)
        }
    }

    return flow.Next(kis.ActionDataReuse)
}

VerifyStu() is used to validate data. If the data does not meet the requirements, the current data flow is terminated. Finally, the data is reused and passed to the next layer through flow.Next(kis.ActionDataReuse).

Function(C): AvgStuScore12

faas_avg_score_1_2.go

package main

import (
    "context"
    "fmt"
    "github.com/aceld/kis-flow/kis"
    "github.com/aceld/kis-flow/serialize"
)

type AvgStuScoreIn_1_2 struct {
    serialize.DefaultSerialize
    StuScore1_2
}

type AvgStuScoreOut_1_2 struct {
    serialize.DefaultSerialize
    StuScoreAvg
}

func AvgStuScore12(ctx context.Context, flow kis.Flow, rows []*AvgStuScoreIn_1_2) error {
    fmt.Printf("->Call Func AvgStuScore12\n")

    for _, row := range rows {

        out := AvgStuScoreOut_1_2{
            StuScoreAvg: StuScoreAvg{
                StuId:    row.StuId,
                AvgScore: float64(row.Score1+row.Score2) / 2,
            },
        }

        // Submit result data
        _ = flow.CommitRow(out)
    }

    return flow.Next()
}

AvgStuScore12() calculates the average score of score_1 and score_2, resulting in avg_score.

Function(S): SaveScoreAvg12

faas_save_score_avg_1_2.go

package main

import (
    "context"
    "fmt"
    "github.com/aceld/kis-flow/kis"
    "github.com/aceld/kis-flow/serialize"
    "github.com/go-redis/redis/v8"
    "strconv"
)

type SaveStuScoreIn struct {
    serialize.DefaultSerialize
    StuScoreAvg
}

func BatchSetStuScores(ctx context.Context, conn kis.Connector, rows []*SaveStuScoreIn) error {

    var rdb *redis.Client

    // Get Redis Client
    rdb = conn.GetMetaData("rdb").(*redis.Client)

    // Set data to redis
    pipe := rdb.Pipeline()

    for _, score := range rows {
        // make key
        key := conn.GetConfig().Key + strconv.Itoa(score.StuId)

        pipe.HMSet(context.Background(), key, map[string]interface{}{
            "avg_score": score.AvgScore,
        })
    }

    _, err := pipe.Exec(ctx)
    if err != nil {
        return err
    }

    return nil
}

func SaveScoreAvg12(ctx context.Context, flow kis.Flow, rows []*SaveStuScoreIn) error {
    fmt.Printf("->Call Func SaveScoreAvg12\n")

    conn, err := flow.GetConnector()
    if err != nil {
        fmt.Printf("SaveScoreAvg12(): GetConnector err = %s\n", err.Error())
        return err
    }

    if BatchSetStuScores(ctx, conn, rows) != nil {
        fmt.Printf("SaveScoreAvg12(): BatchSetStuScores err = %s\n", err.Error())
        return err
    }

    return flow.Next(kis.ActionDataReuse)
}

SaveScoreAvg12() stores the data in Redis through the bound Connector, using the key configured in the Connector. Finally, the source data is transparently transmitted to the next function.

Function(E): PrintStuAvgScore

faas_stu_score_avg_print.go

package main

import (
    "context"
    "fmt"
    "github.com/aceld/kis-flow/kis"
    "github.com/aceld/kis-flow/serialize"
)

type PrintStuAvgScoreIn struct {
    serialize.DefaultSerialize
    StuId    int     `json:"stu_id"`
    AvgScore float64 `json:"avg_score"`
}

func PrintStuAvgScore(ctx context.Context, flow kis.Flow, rows []*PrintStuAvgScoreIn) error {
    fmt.Printf("->Call Func PrintStuAvgScore, in Flow[%s]\n", flow.GetName())

    for _, row := range rows {
        fmt.Printf("stuid: [%+v], avg score: [%+v]\n", row.StuId, row.AvgScore)
    }

    return flow.Next()
}

PrintStuAvgScore() prints the average score of the current student.

Function(L): LoadScoreAvg12

faas_load_score_avg_1_2.go

package main

import (
    "context"
    "fmt"
    "github.com/aceld/kis-flow/kis"
    "github.com/aceld/kis-flow/serialize"
    "github.com/go-redis/redis/v8"
    "strconv"
)

type LoadStuScoreIn struct {
    serialize.DefaultSerialize
    StuScore3
}

type LoadStuScoreOut struct {
    serialize.DefaultSerialize
    StuScore3
}

func GetStuScoresByStuId(ctx context.Context, conn kis.Connector, stuId int) (float64, error) {

    var rdb *redis.Client

    // Get Redis Client
    rdb = conn.GetMetaData("rdb").(*redis.Client)

    // make key
    key := conn.GetConfig().Key + strconv.Itoa(stuId)

    // get data from redis
    result, err := rdb.HGetAll(ctx, key).Result()
    if err != nil {
        return 0, err
    }

    // get value
    avgScoreStr, ok := result["avg_score"]
    if !ok {
        return 0, fmt.Errorf("avg_score not found for stuId: %d", stuId)
    }

    // parse to float64
    avgScore, err := strconv.ParseFloat(avgScoreStr, 64)
    if err != nil {
        return 0, err
    }

    return avgScore, nil
}

func LoadScoreAvg12(ctx context.Context, flow kis.Flow, rows []*LoadStuScoreIn) error {
    fmt.Printf("->Call Func LoadScoreAvg12\n")

    conn, err := flow.GetConnector()
    if err != nil {
        fmt.Printf("LoadScoreAvg12(): GetConnector err = %s\n", err.Error())
        return err
    }

    for _, row := range rows {
        stuScoreAvg1_2, err := GetStuScoresByStuId(ctx, conn, row.StuId)
        if err != nil {
            fmt.Printf("LoadScoreAvg12(): GetStuScoresByStuId err = %s\n", err.Error())
            return err
        }

        out := LoadStuScoreOut{
            StuScore3: StuScore3{
                StuId:      row.StuId,
                Score3:     row.Score3,
                AvgScore12: stuScoreAvg1_2, // avg score of score1 and score2 (load from redis)
            },
        }

        // commit result
        _ = flow.CommitRow(out)
    }

    return flow.Next()
}

LoadScoreAvg12() reads the average score of score_1 and score_2 from Redis through the linked resource Redis of the bound Connector using the key configured in the Connector. It then sends the source data from upstream, along with the newly read average score of score1 and score2, to the next layer.

Function(C): AvgStuScore3

faas_stu_score_avg_3.go

package main

import (
    "context"
    "fmt"
    "github.com/aceld/kis-flow/kis"
    "github.com/aceld/kis-flow/serialize"
)

type AvgStuScore3In struct {
    serialize.DefaultSerialize
    StuScore3
}

type AvgStuScore3Out struct {
    serialize.DefaultSerialize
    StuScoreAvg
}

func AvgStuScore3(ctx context.Context, flow kis.Flow, rows []*AvgStuScore3In) error {
    fmt.Printf("->Call Func AvgStuScore3\n")

    for _, row := range rows {

        out := AvgStuScore3Out{
            StuScoreAvg: StuScoreAvg{
                StuId:    row.StuId,
                AvgScore: (float64(row.Score3) + row.AvgScore12*2) / 3,
            },
        }

        // Submit result data
        _ = flow.CommitRow(out)
    }

    return flow.Next()
}

AvgStuScore3() recalculates the average score of three scores by adding score_3 and the average score of score_1 and score_2, resulting in the final average score avg_score.

Register FaaS & CaaSInit/CaaS (Register Function/Connector)

main.go

func init() {
    // Register functions
    kis.Pool().FaaS("VerifyStu", VerifyStu)
    kis.Pool().FaaS("AvgStuScore12", AvgStuScore12)
    kis.Pool().FaaS("SaveScoreAvg12", SaveScoreAvg12)
    kis.Pool().FaaS("PrintStuAvgScore", PrintStuAvgScore)
    kis.Pool().FaaS("LoadScoreAvg12", LoadScoreAvg12)
    kis.Pool().FaaS("AvgStuScore3", AvgStuScore3)

    // Register connectors
    kis.Pool().CaaSInit("Score12Cache", InitScore12Cache)
}

Main Process

main.go

package main

import (
    "context"
    "github.com/aceld/kis-flow/file"
    "github.com/aceld/kis-flow/kis"
    "sync"
)

func RunFlowCalStuAvgScore12(ctx context.Context, flow kis.Flow) error {

    // Commit data
    _ = flow.CommitRow(`{"stu_id":101, "score_1":100, "score_2":90}`)
    _ = flow.CommitRow(`{"stu_id":102, "score_1":100, "score_2":80}`)

    // Run the flow
    if err := flow.Run(ctx); err != nil {
        return err
    }

    return nil
}

func RunFlowCalStuAvgScore3(ctx context.Context, flow kis.Flow) error {

    // Commit data
    _ = flow.CommitRow(`{"stu_id":101, "score_3": 80}`)
    _ = flow.CommitRow(`{"stu_id":102, "score_3": 70}`)

    // Run the flow
    if err := flow.Run(ctx); err != nil {
        return err
    }

    return nil
}

func main() {
    ctx := context.Background()

    // Load Configuration from file
    if err := file.ConfigImportYaml("conf/"); err != nil {
        panic(err)
    }

    var wg sync.WaitGroup
    wg.Add(2)

    go func() {
        // Run flow1 concurrently
        defer wg.Done()

        flow1 := kis.Pool().GetFlow("CalStuAvgScore12")
        if flow1 == nil {
            panic("flow1 is nil")
        }

        if err := RunFlowCalStuAvgScore12(ctx, flow1); err != nil {
            panic(err)
        }
    }()

    go func() {
        // Run flow2 concurrently
        defer wg.Done()

        flow2 := kis.Pool().GetFlow("CalStuAvgScore3")
        if flow2 == nil {
            panic("flow2 is nil")
        }

        if err := RunFlowCalStuAvgScore3(ctx, flow2); err != nil {
            panic(err)
        }
    }()

    wg.Wait()

    return
}

Two Goroutines are launched concurrently to execute Flow1 and Flow2, calculating the final average scores for student 101 and student 102.

Execution Results

===> Call Connector InitScore12Cache
Connected to Redis: PONG
Add FlowRouter FlowName=CalStuAvgScore12
===> Call Connector InitScore12Cache
Connected to Redis: PONG
Add FlowRouter FlowName=CalStuAvgScore3
->Call Func VerifyStu
->Call Func VerifyStu
->Call Func AvgStuScore12
->Call Func LoadScoreAvg12
->Call Func SaveScoreAvg12
->Call Func PrintStuAvgScore, in Flow[CalStuAvgScore12]
stuid: [101], avg score: [95]
stuid: [102], avg score: [90]
->Call Func AvgStuScore3
->Call Func PrintStuAvgScore, in Flow[CalStuAvgScore3]
stuid: [101], avg score: [90]
stuid: [102], avg score: [83.33333333333333]

In Flow[CalStuAvgScore3], we observe the final computed average scores for scores 1, 2, and 3.

---

Author: Aceld
GitHub: https://github.com/aceld

KisFlow Open Source Project Address: https://github.com/aceld/kis-flow

Document: https://github.com/aceld/kis-flow/wiki

---

Part1-OverView
Part2.1-Project Construction / Basic Modules
Part2.2-Project Construction / Basic Modules
Part3-Data Stream
Part4-Function Scheduling
Part5-Connector
Part6-Configuration Import and Export
Part7-KisFlow Action
Part8-Cache/Params Data Caching and Data Parameters
Part9-Multiple Copies of Flow
Part10-Prometheus Metrics Statistics
Part11-Adaptive Registration of FaaS Parameter Types Based on Reflection

---

Case1-Quick Start
Case2-Flow Parallel Operation
Case3-Application of KisFlow in Multi-Goroutines
Case4-KisFlow in Message Queue (MQ) Applications

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