% git revert 504c0d33
error: commit 504c0d33e29dc4488bd1b4eb95574cd1f211fbcc is a merge but no -m option was given.
fatal: revert failed

% git log --oneline
47b4348 commit-1

% git revert 47b4348

% git log --oneline
566fa3e Revert "commit-1"
47b4348 commit-1

% git log --oneline
504c0d33 Merge pull request #123 from xxxxxx

% git revert 504c0d33
error: commit 504c0d33e29dc4488bd1b4eb95574cd1f211fbcc is a merge but no -m option was given.
fatal: revert failed

% git revert -m 1 <merge commit id>

% git revert -m 2 <merge commit id>

% git revert -h

...
    --quit                end revert or cherry-pick sequence
    --continue            resume revert or cherry-pick sequence
    --abort               cancel revert or cherry-pick sequence
    --skip                skip current commit and continue
    --cleanup       how to strip spaces and #comments from message
    -n, --no-commit       don't automatically commit
    -e, --edit            edit the commit message
    -s, --signoff         add Signed-off-by:
    -m, --mainline 
                          select mainline parent
    --rerere-autoupdate   update the index with reused conflict resolution if possible

% git show 504c0d33
commit 504c0d33e29dc4488bd1b4eb95574cd1f211fbcc (HEAD -> main, origin/main)
Merge: e41ec146 7f0af4ef
Author: xxxxxxxxx
Date:   xxxxxxxxx

Build failed: The "Run fastlane" step failed with an unknown error. Refer to "Xcode Logs" below for additional, more detailed logs.

› Compiling @config-plugins/react-native-branch Pods/ExpoAdapterBranch » BranchAppDelegate.swift

❌  (node_modules/@config-plugins/react-native-branch/ios/ExpoAdapterBranch/BranchAppDelegate.swift:1:8)

> 1 | import ExpoModulesCore
    |        ^ compiling for iOS 12.0, but module 'ExpoModulesCore' has a minimum deployment target of iOS 13.0: /Users/expo/Library/Developer/Xcode/DerivedData/IT-hfhagyzjhtdmvbfuwgocyplvlpbf/Build/Intermediates.noindex/ArchiveIntermediates/IT/BuildProductsPath/Release-iphoneos/ExpoModulesCore/ExpoModulesCore.swiftmodule/arm64-apple-ios.swiftmodule
  2 | import RNBranch
  3 | 
  4 | public class BranchAppDelegate: ExpoAppDelegateSubscriber {

ActiveRecord::Type::Boolean.new.cast('true') # => true
ActiveRecord::Type::Boolean.new.cast('false') # => false

module ActiveModel
  module Type

    ...
    class Boolean < Value
      FALSE_VALUES = [
        false, 0,
        "0", :"0",
        "f", :f,
        "F", :F,
        "false", :false,
        "FALSE", :FALSE,
        "off", :off,
        "OFF", :OFF,
      ].to_set.freeze

      ...
      private
        def cast_value(value)
          if value == ""
            nil
          else
            !FALSE_VALUES.include?(value)
          end
        end
    end
  end
end

ActiveRecord::Type::Boolean.new.cast('0') # => false
ActiveRecord::Type::Boolean.new.cast(0) # => false
ActiveRecord::Type::Boolean.new.cast('false') # => false
ActiveRecord::Type::Boolean.new.cast("FALSE") # => false
ActiveRecord::Type::Boolean.new.cast("off") # => false
ActiveRecord::Type::Boolean.new.cast("OFF") # => false

ActiveRecord::Type::Boolean.new.cast('1') # => true
ActiveRecord::Type::Boolean.new.cast(1) # => true
ActiveRecord::Type::Boolean.new.cast('true') # => true
ActiveRecord::Type::Boolean.new.cast('TRUE') # => true
ActiveRecord::Type::Boolean.new.cast('on') # => true
ActiveRecord::Type::Boolean.new.cast('ON') # => true

ActiveRecord::Type::Boolean.new.cast('') # => nil
ActiveRecord::Type::Boolean.new.cast(nil) # => nil

class Utility
  def self.to_bool(value)
    ActiveRecord::Type::Boolean.new.cast(value)
  end
end

> Utility.to_bool('true')
true

class String
  def to_bool
    ActiveRecord::Type::Boolean.new.cast(self)
  end
end

> 'true'.to_bool
true

class Sample1
  def self.foo
    bar
  end

  private

    def bar
      puts 'bar'
    end
end

> Sample1.foo
Traceback (most recent call last):
1: from test.rb:13:in `<main>'
test.rb:3:in `foo': undefined local variable or method `bar' for Sample1:Class (NameError)

class Sample1
  def self.foo
    bar
  end

  private

    def self.bar
      puts 'bar'
    end
end

// エラーなく実行できる
> Sample1.foo
bar

// privateメソッドを呼べている
> Sample1.bar
bar

class Sample2
  class << self # クラスメソッドで定義
    def foo
      bar
    end

    private

      def bar # クラスメソッド内でprivateメソッドを定義する
        puts 'bar'
      end
  end
end

> Sample2.foo
bar

class Sample2
  def self.foo # クラスメソッドで定義
    bar
  end
  class << self

    private

      def bar # 特異クラス内でprivateメソッドを定義する
        puts 'bar'
      end
  end
end

> Sample2.foo
bar

create table parent (
  id bigint not null auto_increment,
  name varchar(255),
  primary key (id)
);

create table children (
  id bigint not null auto_increment,
  parent_id bigint not null,
  name varchar(255),
  primary key (id),
  foreign key (parent_id) references parent (id) on delete restrict
);

% brew install graphviz

% dot -Tpng development.dot > development.png

create table parent (
  id bigint not null auto_increment,
  name varchar(255),
  primary key (id)
);

create table children (
  id bigint not null auto_increment,
  parent_id bigint not null,  -- NOTE: not null制約
  name varchar(255),
  primary key (id),
  foreign key (parent_id) references parent (id) on delete restrict -- NOTE: restrict制約
);

insert into parent (name) values ('name');

-- NOTE: parentに紐づくchidrenデータ
insert into children (name, parent_id) values ('children1', 1); 
insert into children (name, parent_id) values ('children2', 1);

mysql> select * from parent;
+----+------+
| id | name |
+----+------+
|  1 | name |
+----+------+

mysql> select * from children;
+----+-----------+-----------+
| id | parent_id | name      |
+----+-----------+-----------+
|  1 |         1 | children1 |
|  2 |         1 | children2 |
+----+-----------+-----------+

mysql> delete from parent where id = 1;
ERROR 1451 (23000): Cannot delete or update a parent row: 
a foreign key constraint fails (`development`.`children`, CONSTRAINT `children_ibfk_1` FOREIGN KEY (`parent_id`) REFERENCES `parent` (`id`))

-- NOTE: 必要に応じてテーブルを削除してください。
drop table children;
drop table parent;

-- NOTE: テーブル作成
create table parent (
  id bigint not null auto_increment,
  name varchar(255),
  primary key (id)
);

create table children (
  id bigint not null auto_increment,
  parent_id bigint not null,　-- NOTE: not null制約
  name varchar(255),
  primary key (id),
  foreign key (parent_id) references parent (id) on delete cascade　-- NOTE: cascade制約
);

insert into parent (name) values ('name');

-- NOTE: parentに紐づくchidrenデータ
insert into children (name, parent_id) values ('children1', 1); 
insert into children (name, parent_id) values ('children2', 1);

mysql> delete from parent where id = 1;
Query OK, 1 row affected (0.02 sec)

mysql> select * from parent;
Empty set (0.00 sec)

mysql> select * from children;
Empty set (0.01 sec)

-- NOTE: 必要に応じてテーブルを削除してください。
drop table children;
drop table parent;

-- NOTE: テーブル作成
create table parent (
  id bigint not null auto_increment,
  name varchar(255),
  primary key (id)
);

create table children (
  id bigint not null auto_increment,
  parent_id bigint, -- NOTE: null許容
  name varchar(255),
  primary key (id),
  foreign key (parent_id) references parent (id) on delete set null -- NOTE: set null制約
);

insert into parent (name) values ('name');

-- NOTE: parentに紐づくchidrenデータ
insert into children (name, parent_id) values ('children1', 1); 
insert into children (name, parent_id) values ('children2', 1);

mysql> delete from parent where id = 1;
Query OK, 1 row affected (0.02 sec)

mysql> select * from parent;
Empty set (0.01 sec)

mysql> select * from children;
+----+-----------+-----------+
| id | parent_id | name      |
+----+-----------+-----------+
|  1 |      NULL | children1 |
|  2 |      NULL | children2 |
+----+-----------+-----------+
2 rows in set (0.00 sec)

import cycle not allowed

./app
├─ a/a.go
├─ b/b.go
├─ main.go
└─ go.mod

module app

go 1.19

package main

import (
  "app/a"
)

func main() {
  a.CallB()
}

package a

import (
  "fmt"
  "app/b"
)

func PrintA() {
  fmt.Println("A")
}

func CallB() {
  b.PrintB()
}

package b

import (
  "fmt"
  "app/a"
)

func PrintB() {
  fmt.Println("B")
}

func CallA() {
  a.PrintA()
}

% go run main.go
package command-line-arguments
        imports app/a
        imports app/b
        imports app/a: import cycle not allowed

./root_dir
├─ app
│   ├─ main.go
│   ├─ go.mod
│   └─ go.sum
├─ docker-compose.yml
└─ Dockerfile

FROM golang:1.19-alpine

RUN apk update && apk add git

# appディレクトリの作成
RUN mkdir /go/src/app
# ワーキングディレクトリの設定
WORKDIR /go/src/app

version: '3'
services:
  app:
    build: .
    tty: true
    volumes:
      - ./app:/go/src/app
    depends_on:
      - mysql
    ports:
      - 8000:8000

  mailhog:
    image: mailhog/mailhog:latest
    ports:
      - "8025:8025" # MailhogのWebとAPI用のポート
      - "1025:1025" # SMTPポート

package main

import (
  "fmt"
  "net/smtp"
  "os"
  "strings"
)

var (
  hostname = "mailhog" // docker-composeで指定したサービス名
  port     = 1025 // mailhogのSMPTポート
  username = "user@example.com"
  password = "password"
  from     = "from@example.net"
  subject  = "hello"
  body     = "Hello World!"
  receiver = []string{"receiver@example.com"}
)

func main() {
  SendEmail()
}

func SendEmail() {
  smtpServer := fmt.Sprintf("%s:%d", hostname, port)
  auth := smtp.CRAMMD5Auth(username, password)
  msg := []byte(fmt.Sprintf("To: %s\nSubject: %s\n\n%s", strings.Join(receiver, ","), subject, body))

  if err := smtp.SendMail(smtpServer, auth, from, receiver, msg); err != nil {
    fmt.Fprintln(os.Stderr, err)
  }
}

% dc exec app sh
# go run main.go

$ brew install protobuf
$ go get -u google.golang.org/grpc
$ go get -u google.golang.org/grpc/cmd/protoc-gen-go-grpc

$ cd study_grpc # 作業ディレクトリ
$ go mod init mygrpc

./study_grpc # 作業ルートディレクトリ
├─ api
│   └─ hello.proto # protoファイル
├─ cmd
│   ├─ server
│   │ └─ main.go
│   └─ client
│        └─ main.go
├─ pkg
│   └─ grpc # ここにコードを自動生成させる
│         ├─ hello.pb.go
│         └─ hello_grpc.pb.go
├─ go.mod
└─ go.sum

// protoのバージョンの宣言
syntax= "proto3";

// protoファイルから自動生成させるGoのコードの置き先
// (詳細は4章にて)
option go_package = "pkg/grpc";

// packageの宣言
package myapp;

// サービスの定義
service GreetingService {
   // サービスが持つメソッドの定義
  rpc Hello (HelloRequest) returns (HelloResponse);
}

// 型の定義
message HelloRequest {
   stringname = 1;
}

message HelloResponse {
   stringmessage = 1;
}

$  cd api
$ protoc --go_out=../pkg/grpc --go_opt=paths=source_relative \
         --go-grpc_out=../pkg/grpc --go-grpc_opt=paths=source_relative \
         hello.proto

$ protoc --go_out=./ --go-grpc_out=./ api/hello.proto

package main

import (
  "fmt"
  "net"
  "log"
  "os"
  "context"
  "os/signal"
  "google.golang.org/grpc"
  "google.golang.org/grpc/reflection"
  hellopb "mygrpc/pkg/grpc"
)

func NewMyServer() *myServer {
  return &myServer{}
}

func main() {
  // 1. 8080番portのLisnterを作成
  port := 8080
  listener, err := net.Listen("tcp", fmt.Sprintf(":%d", port))
  if err != nil {
    panic(err)
  }

  // 2. gRPCサーバーを作成
  s := grpc.NewServer()

  // 3. gRPCサーバーにGreetingServiceを登録
  hellopb.RegisterGreetingServiceServer(s, NewMyServer())

  // 4. サーバーリフレクションの設定
  reflection.Register(s)

  // 5. 作成したgRPCサーバーを、8080番ポートで稼働させる
  go func() {
    log.Printf("start gRPC server port: %v", port)
    s.Serve(listener)
  }()

  // 6.Ctrl+Cが入力されたらGraceful shutdownされるようにする
  quit := make(chan os.Signal, 1)
  signal.Notify(quit, os.Interrupt)
  <-quit
  log.Println("stopping gRPC server...")
  s.GracefulStop()
}

type myServer struct {
  hellopb.UnimplementedGreetingServiceServer
}

func (s *myServer) Hello(ctx context.Context, req *hellopb.HelloRequest) (*hellopb.HelloResponse, error) {
  // リクエストからnameフィールドを取り出して
  // "Hello, [名前]!"というレスポンスを返す
  return &hellopb.HelloResponse{
    Message: fmt.Sprintf("Hello, %s!", req.GetName()),
  }, nil
}

$ brew  install grpcurl

$ go cmd/server/run main.go
2023/02/13 10:01:38 start gRPC server port: 8080

package main

import (
  "bufio"
  "fmt"
  "os"
  "log"
  "context"
  "google.golang.org/grpc"
  "google.golang.org/grpc/credentials/insecure"
  hellopb "mygrpc/pkg/grpc"
)

var (
  scanner *bufio.Scanner
  client  hellopb.GreetingServiceClient
)

func main() {
  fmt.Println("start gRPC Client.")

  // 1. 標準入力から文字列を受け取るスキャナを用意
  scanner = bufio.NewScanner(os.Stdin)

  // 2. gRPCサーバーとのコネクションを確立
  address := "localhost:8080"
  conn, err := grpc.Dial(
    address,

    grpc.WithTransportCredentials(insecure.NewCredentials()),
    grpc.WithBlock(),
  )
  if err != nil {
    log.Fatal("Connection failed.")
    return
  }
  defer conn.Close()

  // 3. gRPCクライアントを生成
  client = hellopb.NewGreetingServiceClient(conn)

  for {
    fmt.Println("1: send Request")
    fmt.Println("2: exit")
    fmt.Print("please enter >")

    scanner.Scan()
    in := scanner.Text()

    switch in {
    case "1":
      Hello()

    case "2":
      fmt.Println("bye.")
      goto M
    }
  }
M:
}

func Hello() {
  fmt.Println("Please enter your name.")
  scanner.Scan()
  name := scanner.Text()

  req := &hellopb.HelloRequest{
    Name: name,
  }
  res, err := client.Hello(context.Background(), req)
  if err != nil {
    fmt.Println(err)
  } else {
    fmt.Println(res.GetMessage())
  }
}

FROM golang:1.19.5-buster

ENV PROTOBUF_VERSION3.17.3

RUN apt-getupdate \
    && apt-getinstall -y protobuf-compiler unzip --no-install-recommends \
    && apt-getclean \
    && rm-rf /var/lib/apt/lists/*

WORKDIR /grpc
COPY. /grpc

## build時のみ使いたいので、runで実行。
RUN go install google.golang.org/protobuf/cmd/protoc-gen-go@latest
RUN go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@latest
RUN go get google.golang.org/grpc/internal/channelz@v1.53.0

version:'3'

services:
  grpc:
    build: .
    volumes:
      - .:/grpc
    ports:
      - "8080:8080"
   tty: true

$ docker-compose up

$ docker-compose exec grpc bash
> go run cmd/server/main.go
2023/02/13 10:01:38 start gRPC server port: 8080

$ docker-compose exec grpc bash
> go run cmd/client/main.go
1: Hello
2:exit
please enter>1

Please enter your name.
shungo
Hello, shungo!

1: Hello
2:exit
please enter>2

bye.

<Text numberOfLines={1} ellipsizeMode="tail">
  abcdefghijklmnopqrstuvwxyz
</Text>

display: -webkit-box;
-webkit-box-orient: vertical;
-webkit-line-clamp: 3;
overflow: hidden;