Go で JSON をマージする(Jeffail/gabs 編)

• 開発環境起動
• 環境構築
• JSON ファイル作成
• プログラム実装
• 実行
• 参考資料

mikoto2000/devcontainer.vim: コンテナ上で Vim を使った開発をするためのツール。 VSCode Dev Container の Vim 版を目指しています。 の中で、 JSON をマージしたいという要求が出てきたので Jeffail/gabs: For parsing, creating and editing unknown or dynamic JSON in Go を試す。

開発環境起動

docker run -it --rm -v "$(pwd):/work" --workdir /work -v "$HOME/.vim:/root/.vim" golang:1.22.1-bookworm

環境構築

go mod init github.com/mikoto2000/golang/json/gabs/firststep
go get github.com/Jeffail/gabs/v2

JSON ファイル作成

json/base.json:

{
  "name":"Go",
  "image":"mcr.microsoft.com/devcontainers/go:1-1.22-bookworm",
  "mounts": [
    {
      "type": "bind",
      "source": "${localEnv:HOME}/.gitconfig",
      "target": "/home/vscode/.gitconfig"
    }
  ],
  "features":{},
  "remoteUser":"vscode"
}

json/additional.json:

{
  "mounts": [
    {
      "type": "bind",
      "source": "${localEnv:HOME}/.vim",
      "target": "/home/vscode/.vim"
    }
  ]
}

プログラム実装

package main

import (
        "fmt"

        "github.com/Jeffail/gabs/v2"
)

const baseJsonFilePath = "json/base.json"
const additionalJsonFilePath = "json/additional.json"

func main() {
        parsedBaseJson, err := gabs.ParseJSONFile(baseJsonFilePath)
        if err != nil {
                panic(err)
        }
        fmt.Printf("=== %s ===\n", baseJsonFilePath)
        fmt.Println(parsedBaseJson.StringIndent("", "  "))
        fmt.Println()

        parsedAdditionalJson, err := gabs.ParseJSONFile(additionalJsonFilePath)
        if err != nil {
                panic(err)
        }
        fmt.Printf("=== %s ===\n", additionalJsonFilePath)
        fmt.Println(parsedAdditionalJson.StringIndent("", "  "))
        fmt.Println()

        parsedBaseJson.Merge(parsedAdditionalJson)
        fmt.Printf("=== Merged JSON %s and %s ===\n", baseJsonFilePath, additionalJsonFilePath)
        fmt.Println(parsedBaseJson.StringIndent("", "  "))
        fmt.Println()
}

実行

root@696abd662a3a:/work# go run main.go
=== json/base.json ===
{
  "features": {},
  "image": "mcr.microsoft.com/devcontainers/go:1-1.22-bookworm",
  "mounts": [
    {
      "source": "${localEnv:HOME}/.gitconfig",
      "target": "/home/vscode/.gitconfig",
      "type": "bind"
    }
  ],
  "name": "Go",
  "remoteUser": "vscode"
}

=== json/additional.json ===
{
  "mounts": [
    {
      "source": "${localEnv:HOME}/.vim",
      "target": "/home/vscode/.vim",
      "type": "bind"
    }
  ]
}

=== Merged JSON json/base.json and json/additional.json ===
{
  "features": {},
  "image": "mcr.microsoft.com/devcontainers/go:1-1.22-bookworm",
  "mounts": [
    {
      "source": "${localEnv:HOME}/.gitconfig",
      "target": "/home/vscode/.gitconfig",
      "type": "bind"
    },
    {
      "source": "${localEnv:HOME}/.vim",
      "target": "/home/vscode/.vim",
      "type": "bind"
    }
  ],
  "name": "Go",
  "remoteUser": "vscode"
}

参考資料

• Jeffail/gabs: For parsing, creating and editing unknown or dynamic JSON in Go