DEV Community: FRedwuSong

rails database 改成 mysql 所遇到的問題

FRedwuSong — Tue, 12 Dec 2023 09:01:44 +0000

環境：

ruby 2.5.9
Rails 6.1.7.6
spring 3.1.1
sqlite3 1.4.4

rails 專案預設是使用 sqlite ; 因為要練習的關係所以想換成 MySQL

rails6 有新增一個指令可以直接切換 rails 所使用的資料庫種類
https://github.com/rails/rails/issues/34710

rails db:system:change --to=postgresql|mysql|sqlite

但是我卻遇到問題

rails db:system:change --to=mysql
Running via Spring preloader in process 61295
invalid option: --to=mysql

發現是 spring 版本的問題，需要改 spring 的版本
https://github.com/rails/spring/issues/678
改用 rubygems 預設的版本 1.7.2
https://rubygems.org/gems/spring/versions/1.7.2?locale=zh-TW
編輯 gemfile

gem 'spring', '~> 1.7', '>= 1.7.2'
gem 'mysql2', '~> 0.5'
# 這邊還要再把 sqlite3 1.4.4 換成 mysql2 0.5.5

之後再 bundle install。
下 rails db:system:change --to=mysql

    conflict  config/database.yml
Overwrite /private/tmp/rails_617/mysqlpractice/config/database.yml? (enter "h" for help) [Ynaqdhm] Y
       force  config/database.yml
        gsub  Gemfile
        gsub  Gemfile

恭喜！！！！～～～
已經成功把 sqlite 換成 MySQL 啦～～～

解決 gem install mysql2 時遇到 'zstd' not found 錯誤的問題

FRedwuSong — Tue, 12 Dec 2023 08:19:17 +0000

單純地使用

gem install mysql2

安裝會有library 'zstd' not found的 error

linking shared-object mysql2/mysql2.bundle
ld: library 'zstd' not found
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [mysql2.bundle] Error 1

make failed, exit code 2

Gem files will remain installed in /Users/sung/.asdf/installs/ruby/2.5.9/lib/ruby/gems/2.5.0/gems/mysql2-0.5.5 for inspection.
Results logged to /Users/sung/.asdf/installs/ruby/2.5.9/lib/ruby/gems/2.5.0/extensions/-darwin-23/2.5.0/mysql2-0.5.5/gem_make.out

stackoverflow 這篇提到

Jun 4 '21 Comments: 1 Answers: 4

while running bundle install

An error occurred while installing mysql2 (0.5.3), and Bundler cannot continue
Make sure that `gem install mysql2 -v '0.5.3' --source 'https://rubygems.org/'` succeeds before bundling.

Rails app 6.1.3

Bundler version 2.2.19

macOS Big Sur 11.4

Apple M1

in the Gemfile

ruby '2.6.6'
gem 'rails', '~> 6.1.3', '>=

…

Open Full Question

在安裝要特地指名 openssl 和 zstd。

指令如下：

gem install mysql2 -v '0.5.5' -- --with-opt-dir=$(brew --prefix openssl) --with-ldflags=-L/opt/homebrew/opt/zstd/lib

這樣就成功啦～～～

gem install mysql2 -v '0.5.5' -- --with-opt-dir=$(brew --prefix openssl) --with-ldflags=-L/opt/homebrew/opt/zstd/lib
Building native extensions with: '--with-opt-dir=/opt/homebrew/opt/openssl@3 --with-ldflags=-L/opt/homebrew/opt/zstd/lib'
This could take a while...
Successfully installed mysql2-0.5.5
Parsing documentation for mysql2-0.5.5
Installing ri documentation for mysql2-0.5.5
Done installing documentation for mysql2 after 0 seconds
1 gem installed

gem install rails 幫我們做了什麼事勒？

FRedwuSong — Mon, 11 Dec 2023 20:11:15 +0000

會有這個想法，是因為心血來潮用比較舊的 ruby 版本（ 2.5.9 ）來安裝 rails 6（ 6.1.7 ），結果噴錯!!!!!

ERROR:  Error installing rails:
    The last version of nokogiri (>= 1.8.5) to support your Ruby & RubyGems was 1.12.5. Try installing it with `gem install nokogiri -v 1.12.5` and then running the current command again
    nokogiri requires Ruby version >= 2.7.0. The current ruby version is 2.5.0.

完全摸不著頭緒啊，rails 6 查資料應該有支持 ruby 2.5
https://www.fastruby.io/blog/ruby/rails/versions/compatibility-table.html
前輩指路https://qiita.com/murata0705/items/dfa2fed6c773f925a975

當您做

gem install rails --version=6.1.7

他在安裝完 activesupport 後要裝 actionpack 前，想幫您裝 rails-html-sanitizer 預設是裝 1.6 版 (明明 >= 1.2.0 就行)，但裝 rails-html-sanitizer 前必須先裝 nokogiri 預設是 nokogiri 1.15.5 ~> 1.14 但是我 ruby 的版本是 2.5.9 沒辦法裝。
所以才會有圖一的問題。
怎麼辦哪：

1. gem install nokogiri -v 1.12.5；不裝的話會預設幫您裝 -v 1.15.5。
2. gem install rails-html-sanitizer -v 1.5.0
3. gem install rails -v 6.1.7

處理完後會遇到目前此套件的版本只支持 ruby 2.6 ERRORs；

ERROR:  Error installing rails:
    The last version of bundler (>= 1.15.0) to support your Ruby & RubyGems was 2.3.27. Try installing it with `gem install bundler -v 2.3.27` and then running the current command again
    bundler requires Ruby version >= 2.6.0. The current ruby version is 2.5.0.

必須手動安裝他建議的版本，總共裝了這些。

gem install bundler -v 2.3.27
gem install thor -v 1.2.2
gem install mini_mime -v 1.1.2
gem install timeout -v 0.4.0
gem install net-protocol -v 0.1.2
gem install net-imap -v 0.2.2

之後終於成功裝好了 rails 6.1.7。

至於為何有那麼多 gem 要手動裝呢？一般不是直接

gem install rails

就好了嗎？
因為 rails 是用很多 gem 包起來的，以 rails 6.1 為例
https://github.com/rails/rails/blob/6-1-stable/rails.gemspec

  s.add_dependency "activesupport", version
  s.add_dependency "actionpack",    version
  s.add_dependency "actionview",    version
  s.add_dependency "activemodel",   version
  s.add_dependency "activerecord",  version
  s.add_dependency "actionmailer",  version
  s.add_dependency "activejob",     version
  s.add_dependency "actioncable",   version
  s.add_dependency "activestorage", version
  s.add_dependency "actionmailbox", version
  s.add_dependency "actiontext",    version
  s.add_dependency "railties",      version

被包起來的 gem 也包了其他 gem 以 net-protocol 來舉例 :

gem install rails -v 6.1.7
Fetching: net-protocol-0.2.2.gem (100%)
ERROR:  Error installing rails:
    The last version of net-protocol (>= 0) to support your Ruby & RubyGems was 0.1.2. Try installing it with `gem install net-protocol -v 0.1.2` and then running the current command again
    net-protocol requires Ruby version >= 2.6.0. The current ruby version is 2.5.0.

上面的大意是我要 Fetching: net-protocol-0.2.2.gem 裝不了; 您 ruby 版本是 2.5.0 去裝 net-protocol -v 0.1.2

gem install net-protocol -v 0.1.2
Fetching: io-wait-0.3.0.gem (100%)
Building native extensions. This could take a while...
Successfully installed io-wait-0.3.0
Fetching: net-protocol-0.1.2.gem (100%)
Successfully installed net-protocol-0.1.2
Parsing documentation for io-wait-0.3.0
Installing ri documentation for io-wait-0.3.0
Parsing documentation for net-protocol-0.1.2
Installing ri documentation for net-protocol-0.1.2
Done installing documentation for io-wait, net-protocol after 0 seconds
2 gems installed

為什麼 net-protocol -v 0.1.2 可以呢？
主要是因為 net-protocol -v 0.1.2 的版本需求是 >= 2.3.0
而且，io-wait >= 0 和 timeout >= 0 都沒有特別指定的版本，再加上 mail 對於 net-imap >= 0, net-pop >= 0, net-smtp >=0 的版本也沒有要求，而上開 gem 對 net-protocol >= 0 也沒有要求，所以就慢慢手動裝他要求的版本大概就不會有什麼問題。
~~為什麼都預設去抓只支持 2.6 以上的版本~~
原因我猜是因爲預設去抓最新版，但最新版無法使用 ruby 2.5 安裝的最新的版本。(／‵口′)／~╧╧ )
thanks god !!!!!!! 不免俗地說 happy ~~coding~~ installing~~
編按：
https://github.com/rails/rails-html-sanitizer/releases/tag/v1.6.0