Using special SSH key for Git

In ~/.ssh/config:

host github.com
    HostName github.com
    IdentityFile ~/.ssh/id_rsa_github
    User git

don’t forget chmod 600 ~/.ssh/config

Or, use GIT_SSH_COMMAND environment variable:

export GIT_SSH_COMMAND="ssh -i ~/.ssh/id_rsa_example -F /dev/null"

Regex Unicode Scripts

\p{Han} 匹配中文、日语文字，支持简繁体。
\p{Common} 匹配符号
\p{Latin} 匹配拉丁语系
需要 grep perl 支持，即 grep -P "\p{Han}"，或者 rg/ag.

echo '中文/繁體/片仮名／かたかな／カタカナ/katakana' | rg "\p{Han}"   > 中文 繁體 片仮名
echo '中文@mail.com' | rg "\p{Common}"                                > @ .
echo '中文@mail.com' | rg "\p{Latin}"                                 > mail com

Unicode Scripts for more.

Octotree for Safari

From Safari 13, you can only install extension from Mac App Store.

brew install node@10
export PATH="/usr/local/opt/node@10/bin:$PATH"
# make sure node and npm is v10, cause octotree used gulp 3, which is not working with node 12.

git clone https://github.com/ovity/octotree.git ~/src/octotree
cd ~/src/octotree
git checkout master

npm i
npm install [email protected]
npm run dist
# extension locate in ~/src/octotree/tmp/safari/octotree.safariextension/

cd ~/Library/Safari/Extensions
mv ~/src/octotree/tmp/safari/octotree.safariextension .

Enable Developer menu in Safari
Developer - Show Extension Builder
Add octotree.safariextension and Run

MySQL Prefix Index

CREATE TABLE `t1` (
  `bundle` varchar(300) DEFAULT '' COMMENT 'pkg name',
  `domain` varchar(200) DEFAULT '',
  UNIQUE KEY `idx_bundle_domain` (`bundle`(100),`domain`(100))
) ENGINE=InnoDB AUTO_INCREMENT=12 DEFAULT CHARSET=utf8mb4;

关键部分 bundle(100) 来解决组合索引可能会出现的 Specified key was too long; max key length is 767 bytes 错误。

Deployment with git

#!/bin/sh

set -uex

PATH=$PATH:$HOME/bin
export PATH

DIR=/home/serv/project
cd ${DIR}

REV1=$(git rev-parse --verify HEAD)
git pull origin master
REV2=$(git rev-parse --verify HEAD)
test ${REV1} = ${REV2} && echo "Already updated" && exit

make
test $? -ne 0 && echo "make error" && exit

kill -HUP $(cat logs/run.pid)

主要是通过 git rev-parse --verify HEAD 来获取当前 rev hash，前后对比是否一致，以此来决定是否继续。

logrotate

logrotate - rotates, compresses, and mails system logs

# 0 0 * * * /usr/sbin/logrotate --state=/home/serv/logrotate.state /home/serv/logrotate.log.conf
/home/serv/logs/dev.log
/home/serv/logs/access.log {
    rotate 10
    daily
    compress
    create
    copytruncate
    missingok
    dateext
    dateformat -%Y-%m-%d
    dateyesterday

    sharedscripts
    postrotate
        kill -USR1 `cat /var/run/nginx.pid`
    endscript
}

要么保存到 /etc 配置，由系统调度。也可以自己通过 crontab 调度控制，这种情况要注意加 --state 来保存状态
像 nginx 可以通过 kill -USR1 来重新打开日志文件，如果服务不支持可以用 copytruncate，先拷贝再清空

Druid Query in JSON

Druid 可以在 Superset SQL 查询，除此之外可以通过 HTTP+JSON 查询:

curl -X POST '<host:<port>/druid/v2/?pretty' -H 'Content-Type:application/json' -H 'Accept:application/json' -d @query.json

{
  "queryType": "timeseries",
  "dataSource": "cpm_log",
  "granularity": "hour",
  "aggregations": [
    {
      "type": "longSum",
      "name": "requests",
      "fieldName": "req_count_raw"
    },
    {
      "type": "longSum",
      "name": "impressions",
      "fieldName": "win_count"
    },
    {
      "type": "floatSum",
      "name": "revenues",
      "fieldName": "win_price"
    }
  ],
  "postAggregations": [
    {
      "type":"arithmetic",
      "name": "ecpm",
      "fn": "/",
      "fields": [
        {
          "type": "fieldAccess",
          "name": "postAgg_rev",
          "fieldName": "revenues"
        },
        {
          "type": "fieldAccess",
          "name": "postAgg_imps",
          "fieldName": "impressions"
        }
      ]
    }
  ],
  "filter": {
    "type": "and",
    "fields": [
      {
        "type": "selector",
        "dimension": "device_os",
        "value": "android"
      },
      {
        "type": "in",
        "dimension": "req_ad_type",
        "values": ["banner"]
      }
    ]
  },
  "context": {
    "grandTotal": true
  },
  "intervals": [
    "2019-04-09T00:00:00+08:00/2019-04-09T23:00:00+08:00"
  ]
}

queryType 有 timeseries, topN, groupBy, search, timeBoundary 等
尽量少用 groupBy 查询，效率不高
topN 查询是通过 metric 来排序
context 可以指定 queryId，这样可以通过 DELETE /druid/v2/{queryId} 取消查询
去重: {"type": "cardinality", "name": "distinct_pid", "fields": ["ad_pid"]}

RTFM, godruid

To Appwill

昨天梦到了 AW。

不是现在的 AW，是几年前的，很多人都还在，一起讨论某个产品。

那时的 AW 很小，但有凝聚力，有战斗力，很 nice。后来有好几个人都跟我说过，那时的 AW 是大家最棒的经历。

什么时候是个转折呢？大概就是 15年吧，Z 移民澳洲后产品上一直没有太好的 Lead，之后日活下降收入走低，产品开始往下走。16年后 L 对现有产品兴趣不大，改组内部项目制，效果也不好。

再后来，17年初 L 组建新公司，Z&Z 言明不可从原公司挖人，结果就是一起拼搏走过来的人，跟着已经死去的旧产品沉没，之后相继离职，包括我。

我个人对 AW 的感情很深，但说实话，最后创始人分家+限制挖人，让我心里很不舒服，本身我们还可以一起用彼此都信任的方式做事，结果却似有欺骗，维护着注定要死去的产品，费劲心力，却无成长。

R.I.P.

Nginx proxy_next_upstream non_idempotent

在 Nginx 做反向代理的时候，我们一般会配置 proxy_next_upstream，如果某个 upstream 超时或出错，自动切换到下一个 upstram。

upstream backend{
  server 192.168.0.1;
  server 192.168.0.2;
}
location /example/ {
   proxy_pass http://backend;

   proxy_next_upstream error timeout http_500 non_idempotent;
}

这里有一个地方需要注意，non_idempotent，Nginx 默认对 non-idempotent 请求，比如 POST/LOCK/PATCH，是不进行重试。常见的情况就是 POST 请求出错后不会重试，需要加上该设置。

normally, requests with a non-idempotent method (POST, LOCK, PATCH) are not passed to the next server if a request has been sent to an upstream server (1.9.13); enabling this option explicitly allows retrying such requests;

Homebrew Speedup

通过修改 Homebrew git repo 来加速：

cd "$(brew --repo)"
git remote set-url origin https://mirrors.tuna.tsinghua.edu.cn/git/homebrew/brew.git
// 中科大 git remote set-url origin https://mirrors.ustc.edu.cn/brew.git

cd "$(brew --repo)/Library/Taps/homebrew/homebrew-core"
git remote set-url origin https://mirrors.tuna.tsinghua.edu.cn/git/homebrew/homebrew-core.git
// 中科大 git remote set-url origin https://mirrors.ustc.edu.cn/homebrew-core.git

// homebrew-cask
cd "$(brew --repo)/Library/Taps/homebrew/homebrew-cask"
git remote set-url origin https://mirrors.ustc.edu.cn/homebrew-cask.git

// homebrew-bottles
export HOMEBREW_BOTTLE_DOMAIN=https://mirrors.tuna.tsinghua.edu.cn/homebrew-bottles
// export HOMEBREW_BOTTLE_DOMAIN=https://mirrors.ustc.edu.cn/homebrew-bottles
// export HOMEBREW_BOTTLE_DOMAIN=http://7xkcej.dl1.z0.glb.clouddn.com

重置为官方源：

cd "$(brew --repo)"
git remote set-url origin https://github.com/Homebrew/brew.git

cd "$(brew --repo)/Library/Taps/homebrew/homebrew-core"
git remote set-url origin https://github.com/Homebrew/homebrew-core

cd "$(brew --repo)/Library/Taps/homebrew/homebrew-cask"
git remote set-url origin https://github.com/Homebrew/homebrew-cask

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