介紹
jq is like sed for JSON data - you can use it to slice and filter and map and transform structured data with the same ease that sed, awk, grep and friends let you play with text.
jq 可以對(duì) JSON 數(shù)據(jù)進(jìn)行切片、過(guò)濾、映射和轉(zhuǎn)換，和sed, awk, grep 命令一樣簡(jiǎn)單好用。
jq is written in portable C, and it has zero runtime dependencies. You can download a single binary, scp it to a far away machine of the same type, and expect it to work.
jq 是用 C語(yǔ)言編寫的，沒(méi)有運(yùn)行時(shí)依賴。獨(dú)立二進(jìn)制文件，可以使用 scp 復(fù)制到其他服務(wù)器直接運(yùn)行。
安裝
linux
# 下載 https://stedolan.github.io/jq/download/
$ wget https://github.com/stedolan/jq/releases/download/jq-1.6/jq-linux64 -O /usr/local/bin/jq
# 執(zhí)行權(quán)限
$ chmod +x /usr/local/bin/jq
OS X
$ brew install jq
使用
以 njmon 的 json 輸出來(lái)演示 jq 的常用方式，高級(jí)用法見(jiàn)官方手冊(cè)。
jq "."
以 json格式化輸出。
$ njmon -s 1 -c 1 | jq '.'
{
"timestamp": {
"datetime": "2020-03-14T19:59:22",
"UTC": "2020-03-14T11:59:22",
"snapshot_seconds": 1,
"snapshot_maxloops": 1,
"snapshot_loop": 0
},
..... 省略其他輸出
}
指定 key 查詢
$ njmon -s 1 -c 1 | jq '.timestamp'
{
"datetime": "2020-03-14T20:14:00",
"UTC": "2020-03-14T12:14:00",
"snapshot_seconds": 1,
"snapshot_maxloops": 1,
"snapshot_loop": 0
}
$ njmon -s 1 -c 1 | jq '.timestamp.datetime'
"2020-03-14T20:14:43"
--raw-output/-r
標(biāo)準(zhǔn)輸出，即不格式化為帶引號(hào)的json 字符串
$ njmon -s 1 -c 1 | jq '.timestamp.datetime'
"2020-03-14T20:14:43"
$ njmon -s 1 -c 1 | jq -r '.timestamp.datetime'
2020-03-14T20:14:43
@csv：格式化輸出
還有其他格式方式： @html,@sh,@base64,@base64d等。
$ njmon -s 1 -c 1 | jq -r 'keys' | jq -r '@csv'
"cpu_total","cpuinfo","cpus","disks","filesystems","identity","lscpu","networks","os_release","proc_meminfo","proc_version","proc_vmstat","stat_counters","timestamp","uptime"
數(shù)組
$ njmon -s 1 -c 1 | jq '.cpus'
{
"cpu0": {
"user": 0.999,
"nice": 0,
"sys": 0.999,
"idle": 99.87,
"iowait": 0,
"hardirq": 0,
"softirq": 0,
"steal": 0,
"guest": 0,
"guestnice": 0
},
"cpu1": {
"user": 2.996,
"nice": 0,
"sys": 0.999,
"idle": 97.873,
"iowait": 0,
"hardirq": 0,
"softirq": 0,
"steal": 0,
"guest": 0,
"guestnice": 0
}
}
$ njmon -s 1 -c 1 | jq '.cpus[]'
{
"user": 0.999,
"nice": 0,
"sys": 0.999,
"idle": 99.92,
"iowait": 0,
"hardirq": 0,
"softirq": 0,
"steal": 0,
"guest": 0,
"guestnice": 0
}
{
"user": 2.998,
"nice": 0,
"sys": 0.999,
"idle": 97.922,
"iowait": 0,
"hardirq": 0,
"softirq": 0,
"steal": 0,
"guest": 0,
"guestnice": 0
}
函數(shù)
keys：獲取JSON中的key信息
$ njmon -s 1 -c 1 | jq 'keys'
[
"cpu_total",
"cpuinfo",
"cpus",
"disks",
"filesystems",
"identity",
"lscpu",
"networks",
"os_release",
"proc_meminfo",
"proc_version",
"proc_vmstat",
"stat_counters",
"timestamp",
"uptime"
]
select(boolean_expression)：搜索指定條件內(nèi)容
$ njmon -s 1 -c 1 | jq '.filesystems[] | select(.fs_dir == "/home")'
{
"fs_dir": "/home",
"fs_type": "ext4",
"fs_opts": "rw,seclabel,relatime,data=ordered",
"fs_freqs": 0,
"fs_passno": 0,
"fs_bsize": 4096,
"fs_size_mb": 11502,
"fs_free_mb": 11448,
"fs_used_mb": 54,
"fs_full_percent": 0.463,
"fs_avail": 10842,
"fs_files": 757392,
"fs_files_free": 757110,
"fs_namelength": 255
}
has(key)：判斷是否存在某個(gè)key
$ njmon -s 1 -c 1 | jq 'has("cpus")'
true
$ njmon -s 1 -c 1 | jq 'has("cpus2")'
false
length：查看輸出長(zhǎng)度或個(gè)數(shù)
# 5 個(gè)字段
$ njmon -s 1 -c 1 | jq '.timestamp | length'
5
# 長(zhǎng)度 19
$ njmon -s 1 -c 1 | jq '.timestamp.datetime | length'
19
實(shí)際場(chǎng)景
nacos 工具腳本
在做自動(dòng)部署腳本時(shí)，需要寫個(gè) Nacos 工具腳本，實(shí)現(xiàn)操作 Nacos 實(shí)例狀態(tài)查看、下線、上線等。針對(duì) Nacos 的 json 結(jié)構(gòu)數(shù)據(jù)，使用 jq 來(lái)進(jìn)行處理。腳本如下：
nacosUtils.sh
#!/bin/bash
# Nacos工具腳本
# 使用方法
usage() {
echo "Usage: sh $0 {instance|instances|offline|online} URL NAMESPACE_ID SERVICE_NAME IP PORT [FORCE]"
echo "n"
echo "t {instance|instances|offline|online} 方法名稱"
echo "tt -instance：查詢某個(gè)健康實(shí)例狀態(tài)，true表示在線狀態(tài)，false表示下線狀態(tài), 返回空表示實(shí)例不存在"
echo "tt -instances：查詢健康實(shí)例總數(shù)"
echo "t SERVICE_NAME 系統(tǒng)名稱"
echo "t IP 實(shí)例IP"
echo "t PORT 實(shí)例啟動(dòng)端口號(hào)"
echo "t FORCE 方法為offline時(shí)，true表示強(qiáng)制下線，非true表示校驗(yàn)是否多于2個(gè)健康實(shí)例"
echo "n"
echo "示例："
echo "t 啟動(dòng)：sh $0 instance http://127.0.0.1/nacos ****** serviceName x.x.x.x 8090"
}
# 判斷參數(shù)
if [ $# -lt 4 ];
then
usage
exit 1
fi
# nacos url
URL=$2
# nacos 命名空間
NAMESPACE_ID=$3
# 系統(tǒng)名稱
SERVICE_NAME=$4
# 實(shí)例 IP地址
IP=$5
# 端口
PORT=$6
# 強(qiáng)制下線標(biāo)識(shí)
FORCE=$7
# 查看實(shí)例url
instanceListUrl="$URL/v1/ns/catalog/instances?serviceName=$SERVICE_NAME&clusterName=DEFAULT&pageSize=10&pageNo=1&namespaceId=$NAMESPACE_ID"
# 更新實(shí)例
instanceUrl="$URL/v1/ns/instance?serviceName=$SERVICE_NAME&ip=$IP&port=$PORT&namespaceId=$NAMESPACE_ID"
# 查詢健康且上線的實(shí)例個(gè)數(shù)
function instances() {
echo `curl -X GET -s $instanceListUrl | jq -r ".list[] | select(.healthy == true) | select(.enabled == true) | .ip" | wc -l`
}
# 查詢健康實(shí)例狀態(tài) 在線：true；下線：false, 沒(méi)有查詢到: 空
function instance() {
echo `curl -X GET -s $instanceListUrl | jq -r ".list[] | select(.ip == "$IP") | select(.port == $PORT) | select(.healthy == true) | .enabled"`
}
# 下線 健康實(shí)例總數(shù)為1時(shí)，不可下線唯一的服務(wù)
function offline() {
if [ "X$FORCE" != "Xtrue" ];then
counts=`instances`
if [ $counts -lt 2 ];then
curl -X GET -s $instanceListUrl | jq .
echo "$SERVICE_NAME 實(shí)例總數(shù)小于2個(gè)，不可下線唯一的服務(wù)！！！"
exit 1
fi
fi
result=`curl -X PUT -s "$instanceUrl&enabled=false"`
echo $result
}
# 上線
function online() {
enabledFlag=`instance`
if [ "X$enabledFlag" == "Xtrue" ]; then
curl -X GET -s $instanceListUrl | jq .
echo "$SERVICE_NAME 實(shí)例為上線狀態(tài)，無(wú)需執(zhí)行上線！！！"
else
result=`curl -X PUT -s "$instanceUrl&enabled=true"`
fi
echo $result
}
case "$1" in
'instance')
instance
;;
'instances')
instances
;;
'offline')
offline
;;
'online')
online
;;
*)
usage
exit 1
;;
esac
exit 0
njmon 結(jié)果格式化
njmon與nmon類似，但輸出為 JSON 格式，用于服務(wù)器性能統(tǒng)計(jì)。
$ njmon -s 1 -c 1 | jq .
{
"timestamp": {
"datetime": "2020-03-14T19:59:22",
"UTC": "2020-03-14T11:59:22",
"snapshot_seconds": 1,
"snapshot_maxloops": 1,
"snapshot_loop": 0
},
..... 省略其他輸出
}
擴(kuò)展閱讀
- jq 官網(wǎng)：https://stedolan.github.io/jq
- jq 在線運(yùn)行：https://jqplay.org/
