bash 使用 jq 遍历 json 以获取多个值
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Loop through json using jq to get multiple value
提问by sylye
Here is volumes.json :
这是volumes.json：
{
"Volumes": [
{
"AvailabilityZone": "us-east-1a",
"Tags": [
{
"Value": "vol-rescue-system",
"Key": "Name"
}
],
"VolumeId": "vol-00112233",
},
{
"AvailabilityZone": "us-east-1a",
"Tags": [
{
"Value": "vol-rescue-swap",
"Key": "Name"
}
],
"VolumeId": "vol-00112234",
},
{
"AvailabilityZone": "us-east-1a",
"Tags": [
{
"Value": "vol-rescue-storage",
"Key": "Name"
}
],
"VolumeId": "vol-00112235",
}
]
}
I need to get both the value of VolumeIdand Tags.Valueto be used as the input to invoke another command. It is easy to get a single value from the json array, but I am not able to extract multiple valuefrom it and pass it to another bash command.
我需要得到双方的价值VolumeId，并Tags.Value用作输入来调用另一个命令。从 json 数组中获取单个值很容易，但我无法从中提取多个值并将其传递给另一个 bash 命令。
I can get a single value using this:
我可以使用这个获得单个值：
cat volumes.json |jq -r '.Volumes[].VolumeId' |while read v; do another_bash_command $v; done
but I am not able to get multiple value cause this is wrong:
但我无法获得多个值，因为这是错误的：
cat volumes.json |jq -r '.Volumes[].VolumeId, .Volumes[].Tags[].Value' |while read v w; do another_bash_command $v $w; done
as it will then loop 6 times of the outcome instead of 3.
因为它将循环结果的 6 次而不是 3 次。
And, how do I pass those multiple json value in the loop to a bash array so I can use the value in a better way ? Like VolumeId-> $arr[0][0], Tags.Value-> $arr[0][1], AvailabilityZone-> $arr[0][2]...etc. I have searched through SO and the jq docs, and tried readarray, but still not able to find out the solution :( Thanks for any help given.
而且，如何将循环中的多个 json 值传递给 bash 数组，以便我可以更好地使用该值？比如VolumeId-> $arr[0][0], Tags.Value-> $arr[0][1], AvailabilityZone-> $arr[0][2]... 等等。我已经搜索过 SO 和 jq 文档，并尝试过readarray，但仍然无法找到解决方案:( 感谢您提供的任何帮助。
回答by andlrc
It seems to me that you want to output the two values (VolumeIdand Tags[].Value) on the same line?
在我看来，您想在同一行上输出两个值 (VolumeId和Tags[].Value)？
If that's the case, then a simple string concatenation should be enough:
如果是这种情况，那么简单的字符串连接就足够了：
$ jq -r '.Volumes[] | .VolumeId + " " + .Tags[].Value' volumes.json
vol-00112233 vol-rescue-system
vol-00112234 vol-rescue-swap
vol-00112235 vol-rescue-storage
The above can then be used in a pipeline with while-read:
然后可以在管道中使用上述内容while-read：
$ cat my_script
jq -r '.Volumes[] | .VolumeId + " " + .Tags[].Value' volumes.json \
| while IFS= read -r volumeId tagValue; do
other_command "$volumeId" "$tagValue"
done
You should note that if there is more than one element in Tagsthe result will reflect that. This can however be avoided by referring the first element in Tags: .Tags[0].Value
您应该注意，如果结果中有多个元素Tags会反映出来。然而，这可以通过引用中的第一个元素来避免Tags：.Tags[0].Value
回答by peak
As @andlrc observed, you may need to decide what you really want in the event that any Tags array has more or less than one element. Assuming you want Tags[0]in all cases, I would recommend considering the use of @tsv as follows:
正如@andlrc 所观察到的，如果任何标签数组的元素多于或少于一个，您可能需要决定您真正想要什么。假设您Tags[0]在所有情况下都想要，我建议您考虑使用 @tsv，如下所示：
jq -r '.Volumes[] | [.VolumeId, .Tags[0].Value] | @tsv' volumes.json
This would be especially appropriate if any of the .VolumeIdor .Tags[0].Valuevalues contained spaces, tabs, newlines, etc. The point is that @tsv will handle these in a standard way, so that handling the pair of values can be done in a standard way as well. E.g. using awk, you could read in the pair with awk -F\\t; using bash, IFS=$'\t', etc.
如果.VolumeId或.Tags[0].Value值中的任何一个包含空格、制表符、换行符等，这将特别合适。关键是@tsv 将以标准方式处理这些，因此也可以以标准方式处理这对值. 例如，使用 awk，您可以使用awk -F\\t; 使用 bashIFS=$'\t'等
回答by Frederic Henri
I know the question is about how to get the information using jqbut its also possible to directly get the expected parameter directly from aws cli using the --queryflag.
我知道问题是关于如何使用信息获取信息，jq但也可以使用--query标志直接从 aws cli 直接获取预期参数。
aws ec2 describe-volumes --query "Volumes[].[VolumeId, Tags[].Value]" --output text
