How can I extract only the name field from json by using gcloud command?

问题

I am new to gcp and linux. I am trying to get the name from the json format using the gcloud command. Below is the command and output:

gcloud firestore indexes composite list --format=json

Output:

[
  {
    "fields": [
      {
        "fieldPath": "is_active",
        "order": "ASCENDING"
      },
      {
        "fieldPath": "created_at",
        "order": "DESCENDING"
      },
      {
        "fieldPath": "__name__",
        "order": "ASCENDING"
      }
    ],
    "name": "projects/emc-ema-simcs-d-286404/databases/(default)/collectionGroups/customer/indexes/CICAgNjbhowK",
    "queryScope": "COLLECTION",
    "state": "READY"
  }

How can I get the name value using gcloud command. I tried using: gcloud firestore indexes composite list | grep name | awk -F'name: ' '{print $2}' but this didn't give any output.

Please help!

Thanks Pritish

回答1:

Let's assume your tool output doesn't really have an unmatched [ at the start that'd make it invalid JSON as in the example you provided in your question and instead either has both [ and ] or has neither, i.e. it is valid JSON.

If the output starts with [ and ends with ] then you'd use jq as:

gcloud firestore indexes composite list --format=json | jq -r '.[0] .name'

Otherwise you'd use jq as:

gcloud firestore indexes composite list --format=json | jq -r '.name'

For example, using cat file<N> in place of gcloud firestore indexes composite list --format=json which I don't have:

$ cat file1
[
  {
    "fields": [
      {
        "fieldPath": "is_active",
        "order": "ASCENDING"
      },
      {
        "fieldPath": "created_at",
        "order": "DESCENDING"
      },
      {
        "fieldPath": "__name__",
        "order": "ASCENDING"
      }
    ],
    "name": "projects/emc-ema-simcs-d-286404/databases/(default)/collectionGroups/customer/indexes/CICAgNjbhowK",
    "queryScope": "COLLECTION",
    "state": "READY"
  }
]
$
$ cat file1 | jq -r '.[0] .name'
projects/emc-ema-simcs-d-286404/databases/(default)/collectionGroups/customer/indexes/CICAgNjbhowK

$ cat file2
  {
    "fields": [
      {
        "fieldPath": "is_active",
        "order": "ASCENDING"
      },
      {
        "fieldPath": "created_at",
        "order": "DESCENDING"
      },
      {
        "fieldPath": "__name__",
        "order": "ASCENDING"
      }
    ],
    "name": "projects/emc-ema-simcs-d-286404/databases/(default)/collectionGroups/customer/indexes/CICAgNjbhowK",
    "queryScope": "COLLECTION",
    "state": "READY"
  }
$
$ cat file2 | jq -r '.name'
projects/emc-ema-simcs-d-286404/databases/(default)/collectionGroups/customer/indexes/CICAgNjbhowK

回答2:

Finally, I was able to get the name value using the below command:

gcloud firestore indexes composite list --format=json | grep '"name"' | awk -F' ' '{print $2}' | awk -F'"' '{print $2}'

Output:

projects/emc-ema-simcs-d-286404/databases/(default)/collectionGroups/customer/indexes/CICAgNjbhowK

来源：https://stackoverflow.com/questions/63921338/how-can-i-extract-only-the-name-field-from-json-by-using-gcloud-command

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json

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