How to add value to array with JMESPath?

Question

With the following JSON:

{
   "resource_access":{
      "info-bi-test":{
         "roles":[
            "DB7"
         ]
      }
   }
}

How to add another value to an array resource_access."info-bi-test".roles with JMESPath?

I read the documentation of JMESPath and found the merge function, but it only works with objects.

How do you want to declare which list should be an item added to? Imagine, there might `{"roles1":["DB7"], "roles2":["XP7"]}`. — Vladimir Botka, Mar 29 '23 at 14:39

β.εηοιτ.βε · Answer 1 · 2023-03-29T19:08:40.113

The basic idea to add item(s) to an existing array is to create an array of array(s) and then flatten it.

As an example, a totally static query like

[['a', 'b', 'c'], ['d', 'e']][]

Will give:

[
  "a",
  "b",
  "c",
  "d",
  "e"
]

Now, since you are not giving a desired output, there are multiple cases:

You want to add one hardcoded item to the array resource_access."info-bi-test".roles, and have a simple array as return, with a desired output like
```
["DB7", "DB9"]
```
Then, this could be achieved with the query:
```
[resource_access."info-bi-test".roles, 'DB9'][]
```
You want to add multiple items to the array resource_access."info-bi-test".roles, and have a simple array as return, with a desired output like
```
["DB7", "DB9", "DB11"]
```
Then, this could be achieved with the query:
```
[resource_access."info-bi-test".roles, ['DB9', 'DB11']][]
```
You want to add one item to the array resource_access."info-bi-test".roles form somewhere else in the JSON structure, with an input like
```
{
  "resource_access":{
    "info-bi-test":{
      "roles":[
        "DB7"
      ]
    }
  },
  "default_role": "DB9"
}
```
and have a simple array as return, with a desired output like
```
["DB7", "DB9"]
```
Then, this could be achieved with the query:
```
[resource_access."info-bi-test".roles, default_role][]
```
You want to add multiple items to the array resource_access."info-bi-test".roles form somewhere else in the JSON structure, with an input like
```
{
  "resource_access": {
    "info-bi-test": {
      "roles":[
        "DB7"
      ]
    }
  },
  "default_roles": [
    "DB9",
    "DB11"
  ]
}
```
and have a simple array as return, with a desired output like
```
["DB7", "DB9", "DB11"]
```
Then, this could be achieved with the query:
```
[resource_access."info-bi-test".roles, default_roles][]
```

You want to add one hardcoded item to the array resource_access."info-bi-test".roles, but you want the whole object structure returned, with a desired output like

{
  "resource_access": {
    "info-bi-test": {
      "roles": [
        "DB7",
        "DB9"
      ]
    }
  }
}

Then, you will have to recreate the object structure in the query:

{
  resource_access: {
    "info-bi-test": {
      roles: [resource_access."info-bi-test".roles, 'DB9'][]
    }
  }
}

You want to add multiple hardcoded items to the array resource_access."info-bi-test".roles, but you want the whole object structure returned, with a desired output like

{
  "resource_access":{
    "info-bi-test":{
      "roles":[
        "DB7",
        "DB9",
        "DB11"
      ]
    }
  }
}

Then, you will have to recreate the object structure in the query:

{
  resource_access: {
    "info-bi-test": {
      roles: [resource_access."info-bi-test".roles, ['DB9', 'DB11']][]
    }
  }
}

You want to add one item to the array resource_access."info-bi-test".roles form somewhere else in the JSON structure, with an input like

{
  "resource_access":{
    "info-bi-test":{
      "roles":[
        "DB7"
      ]
    }
  },
  "default_role": "DB9"
}

but you want the whole object structure returned, with a desired output like

{
  "resource_access":{
    "info-bi-test":{
      "roles":[
        "DB7",
        "DB9"
      ]
    }
  }
}

Then, you will have to recreate the object structure in the query:

{
  resource_access: {
    "info-bi-test": {
      roles: [resource_access."info-bi-test".roles, default_role][]
    }
  }
}

You want to add multiple items to the array resource_access."info-bi-test".roles form somewhere else in the JSON structure, with an input like

{
  "resource_access":{
    "info-bi-test":{
      "roles":[
        "DB7"
      ]
    }
  },
  "default_roles": [
    "DB9",
    "DB11"
  ]
}

but you want the whole object structure returned, with a desired output like

{
  "resource_access":{
    "info-bi-test":{
      "roles":[
        "DB7",
        "DB9",
        "DB11"
      ]
    }
  }
}

Then, you will have to recreate the object structure in the query:

{
  resource_access: {
    "info-bi-test": {
      roles: [resource_access."info-bi-test".roles, default_roles][]
    }
  }
}

So, as you can see, they are all flavour of the same principle: nest everything in an array and flatten it.

How to add value to array with JMESPath?

1 Answers1