How to construct nested JSON using for loops and arenapools?

[clarencefoy]

Hi, I am currently having to construct a JSON file containing three things. Instances, versions and function names.

Each instance has a version, each version has multiple function names.

Therefore, each 'version' is an array. Each 'instance' has multiple versions.

In pseudocode, I would append each 'function name' to an array (which will be 'version'), and then I would set a key within 'instance' to the 'version', which holds this array of 'function name'.

The problem is that I can't for the life of me figure out how to use the ArenaPool approach to make this safe. It would appear I am always ending up with the 'version' array containing the entries of the last for loop that has been iterated through.

See the following code:

    instances := []Stat{}
    versions := []Stat{}
    functions := []Stat{}
    var ap fastjson.ArenaPool
    are := ap.Get()
    verJSON := are.NewObject()
    instJSON := are.NewObject()

    err := sts.db.Select(&instances, "select distinct on (instance) instance from stats")
    if err != nil {
        [handle error]
        return nil, err
    }

    for _, inst := range instances {
        err := sts.db.Select(&versions, "select distinct on (version) version from stats WHERE instance = $1", inst.Instance)
        if err != nil {
            [handle error]
            return nil, err
        }
        for _, ver := range versions {
            err := sts.db.Select(&functions, "select distinct on (func_name) func_name from stats where instance = $1 and version = $2", inst.Instance, ver.Version)
            if err != nil {
                [handle error]
                return nil, err
            }
            newAr := ap.Get()
            defer ap.Put(newAr)
            arr := newAr.NewArray()
            for i, fun := range functions {
                arr.SetArrayItem(i, newAr.NewString(fun.FuncName))
            }
            verJSON.Set(ver.Version, arr)
            functions = nil
            instJSON.Set(inst.Instance, verJSON)
        }
        versions = nil
    }

    fmt.Println("This is instJSON: ", instJSON)

'instJSON' always ends up containing the 'verJSON' from the second to last and last loop of 'range instances'.