Parsing complex JSON, again - json

Question

I have some JSON that get via an API call and I want to now parse this using JSON, I followed an online tutorial in how to parse JSON using structs, but my actual JSON is a lot more complex than the one they used. Here is an example of the JSON I have:
{
"metadata": {},
"items": [
{
"metadata": {
"name": "run7",
"namespace": "default",
"uid": "e218fcc4",
"creationTimestamp": "2022-01-01T00:00:00Z"
},
"spec": {
"arguments": {}
},
"status": {
"phase": "Succeeded",
"startedAt": "2022-01-01T00:00:00Z",
"finishedAt": "2022-01-01T00:00:00Z"
}
}
]
}
and here is the strucs that I created for it:
type wfSpec struct{
Arguments string
}
type wfStatus struct {
Phase string
StartedAt string
FinishedAt string
}
type wfMetadata struct {
Name string
Namespace string
Uid string
CreationTimestamp string
}
type Metadata []struct {
Data string
}
type Items []struct {
wfMetadata
wfStatus
wfSpec
}
type Workflow struct {
Metadata Metadata
Items Items
}
When I first tried to print a value using fmt.Printf(workflows.Items.wfMetadata.Name) I got the error workflows.Items.Metadata undefined (type Items has no field or method Metadata)so then I tried to just print the whole thing using fmt.Printf(workflows) and I got this error cannot use workflows (type Workflow) as type string in argument to fmt.Printf
The only data I need to parse from the JSON is the
"name": "run7",
"namespace": "default",
"uid": "e218fcc4",
"creationTimestamp": "2022-01-01T00:00:00Z"

Answer 1

First off
The problem I expect you're having is not using the tags. To parse a JSON the names of the structs must match the names in the JSON fields. Read here Golang Marshal
Secondly wfMetadata has a lowecase first letter, meaning it will not be imported.
Thirdly, workflow.metadata and workflow.items[i].spec.arguments is set as a {} and not the emptystring "". I assume they're not supposed to be string. This can be avoided using the open interface{} if you don't know or care, or actually implementing them using the official documentations from the API you're connecting to.
As a note, using []struct seems wrong to me. Instead define it in the usage
Note, by using an IDE like GoLand from jetbrains they first off support converting JSON to a struct by simply pasting the JSON into a .go file. They might be daunting at first but do help a lot, and would do much of this for you in seconds.
Now try this instead, and understand why and how this is better and working.
type Status struct {
Phase string `json:"phase"`
StartedAt string `json:"startedAt"`
FinishedAt string `json:"finishedAt"`
}
type ItemMetadata struct {
Name string `json:"name"`
Namespace string `json:"namespace"`
UID string `json:"uid"`
CreationTimestamp string `json:"creationTimestamp"`
}
type Items struct {
Metadata ItemMetadata `json:"metadata"`
Status Status `json:"status"`
Spec interface{} `json:"spec"`
}
type Workflow struct {
Metadata interface{} `json:"metadata"`
Items []Items `json:"items"`
}
Working example in playground https://go.dev/play/p/d9rT4FZJsGv