Question: How can I parse multi yaml file?

[wrbbz]

Hello!
I've got a file with multiple yaml objects with the same structure. It looks like this:

---
apiVersion: ...
kind: ...
metadata:
  description: ...
spec:
  type: ...
---
apiVersion: ...
kind: ...
metadata:
  description: ...
spec:
  type: ...
---
. . .

I would like to parse each object separately and make some processing (i.e. validation)

I've tried the following approach ():

file, err := os.Open(yamlFile)
if err != nil {
  log.Fatal(err)
}

for {
  var yamlObject any
  dec := yaml.NewDecoder(file)
  if err := dec.Decode(&yamlObject); err != nil {
    log.Fatalf("Decoding error: %s", err)
  }

// some processing goes here

}

However, this parses only the first yaml block inside the file and the second iteration of for loop failes with EOF.

I've noticed this solution (somewhat like this) here. I understand, that this solution for another go-yaml, however, I would like to use this implementation

Also, I've noticed this issue which is also about multi-yaml file, so I've tried to initialize File type:

f, err := os.ReadFile(instanceFile)
if err != nil {
  log.Fatal(err)
}

var file ast.File
if _, err := file.Read(f); err != nil {
  log.Fatalln(err)
}

log.Println(len(file.Docs))

And all I've got is EOF

So, how can I properly parse multi-yaml file?

[goccy]

@wrbbz Your usage is incorrect. Similar to Go's standard library, yaml.NewDecoder must be initialized outside of the loop.

[wrbbz]

@goccy, yeeaaah. That makes a lot of sense. My bad. Thank you for pointing that out

Maybe, you can also point out what is wrong with the initialisation of ast.File in the code block above?

[Roemer]

In case anyone wonders, here is an example that worked for me:

file, err := os.Open(yamlFile)
if err != nil {
  log.Fatal(err)
}

dec := yaml.NewDecoder(file)
for {
  var yamlObject any
  if err := dec.Decode(&yamlObject); err != nil {
    if errors.Is(err, io.EOF) {
      break
    }
    log.Fatalf("Decoding error: %s", err)
  }
  // Process the item yamlObject 
}