### Create Pydantic *models* / schemas for reading / returning

Now create Pydantic *models* (schemas) that will be used when reading data, when returning it from the API.

For example, before creating an item, we don't know what will be the ID assigned to it, but when reading it (when returning it from the API) we will already know its ID.

### Creating the `Settings` only once with `lru_cache`

Reading a file from disk is normally a costly (slow) operation, so you probably want to do it only once and then re-use the same settings object, instead of reading it for each request.

But every time we do:

```Python
Settings()
```

	flag.IntVar(&port, "port", 8080, "Port to listen on")
}

func mainHandler(w http.ResponseWriter, r *http.Request) {
	body, err := io.ReadAll(r.Body)
	defer r.Body.Close()
	if err != nil {
		log.Printf("Error reading request body: %v", err)
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	log.Printf(">>> %s %s\n", r.Method, r.URL.Path)
	var out bytes.Buffer
	json.Indent(&out, body, "", "    ")

// for io.EOF.
//
// If an EOF happens after reading some but not all the bytes,
// ReadFile returns ErrUnexpectedEOF.
//
// If the BitrotVerifier is not nil or not verified ReadFile
// tries to verify whether the disk has bitrot.
//
// Additionally ReadFile also starts reading from an offset. ReadFile
// semantics are same as io.ReadFull.

	readerIndex := 0
	var wg sync.WaitGroup
	// if readTrigger is true, it implies next disk.ReadAt() should be tried
	// if readTrigger is false, it implies previous disk.ReadAt() was successful and there is no need
	// to try reading the next disk.
	for readTrigger := range readTriggerCh {
		newBufLK.RLock()
		canDecode := p.canDecode(newBuf)
		newBufLK.RUnlock()
		if canDecode {
			break
		}
		if readerIndex == len(p.readers) {

			//    https://blog.cloudflare.com/when-tcp-sockets-refuse-to-die/
			// This is a sensitive configuration, it is better to set it to high values, > 60 secs since it can
			// affect clients reading data with a very slow pace  (disappropriate with socket buffer sizes)
			_ = syscall.SetsockoptInt(fd, syscall.IPPROTO_TCP, unix.TCP_USER_TIMEOUT, opts.UserTimeout)

			if opts.Interface != "" {

	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	randInterval := func() time.Duration {
		return time.Duration(r.Float64() * 5 * float64(time.Second))
	}

	// To avoid all MinIO nodes reading the tier config object at the same
	// time.
	t := time.NewTimer(tierCfgRefresh + randInterval())
	defer t.Stop()
	for {
		select {
		case <-ctx.Done():
			return
		case <-t.C:

the policy propagation from Istiod to Envoy and the final AuthorizationPolicy list merged
from multiple sources (mesh-level, namespace-level and workload-level).

The command also supports reading from a standalone config dump file with flag -f.`,
		Example: `  # Check AuthorizationPolicy applied to pod httpbin-88ddbcfdd-nt5jb:
  istioctl x authz check httpbin-88ddbcfdd-nt5jb

	Files        []string // Individual files to read.
	MaxSize      int64    // Return error if size is exceed.
	MetadataOnly bool     // Read as XL meta and truncate data.
	AbortOn404   bool     // Stop reading after first file not found.
	MaxResults   int      // Stop after this many successful results. <= 0 means all.
}

// ReadMultipleResp contains a single response from a ReadMultipleReq.
type ReadMultipleResp struct {

The **Advanced User Guide**, builds on this, uses the same concepts, and teaches you some extra features.

But you should first read the **Tutorial - User Guide** (what you are reading right now).