# Dependencies - `Depends()` and `Security()`

## `Depends()`

Dependencies are handled mainly with the special function `Depends()` that takes a callable.

Here is the reference for it and its parameters.

You can import it directly from `fastapi`:

```python
from fastapi import Depends
```

::: fastapi.Depends

## `Security()`

package cmd

import (
	"context"
	"errors"
	"fmt"
	"io"
	"strings"

	"github.com/minio/madmin-go/v3"
	xhttp "github.com/minio/minio/internal/http"
)

// WarmBackendGetOpts is used to express byte ranges within an object. The zero
// value represents the entire byte range of an object.
type WarmBackendGetOpts struct {
	startOffset int64
	length      int64
}

	// APIPA/"link-local" IP.
	//
	// It doesn't matter what this IP is, so long as it's not routable and doesn't collide with anything else.
	//
	// IPv6 link local ranges are designed to be collision-resistant by default, and so probably never need to be overridden
	DefaultHostProbeSNATIP   = "169.254.7.127"
	DefaultHostProbeSNATIPV6 = "fd16:9254:7127:1337:ffff:ffff:ffff:ffff"
)

# `HTTPConnection` class

When you want to define dependencies that should be compatible with both HTTP and WebSockets, you can define a parameter that takes an `HTTPConnection` instead of a `Request` or a `WebSocket`.

You can import it from `fastapi.requests`:

```python
from fastapi.requests import HTTPConnection
```

    for (int i = 0; i < grad_outputs.size(); i++) {
      auto grad_input = grad_outputs[i];
      // TODO(srbs): Should we add a copy contructor to AbstractTensorHandle
      // that takes care of this similar to `Tensor`?
      if (grad_input) {
        grad_input->Ref();
      }
      grad_inputs[i] = grad_input;
    }
    return absl::OkStatus();
  }
  ~IdentityNGradientFunction() override {}

### Contêiner Único

Se você tiver uma configuração simples, com um **único contêiner** que então inicia vários **processos trabalhadores** (ou também apenas um processo), então poderia executar esses passos anteriores no mesmo contêiner, logo antes de iniciar o processo com o aplicativo. A imagem oficial do Docker suporta isso internamente.

And if there's any other style or consistency need, I'll ask directly for that, or I'll add commits on top with the needed changes.

### Check the code

* Check and read the code, see if it makes sense, **run it locally** and see if it actually solves the problem.

* Then **comment** saying that you did that, that's how I will know you really checked it.

!!! info

### Timer changes

Go 1.23 makes two significant changes to the implementation of
[time.Timer] and [time.Ticker].

First, `Timer`s and `Ticker`s that are no longer referred to by the program
become eligible for garbage collection immediately, even if their
`Stop` methods have not been called.
Earlier versions of Go did not collect unstopped `Timer`s until after
they had fired and never collected unstopped `Ticker`s.

  /** The number of occurrences of each element. */
  private final transient ConcurrentMap<E, AtomicInteger> countMap;

  // This constant allows the deserialization code to set a final field. This holder class
  // makes sure it is not initialized unless an instance is deserialized.
  private static class FieldSettersHolder {
    static final FieldSetter<? super ConcurrentHashMultiset<?>> COUNT_MAP_FIELD_SETTER =

	log.Info("info log")
	log.Warn("warn log")
	log.Error("error log")
	// This will error because stdout cannot sync, but the UDS part should sync
	// Ideally we would fail if the UDS part fails but the error library makes it kind of tricky
	_ = log.Sync()

	// Restore os stdout.
	os.Stdout = stdout
	assert.NoError(t, log.Configure(loggingOptions))

	assert.NoError(t, w.Close())
	out, err := io.ReadAll(r)
	assert.NoError(t, err)