Flow PHP

Baggage implements Countable

Read onlyYes

FinalYes

Key-value store for data propagation across process boundaries.

Baggage allows you to propagate arbitrary data along with a trace, similar to HTTP headers but specifically designed for distributed tracing.

All operations return new Baggage instances (immutable).

Example usage:

$baggage = new Baggage(['user.id' => '12345']);
$baggage = $baggage->with('request.id', 'abc-123');
echo $baggage->get('user.id'); // "12345"

Interfaces

Countable

Methods

__construct() : mixed
all() : array<string, string>: Get all entries.
count() : int: Get the number of entries.
fromArray() : self: Create a Baggage from a normalized array representation.
get() : null|string: Get the value of an entry.
has() : bool: Check if an entry exists.
isEmpty() : bool: Check if the baggage is empty.
normalize() : array{entries: array}: Normalize the Baggage to an array representation for serialization.
with() : self: Create a new Baggage with an additional entry.
without() : self: Create a new Baggage without the specified entry.

__construct()


    public
                    __construct([array<string, string> $entries = [] ]) : mixed

Parameters

$entries : array<string, string> = []

all()

Get all entries.


    public
                    all() : array<string, string>

Return values

array<string, string>

count()

Get the number of entries.


    public
                    count() : int

Return values

int

fromArray()

Create a Baggage from a normalized array representation.


    public
            static        fromArray(array{entries: array} $data) : self

Parameters

$data : array{entries: array}: Normalized Baggage data

Return values

self

get()

Get the value of an entry.


    public
                    get(string $key) : null|string

Parameters

$key : string: Entry key

Return values

null|string —

The entry value, or null if not found

has()

Check if an entry exists.


    public
                    has(string $key) : bool

Parameters

$key : string: Entry key

Return values

bool

isEmpty()

Check if the baggage is empty.


    public
                    isEmpty() : bool

Return values

bool

normalize()

Normalize the Baggage to an array representation for serialization.


    public
                    normalize() : array{entries: array}

Return values

array{entries: array}

with()

Create a new Baggage with an additional entry.


    public
                    with(string $key, string $value) : self

If the key already exists, its value will be replaced.

Parameters

$key : string: Entry key
$value : string: Entry value

Return values

self —

New Baggage instance with the added entry

without()

Create a new Baggage without the specified entry.


    public
                    without(string $key) : self

Parameters

$key : string: Entry key to remove

Return values

self —

New Baggage instance without the entry