GameServer.Limits (game_server_core v1.0.958)

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Central module for configurable validation limits.

All limits have sensible defaults and can be overridden at boot time via config :game_server_core, GameServer.Limits, key: value or at runtime via Application.put_env(:game_server_core, GameServer.Limits, [...]).

Environment variables

Each limit can be set via an environment variable. The env var name maps to the limit key with an uppercase LIMIT_ prefix, e.g.:

LIMIT_MAX_METADATA_SIZE=32768   -> :max_metadata_size
LIMIT_MAX_PAGE_SIZE=100         -> :max_page_size

Env vars are read once at boot in config/runtime.exs.

Usage in schemas

import GameServer.Limits, only: [get: 1, validate_metadata_size: 2]

changeset
|> validate_length(:title, max: GameServer.Limits.get(:max_group_title))
|> validate_metadata_size(:metadata)

Usage in controllers

page_size = GameServer.Limits.clamp_page_size(params["page_size"])

Summary

Functions

all()

Returns a map of all limit keys and their current effective values.

clamp_page(raw)

Clamps a raw page parameter to [1, ∞). Same parsing logic as page_size.

clamp_page_size(raw, default \\ 25)

Clamps a raw page_size parameter to [1, max_page_size]. Accepts nil, string, or integer. Returns integer.

defaults()

Returns the compiled defaults map. Useful for the admin UI to display defaults vs. overrides.

get(key)

Returns the current value for the given limit key.

validate_metadata_size(changeset, field, limit_key \\ :max_metadata_size)

Validates that a :map field, when serialized to JSON, does not exceed max_metadata_size bytes. Add this to any changeset that casts a metadata or arbitrary JSON map field.

Functions

all()

@spec all() :: map()

Returns a map of all limit keys and their current effective values.

clamp_page(raw)

@spec clamp_page(any()) :: pos_integer()

Clamps a raw page parameter to [1, ∞). Same parsing logic as page_size.

clamp_page_size(raw, default \\ 25)

@spec clamp_page_size(any(), integer()) :: integer()

Clamps a raw page_size parameter to [1, max_page_size]. Accepts nil, string, or integer. Returns integer.

defaults()

@spec defaults() :: map()

Returns the compiled defaults map. Useful for the admin UI to display defaults vs. overrides.

get(key)

@spec get(atom()) :: integer() | any()

Returns the current value for the given limit key.

Reads from Application.get_env(:game_server_core, GameServer.Limits) first, falling back to the compiled default.

validate_metadata_size(changeset, field, limit_key \\ :max_metadata_size)

@spec validate_metadata_size(Ecto.Changeset.t(), atom(), atom()) :: Ecto.Changeset.t()

Validates that a :map field, when serialized to JSON, does not exceed max_metadata_size bytes. Add this to any changeset that casts a metadata or arbitrary JSON map field.

changeset
|> validate_metadata_size(:metadata)
|> validate_metadata_size(:value, :max_kv_value_size)