Tink.Cache (Tink v0.1.1)

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Caching layer for Tink API responses.

This module provides intelligent caching for API responses to reduce API calls, improve performance, and stay within rate limits. It uses Cachex for persistent caching with configurable TTLs.

Configuration

config :tink, :cache,
  enabled: true,
  default_ttl: :timer.minutes(5),
  max_size: 1000

Cache TTLs by Resource Type

  • Providers: 1 hour (rarely change)
  • Categories: 1 day (static reference data)
  • User Data / Accounts: 5 minutes
  • Balances: 1 minute (frequently updated)
  • Statistics: 1 hour (aggregated data)
  • Credentials: 30 seconds (status changes frequently)
  • Reports (income/expense/risk): 24 hours (immutable once generated)

Summary

Functions

build_key(components)

Builds a cache key from a list of components joined by :.

clear()

Clears all cached values.

delete(key)

Deletes a value from the cache.

enabled?()

Checks if caching is enabled.

fetch(key, fun, opts \\ [])

Fetches a value from cache, computing it with fun on miss.

get(key)

Gets a value from the cache.

invalidate_user(user_id)

Invalidates all cache entries belonging to a user.

put(key, value, opts \\ [])

Puts a value in the cache with optional TTL or resource type.

stats()

Returns cache statistics, or nil if cache is disabled.

Functions

build_key(components)

@spec build_key([String.t() | atom()]) :: String.t()

Builds a cache key from a list of components joined by :.

"providers:GB" = Tink.Cache.build_key(["providers", "GB"])

clear()

@spec clear() :: :ok | {:error, integer()}

Clears all cached values.

delete(key)

@spec delete(String.t()) :: :ok | {:error, boolean()}

Deletes a value from the cache.

enabled?()

@spec enabled?() :: boolean()

Checks if caching is enabled.

fetch(key, fun, opts \\ [])

@spec fetch(String.t(), (-> {:ok, term()} | {:error, term()}), keyword()) ::
  {:ok, term()} | {:error, term()}

Fetches a value from cache, computing it with fun on miss.

{:ok, providers} = Tink.Cache.fetch("providers:GB", fn ->
  call_api()
end, resource_type: :providers)

get(key)

@spec get(String.t()) :: {:ok, term()} | {:error, term()}

Gets a value from the cache.

Returns {:ok, value} on hit, {:error, :not_found} on miss.

invalidate_user(user_id)

@spec invalidate_user(String.t()) :: :ok

Invalidates all cache entries belonging to a user.

Uses a Stream over Cachex keys to avoid loading all keys into memory at once, making it efficient even for large caches.

All user keys are stored under the "<user_id>:" prefix, so prefix matching is exact and cannot collide with a shorter user ID like "user_1" matching "user_10:...".

put(key, value, opts \\ [])

@spec put(String.t(), term(), keyword()) :: :ok | {:error, term()}

Puts a value in the cache with optional TTL or resource type.

:ok = Tink.Cache.put("providers:GB", providers, resource_type: :providers)
:ok = Tink.Cache.put("custom:key", value, ttl: :timer.minutes(10))

stats()

@spec stats() ::
  %{hit_rate: float(), hits: term(), misses: term(), size: term()} | nil

Returns cache statistics, or nil if cache is disabled.

%{hit_rate: 0.75, hits: 150, misses: 50, size: 45} = Tink.Cache.stats()