Idempotency key generation and management.
Column supports idempotent POST requests via the Idempotency-Key header.
Keys are stored for 30 days and must be:
- Maximum 255 characters
- ASCII printable characters only
The Column client auto-generates a random key for every POST request. Use this module when you need deterministic, business-logic-derived keys.
Strategies
UUID (default — random, non-deterministic)
key = Column.Idempotency.uuid()
Column.ACH.create(%{...}, idempotency_key: key)Deterministic (content-addressed)
Use when the same business operation must map to the same key, even across process restarts or retries from a job queue:
key = Column.Idempotency.for_transfer(:ach, order_id: "ord_123", attempt: 1)
# => "ach:ord_123:1"
key = Column.Idempotency.hash("ach", %{order_id: "ord_123", amount: 10_000})
# => "ach:a3f2c8..." (SHA256-derived, always same for same inputs)Namespaced
key = Column.Idempotency.namespaced("payroll", "run_456", "june-2024")
# => "payroll:run_456:june-2024"Validation
Column.Idempotency.valid?("my-key") # => true
Column.Idempotency.valid?("x" <> String.duplicate("a", 255)) # => false (too long)Summary
Functions
Build a key from keyword list of fields.
Build a deterministic content-addressed key from a namespace and a map of params.
Build a namespaced idempotency key from parts.
Generate a random UUID v4 idempotency key.
Returns true if the key is valid for use as an idempotency key.
Functions
Build a key from keyword list of fields.
Build a deterministic content-addressed key from a namespace and a map of params.
The map is JSON-encoded, SHA256-hashed, and prefixed with the namespace. This produces the same key for the same logical operation across retries.
Column.Idempotency.hash("ach_credit", %{order_id: "ord_123", amount: 5000})
# => "ach_credit:3d2e1f..."Build a namespaced idempotency key from parts.
All parts are joined with : and validated.
Column.Idempotency.namespaced("payroll", "run_456", "2024-06")
# => "payroll:run_456:2024-06"@spec uuid() :: String.t()
Generate a random UUID v4 idempotency key.
Returns true if the key is valid for use as an idempotency key.