IV.1 No "magic" values

Timeouts, retries, sizes, limits, TTLs and thresholds are set once by a named constant or a config field and reused. A literal in an attribute is allowed only if it occurs in the program once and its meaning is obvious from the context (analyzer: magic-literal).

Bad:

oxl

@timeout(3s) rpc get(id: UserId) -> User
@timeout(3s) rpc list(page: u32) -> List<User>
@timeout(3s) @retry(3) rpc create(…) -> User

Good:

oxl

// src/limits/limits.oxl — a single place for default values
pub const STD_TIMEOUT    = 3s
pub const LONG_TIMEOUT   = 30s
pub const STD_RETRIES    = 3
pub const PAGE_SIZE: u32 = 50

@timeout(STD_TIMEOUT) rpc get(id: UserId) -> User
@timeout(STD_TIMEOUT) rpc list(page: u32) -> List<User>
@timeout(STD_TIMEOUT) @retry(STD_RETRIES) @idempotent rpc create(…) -> User

Even better — set the common value in cluster { defaults { timeout STD_TIMEOUT } } and write @timeout only where the value differs.

Where to put a value:

Value	Where
known at build time and independent of the environment	a `const` in the module `limits` or next to its use
depends on the environment (addresses, keys, ports)	`config` (§14.1)
changes at run time without a restart (limits, flags)	`dynamic` (§14.2)
the same for all rpcs of the cluster	`cluster { defaults { … } }`

magic-literal

Source: docs/spec/oxl-standard.en.md

IV.1 No "magic" values

Related diagnostics