Struct MigratorBuilder

pub struct MigratorBuilder<P, T, FRO, FRN, FWO, FWN>
where
    P: Send + Sync,
    T: Send + Sync,
    FRO: Fn(&P) -> BoxFuture<'_, Result<T, String>> + Sync + Send,
    FRN: Fn(&P) -> BoxFuture<'_, Result<T, String>> + Sync + Send,
    FWO: Fn(&P) -> BoxFuture<'_, Result<T, String>> + Sync + Send,
    FWN: Fn(&P) -> BoxFuture<'_, Result<T, String>> + Sync + Send,
{ /* private fields */ }

The migration builder is used to configure and construct an instance of a Migrator. This migrator can be used to perform LaunchDarkly assisted technology migrations through the use of migration-based feature flags.

Implementations

impl<P, T, FRO, FRN, FWO, FWN> MigratorBuilder<P, T, FRO, FRN, FWO, FWN>

where P: Send + Sync, T: Send + Sync, FRO: Fn(&P) -> BoxFuture<'_, Result<T, String>> + Sync + Send, FRN: Fn(&P) -> BoxFuture<'_, Result<T, String>> + Sync + Send, FWO: Fn(&P) -> BoxFuture<'_, Result<T, String>> + Sync + Send, FWN: Fn(&P) -> BoxFuture<'_, Result<T, String>> + Sync + Send,

pub fn new(client: Arc<Client>) -> Self

Create a new migrator builder instance with the provided client.

pub fn read_execution_order(self, order: ExecutionOrder) -> Self

The read execution order influences the concurrency and execution order for read operations involving multiple origins.

pub fn track_latency(self, measure: bool) -> Self

Enable or disable latency tracking for migration operations. This latency information can be sent upstream to LaunchDarkly to enhance migration visibility.

pub fn track_errors(self, measure: bool) -> Self

Enable or disable error tracking for migration operations. This error information can be sent upstream to LaunchDarkly to enhance migration visibility.

pub fn read( self, old: FRO, new: FRN, compare: Option<fn(&T, &T) -> bool>, ) -> Self

Read can be used to configure the migration-read behavior of the resulting Migrator instance.

Users are required to provide two different read methods – one to read from the old migration origin, and one to read from the new origin. Additionally, users can opt-in to consistency tracking by providing a comparison function.

Depending on the migration stage, one or both of these read methods may be called.

pub fn write(self, old: FWO, new: FWN) -> Self

Write can be used to configure the migration-write behavior of the resulting crate::Migrator instance.

Users are required to provide two different write methods – one to write to the old migration origin, and one to write to the new origin. Not every stage requires

Depending on the migration stage, one or both of these write methods may be called.

pub fn build(self) -> Result<Migrator<P, T, FRO, FRN, FWO, FWN>, String>

Build constructs a crate::Migrator instance to support migration-based reads and writes. A string describing any failure conditions will be returned if the build fails.