Struct exonum::runtime::migrations::MigrationContext

#[non_exhaustive]pub struct MigrationContext {
    pub helper: MigrationHelper,
    pub instance_spec: InstanceSpec,
    pub data_version: Version,
}

Context of a migration.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

helper: MigrationHelper

The migration helper allowing to access service data and prepare migrated data.

instance_spec: InstanceSpec

Specification of the migrated instance.

data_version: Version

Version of the service data.

Note that the artifact version will change with each executed MigrationScript to reflect the latest version of the service data. For example, if a MigrateData implementation produces two scripts, which migrate service data to versions 0.5.0 and 0.6.0 respectively, then the second script will get the data_version set to 0.5.0, regardless of the original version of the instance artifact.

Trait Implementations

impl Debug for MigrationContext

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.