#[non_exhaustive]pub enum RdsdbMetricName {
Cpu,
DatabaseConnections,
EbsVolumeReadIops,
EbsVolumeReadThroughput,
EbsVolumeStorageSpaceUtilization,
EbsVolumeWriteIops,
EbsVolumeWriteThroughput,
Memory,
NetworkReceiveThroughput,
NetworkTransmitThroughput,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against RdsdbMetricName
, it is important to ensure
your code is forward-compatible. That is, if a match arm handles a case for a
feature that is supported by the service but has not been represented as an enum
variant in a current version of SDK, your code should continue to work when you
upgrade SDK to a future version in which the enum does include a variant for that
feature.
Here is an example of how you can make a match expression forward-compatible:
# let rdsdbmetricname = unimplemented!();
match rdsdbmetricname {
RdsdbMetricName::Cpu => { /* ... */ },
RdsdbMetricName::DatabaseConnections => { /* ... */ },
RdsdbMetricName::EbsVolumeReadIops => { /* ... */ },
RdsdbMetricName::EbsVolumeReadThroughput => { /* ... */ },
RdsdbMetricName::EbsVolumeStorageSpaceUtilization => { /* ... */ },
RdsdbMetricName::EbsVolumeWriteIops => { /* ... */ },
RdsdbMetricName::EbsVolumeWriteThroughput => { /* ... */ },
RdsdbMetricName::Memory => { /* ... */ },
RdsdbMetricName::NetworkReceiveThroughput => { /* ... */ },
RdsdbMetricName::NetworkTransmitThroughput => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when rdsdbmetricname
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant RdsdbMetricName::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
RdsdbMetricName::Unknown(UnknownVariantValue("NewFeature".to_owned()))
and calling as_str
on it yields "NewFeature"
.
This match expression is forward-compatible when executed with a newer
version of SDK where the variant RdsdbMetricName::NewFeature
is defined.
Specifically, when rdsdbmetricname
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on RdsdbMetricName::NewFeature
also yielding "NewFeature"
.
Explicitly matching on the Unknown
variant should
be avoided for two reasons:
- The inner data
UnknownVariantValue
is opaque, and no further information can be extracted. - It might inadvertently shadow other intended match arms.
Variants (Non-exhaustive)§
This enum is marked as non-exhaustive
Cpu
DatabaseConnections
EbsVolumeReadIops
EbsVolumeReadThroughput
EbsVolumeStorageSpaceUtilization
EbsVolumeWriteIops
EbsVolumeWriteThroughput
Memory
NetworkReceiveThroughput
NetworkTransmitThroughput
Unknown(UnknownVariantValue)
Unknown
. See the docs on this enum for the correct way to handle unknown variants.Unknown
contains new variants that have been added since this code was generated.
Implementations§
source§impl RdsdbMetricName
impl RdsdbMetricName
sourcepub fn try_parse(value: &str) -> Result<Self, UnknownVariantError>
pub fn try_parse(value: &str) -> Result<Self, UnknownVariantError>
Parses the enum value while disallowing unknown variants.
Unknown variants will result in an error.
Trait Implementations§
source§impl AsRef<str> for RdsdbMetricName
impl AsRef<str> for RdsdbMetricName
source§impl Clone for RdsdbMetricName
impl Clone for RdsdbMetricName
source§fn clone(&self) -> RdsdbMetricName
fn clone(&self) -> RdsdbMetricName
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for RdsdbMetricName
impl Debug for RdsdbMetricName
source§impl Display for RdsdbMetricName
impl Display for RdsdbMetricName
source§impl From<&str> for RdsdbMetricName
impl From<&str> for RdsdbMetricName
source§impl FromStr for RdsdbMetricName
impl FromStr for RdsdbMetricName
source§impl Hash for RdsdbMetricName
impl Hash for RdsdbMetricName
source§impl Ord for RdsdbMetricName
impl Ord for RdsdbMetricName
source§fn cmp(&self, other: &RdsdbMetricName) -> Ordering
fn cmp(&self, other: &RdsdbMetricName) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
source§impl PartialEq for RdsdbMetricName
impl PartialEq for RdsdbMetricName
source§impl PartialOrd for RdsdbMetricName
impl PartialOrd for RdsdbMetricName
impl Eq for RdsdbMetricName
impl StructuralPartialEq for RdsdbMetricName
Auto Trait Implementations§
impl Freeze for RdsdbMetricName
impl RefUnwindSafe for RdsdbMetricName
impl Send for RdsdbMetricName
impl Sync for RdsdbMetricName
impl Unpin for RdsdbMetricName
impl UnwindSafe for RdsdbMetricName
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
source§unsafe fn clone_to_uninit(&self, dst: *mut T)
unsafe fn clone_to_uninit(&self, dst: *mut T)
clone_to_uninit
)source§impl<Q, K> Comparable<K> for Q
impl<Q, K> Comparable<K> for Q
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.source§impl<T> Instrument for T
impl<T> Instrument for T
source§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
source§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
source§impl<T> IntoEither for T
impl<T> IntoEither for T
source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left
is true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moresource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left(&self)
returns true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read more