#[non_exhaustive]pub enum InstanceHealthReason {
InstanceDeregistrationInProgress,
InstanceFailedHealthChecks,
InstanceInvalidState,
InstanceIpUnusable,
InstanceNotInUse,
InstanceNotRegistered,
InstanceResponseCodeMismatch,
InstanceTimeout,
LbInitialHealthChecking,
LbInternalError,
LbRegistrationInProgress,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against InstanceHealthReason
, 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 instancehealthreason = unimplemented!();
match instancehealthreason {
InstanceHealthReason::InstanceDeregistrationInProgress => { /* ... */ },
InstanceHealthReason::InstanceFailedHealthChecks => { /* ... */ },
InstanceHealthReason::InstanceInvalidState => { /* ... */ },
InstanceHealthReason::InstanceIpUnusable => { /* ... */ },
InstanceHealthReason::InstanceNotInUse => { /* ... */ },
InstanceHealthReason::InstanceNotRegistered => { /* ... */ },
InstanceHealthReason::InstanceResponseCodeMismatch => { /* ... */ },
InstanceHealthReason::InstanceTimeout => { /* ... */ },
InstanceHealthReason::LbInitialHealthChecking => { /* ... */ },
InstanceHealthReason::LbInternalError => { /* ... */ },
InstanceHealthReason::LbRegistrationInProgress => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when instancehealthreason
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant InstanceHealthReason::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
InstanceHealthReason::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 InstanceHealthReason::NewFeature
is defined.
Specifically, when instancehealthreason
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on InstanceHealthReason::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
InstanceDeregistrationInProgress
InstanceFailedHealthChecks
InstanceInvalidState
InstanceIpUnusable
InstanceNotInUse
InstanceNotRegistered
InstanceResponseCodeMismatch
InstanceTimeout
LbInitialHealthChecking
LbInternalError
LbRegistrationInProgress
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 InstanceHealthReason
impl InstanceHealthReason
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 InstanceHealthReason
impl AsRef<str> for InstanceHealthReason
source§impl Clone for InstanceHealthReason
impl Clone for InstanceHealthReason
source§fn clone(&self) -> InstanceHealthReason
fn clone(&self) -> InstanceHealthReason
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for InstanceHealthReason
impl Debug for InstanceHealthReason
source§impl Display for InstanceHealthReason
impl Display for InstanceHealthReason
source§impl From<&str> for InstanceHealthReason
impl From<&str> for InstanceHealthReason
source§impl FromStr for InstanceHealthReason
impl FromStr for InstanceHealthReason
source§impl Hash for InstanceHealthReason
impl Hash for InstanceHealthReason
source§impl Ord for InstanceHealthReason
impl Ord for InstanceHealthReason
source§fn cmp(&self, other: &InstanceHealthReason) -> Ordering
fn cmp(&self, other: &InstanceHealthReason) -> 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 InstanceHealthReason
impl PartialEq for InstanceHealthReason
source§fn eq(&self, other: &InstanceHealthReason) -> bool
fn eq(&self, other: &InstanceHealthReason) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd for InstanceHealthReason
impl PartialOrd for InstanceHealthReason
source§fn partial_cmp(&self, other: &InstanceHealthReason) -> Option<Ordering>
fn partial_cmp(&self, other: &InstanceHealthReason) -> Option<Ordering>
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self
and other
) and is used by the <=
operator. Read moreimpl Eq for InstanceHealthReason
impl StructuralPartialEq for InstanceHealthReason
Auto Trait Implementations§
impl Freeze for InstanceHealthReason
impl RefUnwindSafe for InstanceHealthReason
impl Send for InstanceHealthReason
impl Sync for InstanceHealthReason
impl Unpin for InstanceHealthReason
impl UnwindSafe for InstanceHealthReason
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<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