#[non_exhaustive]pub enum ExternalMetricsSource {
Datadog,
Dynatrace,
Instana,
Newrelic,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against ExternalMetricsSource
, 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 externalmetricssource = unimplemented!();
match externalmetricssource {
ExternalMetricsSource::Datadog => { /* ... */ },
ExternalMetricsSource::Dynatrace => { /* ... */ },
ExternalMetricsSource::Instana => { /* ... */ },
ExternalMetricsSource::Newrelic => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when externalmetricssource
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant ExternalMetricsSource::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
ExternalMetricsSource::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 ExternalMetricsSource::NewFeature
is defined.
Specifically, when externalmetricssource
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on ExternalMetricsSource::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
Datadog
Dynatrace
Instana
Newrelic
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 ExternalMetricsSource
impl ExternalMetricsSource
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 ExternalMetricsSource
impl AsRef<str> for ExternalMetricsSource
source§impl Clone for ExternalMetricsSource
impl Clone for ExternalMetricsSource
source§fn clone(&self) -> ExternalMetricsSource
fn clone(&self) -> ExternalMetricsSource
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for ExternalMetricsSource
impl Debug for ExternalMetricsSource
source§impl From<&str> for ExternalMetricsSource
impl From<&str> for ExternalMetricsSource
source§impl FromStr for ExternalMetricsSource
impl FromStr for ExternalMetricsSource
source§impl Hash for ExternalMetricsSource
impl Hash for ExternalMetricsSource
source§impl Ord for ExternalMetricsSource
impl Ord for ExternalMetricsSource
source§fn cmp(&self, other: &ExternalMetricsSource) -> Ordering
fn cmp(&self, other: &ExternalMetricsSource) -> 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 ExternalMetricsSource
impl PartialEq for ExternalMetricsSource
source§fn eq(&self, other: &ExternalMetricsSource) -> bool
fn eq(&self, other: &ExternalMetricsSource) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd for ExternalMetricsSource
impl PartialOrd for ExternalMetricsSource
source§fn partial_cmp(&self, other: &ExternalMetricsSource) -> Option<Ordering>
fn partial_cmp(&self, other: &ExternalMetricsSource) -> 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 ExternalMetricsSource
impl StructuralEq for ExternalMetricsSource
impl StructuralPartialEq for ExternalMetricsSource
Auto Trait Implementations§
impl RefUnwindSafe for ExternalMetricsSource
impl Send for ExternalMetricsSource
impl Sync for ExternalMetricsSource
impl Unpin for ExternalMetricsSource
impl UnwindSafe for ExternalMetricsSource
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
§impl<Q, K> Comparable<K> for Q
impl<Q, K> Comparable<K> for Q
§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.