Struct mz_dyncfg::Config

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pub struct Config<D: ConfigDefault> { /* private fields */ }
Expand description

A handle to a dynamically updatable configuration value.

This represents a strongly-typed named config of type T. It may be registered to a set of such configs with ConfigSet::add and then later used to retrieve the latest value at any time with Self::get.

The supported types are bool, usize, Duration, and String, as well as Option variants of these as necessary.

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impl<D: ConfigDefault> Config<D>

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pub const fn new(name: &'static str, default: D, desc: &'static str) -> Self

Constructs a handle for a config of type T.

It is best practice, but not strictly required, for the name to be globally unique within a process.

TODO(cfg): Add some sort of categorization of config purpose here: e.g. limited-lifetime rollout flag, CYA, magic number that we never expect to tune, magic number that we DO expect to tune, etc. This could be used to power something like a --future-default-flags for CI, to replace part or all of the manually maintained list.

TODO(cfg): See if we can make this more Rust-y and take these params as a struct (the obvious thing hits some issues with const combined with Drop).

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pub fn name(&self) -> &str

The name of this config.

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pub fn desc(&self) -> &str

The description of this config.

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pub fn default(&self) -> &D

The default value of this config.

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pub fn get(&self, set: &ConfigSet) -> D::ConfigType

Returns the latest value of this config within the given set.

Panics if this config was not previously registered to the set.

TODO(cfg): Decide if this should be a method on ConfigSet instead to match the precedent of BTreeMap/HashMap::get taking a key. It’s like this initially because it was thought that the Config definition was the more important “noun” and also that rustfmt would maybe work better on this ordering.

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pub fn handle(&self, set: &ConfigSet) -> ConfigValHandle<D::ConfigType>

Returns a handle to the value of this config in the given set.

This allows users to amortize the cost of the name lookup.

Trait Implementations§

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impl<D: Clone + ConfigDefault> Clone for Config<D>

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fn clone(&self) -> Config<D>

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<D: Debug + ConfigDefault> Debug for Config<D>

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

Formats the value using the given formatter. Read more

Auto Trait Implementations§

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impl<D> RefUnwindSafe for Config<D>
where D: RefUnwindSafe,

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impl<D> Send for Config<D>
where D: Send,

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impl<D> Sync for Config<D>
where D: Sync,

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impl<D> Unpin for Config<D>
where D: Unpin,

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impl<D> UnwindSafe for Config<D>
where D: UnwindSafe,

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T, U> CastInto<U> for T
where U: CastFrom<T>,

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fn cast_into(self) -> U

Performs the cast.
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> FromRef<T> for T
where T: Clone,

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fn from_ref(input: &T) -> T

Converts to this type from a reference to the input type.
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impl<T> FutureExt for T

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fn with_context(self, otel_cx: Context) -> WithContext<Self>

Attaches the provided Context to this type, returning a WithContext wrapper. Read more
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fn with_current_context(self) -> WithContext<Self>

Attaches the current Context to this type, returning a WithContext wrapper. Read more
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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoRequest<T> for T

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fn into_request(self) -> Request<T>

Wrap the input message T in a tonic::Request
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impl<T> Pointable for T

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const ALIGN: usize = _

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<P, R> ProtoType<R> for P
where R: RustType<P>,

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impl<T> Same for T

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type Output = T

Should always be Self
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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V

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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more