Enum nakadion::components::committer::CommitStrategy

pub enum CommitStrategy {
    Immediately,
    LatestPossible,
    After {
        seconds: Option<u32>,
        cursors: Option<u32>,
        events: Option<u32>,
    },
}

Defines how to commit cursors

This value should always be set when creating a Consumer because otherwise a it will be guessed by Nakadion which might not result in best performance.

FromStr

use nakadion::components::committer::CommitStrategy;

let strategy = "immediately".parse::<CommitStrategy>().unwrap();
assert_eq!(strategy, CommitStrategy::Immediately);

let strategy = "latest_possible".parse::<CommitStrategy>().unwrap();
assert_eq!(strategy, CommitStrategy::LatestPossible);

let strategy = "after seconds:1 cursors:2 events:3".parse::<CommitStrategy>().unwrap();
assert_eq!(
    strategy,
    CommitStrategy::After {
        seconds: Some(1),
        cursors: Some(2),
        events: Some(3),
    }
);

let strategy = "after seconds:1 events:3".parse::<CommitStrategy>().unwrap();
assert_eq!(
    strategy,
    CommitStrategy::After {
        seconds: Some(1),
        cursors: None,
        events: Some(3),
    }
);

assert!("after".parse::<CommitStrategy>().is_err());

JSON is also valid:

use nakadion::components::committer::CommitStrategy;

let strategy = r#""immediately""#.parse::<CommitStrategy>().unwrap();
assert_eq!(strategy, CommitStrategy::Immediately);

let strategy = r#""latest_possible""#.parse::<CommitStrategy>().unwrap();
assert_eq!(strategy, CommitStrategy::LatestPossible);

let strategy = r#"{"after":{"seconds":1, "cursors":3}}"#.parse::<CommitStrategy>().unwrap();
assert_eq!(
    strategy,
    CommitStrategy::After {
        seconds: Some(1),
        cursors: Some(3),
        events: None,
    }
);

Environment variables

Fetching values from the environment uses FromStr for parsing

Variants

Immediately

Commit cursors immediately

LatestPossible

Commit cursors as late as possible.

This strategy is determined by the commit timeout defined via StreamParameters

After

Commit after on of the criteria was met:

• seconds: After seconds seconds. If not set, it will be 10 seconds.
• cursors: After cursors cursors have been received
• events: After events have been received. This requires the BatchHandler to give a hint on the amount of events processed.

Fields of After

seconds: Option<u32>cursors: Option<u32>events: Option<u32>

Implementations

impl CommitStrategy

pub const ENV_TYPE_NAME: &'static str

The default name of the environment variable for this type. The name of the environment variable is “ COMMIT_STRATEGY “

pub fn try_from_env() -> Result<Option<Self>, Error>

Initialize from the environment. Returns None if the value was not found and fails if the value could not be parsed. The name of the environment variable is “NAKADION_ COMMIT_STRATEGY “

pub fn try_from_env_prefixed<T: Into<String>>(
    prefix: T
) -> Result<Option<Self>, Error>

Initialize from the environment. Returns None if the value was not found and fails if the value could not be parsed. The name of the environment variable is “prefix_ COMMIT_STRATEGY “ The underscore and prefix will be omitted if prefix is empty.

pub fn try_from_env_named<T: AsRef<str>>(
    var_name: T
) -> Result<Option<Self>, Error>

Initialize from the environment. Returns None if the value was not found and fails if the value could not be parsed. The name of the environment variable is var_name.

pub fn try_from_env_type_name() -> Result<Option<Self>, Error>

Initialize from the environment. Returns None if the value was not found and fails if the value could not be parsed. The name of the environment variable is “ COMMIT_STRATEGY “

pub fn from_env() -> Result<Self, Error>

Initialize from the environment. Fails if the value was not found or if the value could not be parsed. The name of the environment variable is “NAKADION_ COMMIT_STRATEGY “

pub fn from_env_prefixed<T: Into<String>>(prefix: T) -> Result<Self, Error>

Initialize from the environment. Fails if the value was not found or if the value could not be parsed. The name of the environment variable is “prefix_ COMMIT_STRATEGY “ The underscore and prefix will be omitted if prefix is empty.

pub fn from_env_named<T: AsRef<str>>(var_name: T) -> Result<Self, Error>

Initialize from the environment. Fails if the value was not found or if the value could not be parsed. The name of the environment variable is var_name.

pub fn from_env_type_name() -> Result<Self, Error>

Initialize from the environment. Fails if the value was not found or if the value could not be parsed. The name of the environment variable is “ COMMIT_STRATEGY “

pub fn from_env_opt() -> Option<Self>

Initialize from the environment. Returns None if the value could not be read for any reason. The name of the environment variable is “NAKADION_ COMMIT_STRATEGY “

pub fn from_env_opt_prefixed<T: Into<String>>(prefix: T) -> Option<Self>

Initialize from the environment. Returns None if the value could not be read for any reason. The name of the environment variable is “prefix_ COMMIT_STRATEGY “ The underscore and prefix will be omitted if prefix is empty.

pub fn from_env_opt_named<T: AsRef<str>>(var_name: T) -> Option<Self>

Initialize from the environment. Returns None if the value could not be read for any reason. The name of the environment variable is var_name.

pub fn from_env_opt_type_name() -> Option<Self>

Initialize from the environment. Returns None if the value could not be read for any reason. The name of the environment variable is “ COMMIT_STRATEGY “

pub fn after_seconds(seconds: u32) -> Self

pub fn validate(&self) -> Result<(), Error>

pub fn derive_from_stream_parameters(
    stream_parameters: &StreamParameters
) -> Self

pub fn commit_after_secs_interval(&self) -> Option<u32>

Returns the seconds after which to always commit.

If CommitStrategy::Immediately is activated, Some(0) will be returned. If CommitStrategy::After is activated with seconds = None, Some(10) will be returned. If CommitStrategy::LatestPossible is activated, None will be returned.

Trait Implementations

impl Clone for CommitStrategy

fn clone(&self) -> CommitStrategy

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for CommitStrategy

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

Formats the value using the given formatter.

impl Default for CommitStrategy

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for CommitStrategy

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error> where
    __D: Deserializer<'de>, 

Deserialize this value from the given Serde deserializer.

impl Display for CommitStrategy

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

Formats the value using the given formatter.

impl FromStr for CommitStrategy

type Err = Error

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type.

impl PartialEq<CommitStrategy> for CommitStrategy

fn eq(&self, other: &CommitStrategy) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &CommitStrategy) -> bool

This method tests for !=.

impl Serialize for CommitStrategy

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error> where
    __S: Serializer, 

Serialize this value into the given Serde serializer.

impl Copy for CommitStrategy

impl Eq for CommitStrategy

impl StructuralEq for CommitStrategy

impl StructuralPartialEq for CommitStrategy