Enum aws_sdk_emr::model::ScaleDownBehavior

#[non_exhaustive]
pub enum ScaleDownBehavior {
    TerminateAtInstanceHour,
    TerminateAtTaskCompletion,
    Unknown(UnknownVariantValue),
}

When writing a match expression against ScaleDownBehavior, 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 scaledownbehavior = unimplemented!();
match scaledownbehavior {
    ScaleDownBehavior::TerminateAtInstanceHour => { /* ... */ },
    ScaleDownBehavior::TerminateAtTaskCompletion => { /* ... */ },
    other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
    _ => { /* ... */ },
}

The above code demonstrates that when scaledownbehavior represents NewFeature, the execution path will lead to the second last match arm, even though the enum does not contain a variant ScaleDownBehavior::NewFeature in the current version of SDK. The reason is that the variable other, created by the @ operator, is bound to ScaleDownBehavior::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 ScaleDownBehavior::NewFeature is defined. Specifically, when scaledownbehavior represents NewFeature, the execution path will hit the second last match arm as before by virtue of calling as_str on ScaleDownBehavior::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)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

TerminateAtInstanceHour

TerminateAtTaskCompletion

Unknown(UnknownVariantValue)

Unknown contains new variants that have been added since this code was generated.

Implementations

impl ScaleDownBehavior

pub fn as_str(&self) -> &str

Returns the &str value of the enum member.

Examples found in repository

src/model.rs (line 1266)

    fn as_ref(&self) -> &str {
        self.as_str()
    }

src/json_ser.rs (line 962)

pub fn serialize_structure_crate_input_run_job_flow_input(
    object: &mut aws_smithy_json::serialize::JsonObjectWriter,
    input: &crate::input::RunJobFlowInput,
) -> Result<(), aws_smithy_http::operation::error::SerializationError> {
    if let Some(var_154) = &input.name {
        object.key("Name").string(var_154.as_str());
    }
    if let Some(var_155) = &input.log_uri {
        object.key("LogUri").string(var_155.as_str());
    }
    if let Some(var_156) = &input.log_encryption_kms_key_id {
        object.key("LogEncryptionKmsKeyId").string(var_156.as_str());
    }
    if let Some(var_157) = &input.additional_info {
        object.key("AdditionalInfo").string(var_157.as_str());
    }
    if let Some(var_158) = &input.ami_version {
        object.key("AmiVersion").string(var_158.as_str());
    }
    if let Some(var_159) = &input.release_label {
        object.key("ReleaseLabel").string(var_159.as_str());
    }
    if let Some(var_160) = &input.instances {
        #[allow(unused_mut)]
        let mut object_161 = object.key("Instances").start_object();
        crate::json_ser::serialize_structure_crate_model_job_flow_instances_config(
            &mut object_161,
            var_160,
        )?;
        object_161.finish();
    }
    if let Some(var_162) = &input.steps {
        let mut array_163 = object.key("Steps").start_array();
        for item_164 in var_162 {
            {
                #[allow(unused_mut)]
                let mut object_165 = array_163.value().start_object();
                crate::json_ser::serialize_structure_crate_model_step_config(
                    &mut object_165,
                    item_164,
                )?;
                object_165.finish();
            }
        }
        array_163.finish();
    }
    if let Some(var_166) = &input.bootstrap_actions {
        let mut array_167 = object.key("BootstrapActions").start_array();
        for item_168 in var_166 {
            {
                #[allow(unused_mut)]
                let mut object_169 = array_167.value().start_object();
                crate::json_ser::serialize_structure_crate_model_bootstrap_action_config(
                    &mut object_169,
                    item_168,
                )?;
                object_169.finish();
            }
        }
        array_167.finish();
    }
    if let Some(var_170) = &input.supported_products {
        let mut array_171 = object.key("SupportedProducts").start_array();
        for item_172 in var_170 {
            {
                array_171.value().string(item_172.as_str());
            }
        }
        array_171.finish();
    }
    if let Some(var_173) = &input.new_supported_products {
        let mut array_174 = object.key("NewSupportedProducts").start_array();
        for item_175 in var_173 {
            {
                #[allow(unused_mut)]
                let mut object_176 = array_174.value().start_object();
                crate::json_ser::serialize_structure_crate_model_supported_product_config(
                    &mut object_176,
                    item_175,
                )?;
                object_176.finish();
            }
        }
        array_174.finish();
    }
    if let Some(var_177) = &input.applications {
        let mut array_178 = object.key("Applications").start_array();
        for item_179 in var_177 {
            {
                #[allow(unused_mut)]
                let mut object_180 = array_178.value().start_object();
                crate::json_ser::serialize_structure_crate_model_application(
                    &mut object_180,
                    item_179,
                )?;
                object_180.finish();
            }
        }
        array_178.finish();
    }
    if let Some(var_181) = &input.configurations {
        let mut array_182 = object.key("Configurations").start_array();
        for item_183 in var_181 {
            {
                #[allow(unused_mut)]
                let mut object_184 = array_182.value().start_object();
                crate::json_ser::serialize_structure_crate_model_configuration(
                    &mut object_184,
                    item_183,
                )?;
                object_184.finish();
            }
        }
        array_182.finish();
    }
    if input.visible_to_all_users {
        object
            .key("VisibleToAllUsers")
            .boolean(input.visible_to_all_users);
    }
    if let Some(var_185) = &input.job_flow_role {
        object.key("JobFlowRole").string(var_185.as_str());
    }
    if let Some(var_186) = &input.service_role {
        object.key("ServiceRole").string(var_186.as_str());
    }
    if let Some(var_187) = &input.tags {
        let mut array_188 = object.key("Tags").start_array();
        for item_189 in var_187 {
            {
                #[allow(unused_mut)]
                let mut object_190 = array_188.value().start_object();
                crate::json_ser::serialize_structure_crate_model_tag(&mut object_190, item_189)?;
                object_190.finish();
            }
        }
        array_188.finish();
    }
    if let Some(var_191) = &input.security_configuration {
        object.key("SecurityConfiguration").string(var_191.as_str());
    }
    if let Some(var_192) = &input.auto_scaling_role {
        object.key("AutoScalingRole").string(var_192.as_str());
    }
    if let Some(var_193) = &input.scale_down_behavior {
        object.key("ScaleDownBehavior").string(var_193.as_str());
    }
    if let Some(var_194) = &input.custom_ami_id {
        object.key("CustomAmiId").string(var_194.as_str());
    }
    if let Some(var_195) = &input.ebs_root_volume_size {
        object.key("EbsRootVolumeSize").number(
            #[allow(clippy::useless_conversion)]
            aws_smithy_types::Number::NegInt((*var_195).into()),
        );
    }
    if let Some(var_196) = &input.repo_upgrade_on_boot {
        object.key("RepoUpgradeOnBoot").string(var_196.as_str());
    }
    if let Some(var_197) = &input.kerberos_attributes {
        #[allow(unused_mut)]
        let mut object_198 = object.key("KerberosAttributes").start_object();
        crate::json_ser::serialize_structure_crate_model_kerberos_attributes(
            &mut object_198,
            var_197,
        )?;
        object_198.finish();
    }
    if let Some(var_199) = &input.step_concurrency_level {
        object.key("StepConcurrencyLevel").number(
            #[allow(clippy::useless_conversion)]
            aws_smithy_types::Number::NegInt((*var_199).into()),
        );
    }
    if let Some(var_200) = &input.managed_scaling_policy {
        #[allow(unused_mut)]
        let mut object_201 = object.key("ManagedScalingPolicy").start_object();
        crate::json_ser::serialize_structure_crate_model_managed_scaling_policy(
            &mut object_201,
            var_200,
        )?;
        object_201.finish();
    }
    if let Some(var_202) = &input.placement_group_configs {
        let mut array_203 = object.key("PlacementGroupConfigs").start_array();
        for item_204 in var_202 {
            {
                #[allow(unused_mut)]
                let mut object_205 = array_203.value().start_object();
                crate::json_ser::serialize_structure_crate_model_placement_group_config(
                    &mut object_205,
                    item_204,
                )?;
                object_205.finish();
            }
        }
        array_203.finish();
    }
    if let Some(var_206) = &input.auto_termination_policy {
        #[allow(unused_mut)]
        let mut object_207 = object.key("AutoTerminationPolicy").start_object();
        crate::json_ser::serialize_structure_crate_model_auto_termination_policy(
            &mut object_207,
            var_206,
        )?;
        object_207.finish();
    }
    if let Some(var_208) = &input.os_release_label {
        object.key("OSReleaseLabel").string(var_208.as_str());
    }
    Ok(())
}

pub const fn values() -> &'static [&'static str]

Returns all the &str values of the enum members.

Trait Implementations

impl AsRef<str> for ScaleDownBehavior

fn as_ref(&self) -> &str

Converts this type into a shared reference of the (usually inferred) input type.

impl Clone for ScaleDownBehavior

fn clone(&self) -> ScaleDownBehavior

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ScaleDownBehavior

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

Formats the value using the given formatter.

impl From<&str> for ScaleDownBehavior

fn from(s: &str) -> Self

Converts to this type from the input type.

impl FromStr for ScaleDownBehavior

type Err = Infallible

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 Hash for ScaleDownBehavior

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)where
    H: Hasher,
    Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for ScaleDownBehavior

fn cmp(&self, other: &ScaleDownBehavior) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Selfwhere
    Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Selfwhere
    Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Selfwhere
    Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval.

impl PartialEq<ScaleDownBehavior> for ScaleDownBehavior

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

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

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

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd<ScaleDownBehavior> for ScaleDownBehavior

fn partial_cmp(&self, other: &ScaleDownBehavior) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Eq for ScaleDownBehavior

impl StructuralEq for ScaleDownBehavior

impl StructuralPartialEq for ScaleDownBehavior