Struct SimpleCloudWatch 

pub struct SimpleCloudWatch { /* private fields */ }

Standard implementation of the CloudWatch service using the AWS SDK.

Design Considerations

AWS SDK for Rust is natively asynchronous. This implementation wraps the asynchronous client and manages an internal Tokio [Runtime][tokio::runtime::Runtime] to provide a synchronous (blocking) API.

Performance Note

Initializing this struct has a high overhead due to the creation of a multi-threaded Tokio [Runtime][tokio::runtime::Runtime]. It is recommended to initialize this service once and reuse the instance throughout the application’s lifecycle.

Alternatives

If high-performance logging is required without the overhead of an internal runtime, consider:

• Logging to stdout and using the CloudWatch Agent.
• Logging to stdout with a CloudWatchCout service and using the CloudWatch Agent.
• Using AWS Lambda integrated logging.

Implementations

impl SimpleCloudWatch

pub fn new(config: Config) -> Box<dyn CloudWatch + Send + Sync>

Initializes a new SimpleCloudWatch service using the StandardMessageFormatter.

This is a convenience wrapper around Self::new_formatted. It creates a multi-threaded Tokio runtime to manage the asynchronous AWS SDK synchronously under the hood.

Arguments

• config - A Config object containing AWS credentials and log group.

Panics

Panics if the Tokio [Runtime][tokio::runtime::Runtime] fails to initialize or the AWS region is invalid.

Example

let config = Config::new("access_key", "secret", "my-group", "us-east-1");
let service = SimpleCloudWatch::new(config);

pub fn new_formatted<F>( config: Config, formatter: F, ) -> Box<dyn CloudWatch + Send + Sync>

where F: MessageFormatter + Send + Sync + 'static,

Initializes a new SimpleCloudWatch service with a custom MessageFormatter.

Use this method if you need to customize how logs are structured (e.g., adding extra fields, changing JSON keys, or using a non-JSON format).

Arguments

• config - AWS configuration and credentials.
• formatter - An implementation of MessageFormatter.

Type Parameters

• F - The specific type of the formatter, which must be Send + Sync + 'static.

pub fn from_env(log_group: String) -> Box<dyn CloudWatch + Send + Sync>

Initializes the service using AWS standard environment variables.

It looks for AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, and AWS_REGION.

Arguments

• log_group - The name of the CloudWatch Log Group to use.

Panics

Panics if the internal Tokio [Runtime][tokio::runtime::Runtime] fails to initialize.

Example

// Assumes AWS_REGION and credentials are set in the environment
let cw_service = SimpleCloudWatch::from_env("my-app-logs".to_string());

pub fn from_env_formatted<F>( log_group: String, formatter: F, ) -> Box<dyn CloudWatch + Send + Sync>

where F: MessageFormatter + Send + Sync + 'static,

pub fn log_group(&self) -> &str

Returns the configured Log Group name.

pub fn get_data(&self) -> Arc<Data>

Returns the internal data

Trait Implementations

impl CloudWatch for SimpleCloudWatch

fn status(&self) -> Status

Checks if the service is operational.

This performs a synchronous check against AWS to verify:

1. Connectivity and Credentials.
2. Existence of the target Log Group.

fn work(&self, receiver: Receiver<CloudWatchMessage>)

This method runs in a dedicated thread and implements a greedy-drain /// batching strategy to optimize network I/O:

1. Idle Efficiency: It uses a blocking receiver.recv() to wait for the first message, ensuring the thread consumes zero CPU cycles when there is no logging activity.
2. Batch Formation: Once the first message is received, it performs non-blocking try_recv() calls to “drain” all currently pending messages in the channel into a single batch.
3. Synchronous Bridge: It utilizes the internal Tokio [Runtime][tokio::runtime::Runtime] via block_on to execute the asynchronous AWS SDK PutLogEvents call synchronously within the worker thread.

Thread Safety

This loop is designed to run indefinitely until the receiver is disconnected (usually when the application starts its shutdown sequence).

impl Fallback for SimpleCloudWatch

fn fallback(&self, _error: &ServiceError, msg: &Message)

Handles a message that could not be delivered to the primary service.