Crate logged_stream 

logged-stream provides a single wrapper type, LoggedStream, that wraps any underlying IO object and logs every read, write, error, shutdown and drop that passes through it. The wrapper re-implements the same IO trait it wraps — Read / Write, or the tokio asynchronous analogues AsyncRead / AsyncWrite — so it is a drop-in replacement for the stream it decorates and works transparently in both synchronous and asynchronous code.

Architecture

LoggedStream is generic over four independent, pluggable parts. Each logged event flows through them in order: event -> Formatter -> Filter -> Logger.

• The inner IO object (S). The stream you are wrapping. LoggedStream implements the same IO trait S does, so it slots in wherever S was used.
• Formatter (BufferFormatter). Turns the read and written byte buffers into the display strings you see in the log.
• Filter (RecordFilter). Decides which records are logged. It runs on every record kind, including shutdown and drop.
• Logger (Logger). The sink that consumes accepted records.

All three of BufferFormatter, RecordFilter and Logger are public, Send + 'static and object-safe, with blanket implementations for Box<...> (and Arc<T> where T: Sync for BufferFormatter). You are free to supply your own implementation of any part.

Provided implementations

Formatters (BufferFormatter)

Control how byte buffers are rendered. Each formatter stores a separator (default :) and exposes parallel constructors: new, new_static, new_owned and new_default.

Formatter	Renders each byte as
LowercaseHexadecimalFormatter	lowercase hexadecimal — 0a:ff
UppercaseHexadecimalFormatter	uppercase hexadecimal — 0A:FF
DecimalFormatter	decimal — 10:255
OctalFormatter	octal — 012:377
BinaryFormatter	binary — 00001010:11111111

Filters (RecordFilter)

Decide which records reach the logger.

Filter	Behavior
DefaultFilter	Accepts every record.
RecordKindFilter	Accepts only the record kinds in an allow-list given at construction.
AllFilter	AND — a record passes only if every child filter accepts it (an empty list accepts everything).
AnyFilter	OR — a record passes if any child filter accepts it (an empty list rejects everything).

Loggers (Logger)

Consume each accepted record.

Logger	Destination
ConsoleLogger	Emits records through the log facade.
FileLogger	Writes records to a file.
MemoryStorageLogger	Retains recent records in a bounded in-memory buffer.
ChannelLogger	Sends records over an mpsc channel for handling elsewhere.

Structs

AllFilter

Implementation of RecordFilter that combines multiple filters with AND logic.

AnyFilter

Implementation of RecordFilter that combines multiple filters with OR logic.

BinaryFormatter

This implementation of BufferFormatter trait formats provided bytes buffer in binary number system.

ChannelLogger

Logger implementation that sends log records via an asynchronous channel.

ConsoleLogger

Logger implementation that writes log records to the console.

DecimalFormatter

This implementation of BufferFormatter trait formats provided bytes buffer in decimal number system.

DefaultFilter

This is default implementation of RecordFilter trait which check method always return true. It should be constructed using Default::default method.

FileLogger

This implementation of Logger trait writes log records (Record) into provided file.

LoggedStream

Wrapper for an IO object that logs every read, write, error, shutdown and drop that passes through it.

LowercaseHexadecimalFormatter

This implementation of BufferFormatter trait formats provided bytes buffer in hexadecimal number system.

MemoryStorageLogger

Logger implementation that writes log records to an inner VecDeque collection.

OctalFormatter

This implementation of BufferFormatter trait formats provided bytes buffer in octal number system.

Record

This structure represents a log record and contains message string, creation timestamp (DateTime<Utc>) and record kind (RecordKind).

RecordKindFilter

Implementation of RecordFilter that accepts allowed RecordKind array.

UppercaseHexadecimalFormatter

This implementation of BufferFormatter trait formats provided bytes buffer in hexadecimal number system.

Enums

RecordKind

This enumeration represents log record kind. It is contained inside Record and helps to determine how to work with log record message content which is different for each log record kind.

Traits

BufferFormatter

This trait allows to format bytes buffer using format_buffer method. It should be implemented for structures which are going to be used as formatting part inside LoggedStream.

Logger

Trait for processing log records in LoggedStream.

RecordFilter

Trait for filtering log records in LoggedStream.