pub struct Formatter { /* private fields */ }
Expand description

A formatter to write logs into.

Formatter implements the standard Write trait for writing log records. It also supports terminal colors, through the style method.

Examples

Use the writeln macro to format a log record. An instance of a Formatter is passed to an env_logger format as buf:

use std::io::Write;

let mut builder = env_logger::Builder::new();

builder.format(|buf, record| writeln!(buf, "{}: {}", record.level(), record.args()));

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impl Formatter

pub fn timestamp(&self) -> Timestamp

Get a Timestamp for the current date and time in UTC.

Examples

Include the current timestamp with the log record:

use std::io::Write;

let mut builder = env_logger::Builder::new();

builder.format(|buf, record| {
    let ts = buf.timestamp();

    writeln!(buf, "{}: {}: {}", ts, record.level(), record.args())
});

pub fn timestamp_seconds(&self) -> Timestamp

Get a Timestamp for the current date and time in UTC with full second precision.

pub fn timestamp_millis(&self) -> Timestamp

Get a Timestamp for the current date and time in UTC with millisecond precision.

pub fn timestamp_micros(&self) -> Timestamp

Get a Timestamp for the current date and time in UTC with microsecond precision.

pub fn timestamp_nanos(&self) -> Timestamp

Get a Timestamp for the current date and time in UTC with nanosecond precision.

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impl Formatter

pub fn style(&self) -> Style

Begin a new Style.

Examples

Create a bold, red colored style and use it to print the log level:

use std::io::Write;
use env_logger::fmt::Color;

let mut builder = env_logger::Builder::new();

builder.format(|buf, record| {
    let mut level_style = buf.style();

    level_style.set_color(Color::Red).set_bold(true);

    writeln!(buf, "{}: {}",
        level_style.value(record.level()),
        record.args())
});

pub fn default_level_style(&self, level: Level) -> Style

Get the default Style for the given level.

The style can be used to print other values besides the level.

pub fn default_styled_level(&self, level: Level) -> StyledValue<'static, Level>

Get a printable Style for the given level.

The style can only be used to print the level.

Trait Implementations§

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impl Debug for Formatter

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

Formats the value using the given formatter. Read more
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impl Write for Formatter

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fn write(&mut self, buf: &[u8]) -> Result<usize, Error>

Write a buffer into this writer, returning how many bytes were written. Read more
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fn flush(&mut self) -> Result<(), Error>

Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
1.36.0 · source§

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers. Read more
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fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)
Determines if this Writer has an efficient write_vectored implementation. Read more
1.0.0 · source§

fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer. Read more
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fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)
Attempts to write multiple buffers into this writer. Read more
1.0.0 · source§

fn write_fmt(&mut self, fmt: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered. Read more
1.0.0 · source§

fn by_ref(&mut self) -> &mut Selfwhere Self: Sized,

Creates a “by reference” adapter for this instance of Write. Read more

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impl<T> Any for Twhere 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 Twhere 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 Twhere 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> Downcast<T> for T

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fn downcast(&self) -> &T

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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<S> FromSample<S> for S

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fn from_sample_(s: S) -> S

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impl<T, U> Into<U> for Twhere 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<F, T> IntoSample<T> for Fwhere T: FromSample<F>,

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fn into_sample(self) -> T

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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<T, U> ToSample<U> for Twhere U: FromSample<T>,

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fn to_sample_(self) -> U

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impl<T, U> TryFrom<U> for Twhere 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 Twhere 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<T> Upcast<T> for T

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fn upcast(&self) -> Option<&T>

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impl<V, T> VZip<V> for Twhere V: MultiLane<T>,

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fn vzip(self) -> V

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impl<W> WriteBytesExt for Wwhere W: Write + ?Sized,

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fn write_u8(&mut self, n: u8) -> Result<(), Error>

Writes an unsigned 8 bit integer to the underlying writer. Read more
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fn write_i8(&mut self, n: i8) -> Result<(), Error>

Writes a signed 8 bit integer to the underlying writer. Read more
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fn write_u16<T>(&mut self, n: u16) -> Result<(), Error>where T: ByteOrder,

Writes an unsigned 16 bit integer to the underlying writer. Read more
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fn write_i16<T>(&mut self, n: i16) -> Result<(), Error>where T: ByteOrder,

Writes a signed 16 bit integer to the underlying writer. Read more
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fn write_u24<T>(&mut self, n: u32) -> Result<(), Error>where T: ByteOrder,

Writes an unsigned 24 bit integer to the underlying writer. Read more
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fn write_i24<T>(&mut self, n: i32) -> Result<(), Error>where T: ByteOrder,

Writes a signed 24 bit integer to the underlying writer. Read more
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fn write_u32<T>(&mut self, n: u32) -> Result<(), Error>where T: ByteOrder,

Writes an unsigned 32 bit integer to the underlying writer. Read more
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fn write_i32<T>(&mut self, n: i32) -> Result<(), Error>where T: ByteOrder,

Writes a signed 32 bit integer to the underlying writer. Read more
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fn write_u48<T>(&mut self, n: u64) -> Result<(), Error>where T: ByteOrder,

Writes an unsigned 48 bit integer to the underlying writer. Read more
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fn write_i48<T>(&mut self, n: i64) -> Result<(), Error>where T: ByteOrder,

Writes a signed 48 bit integer to the underlying writer. Read more
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fn write_u64<T>(&mut self, n: u64) -> Result<(), Error>where T: ByteOrder,

Writes an unsigned 64 bit integer to the underlying writer. Read more
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fn write_i64<T>(&mut self, n: i64) -> Result<(), Error>where T: ByteOrder,

Writes a signed 64 bit integer to the underlying writer. Read more
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fn write_u128<T>(&mut self, n: u128) -> Result<(), Error>where T: ByteOrder,

Writes an unsigned 128 bit integer to the underlying writer.
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fn write_i128<T>(&mut self, n: i128) -> Result<(), Error>where T: ByteOrder,

Writes a signed 128 bit integer to the underlying writer.
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fn write_uint<T>(&mut self, n: u64, nbytes: usize) -> Result<(), Error>where T: ByteOrder,

Writes an unsigned n-bytes integer to the underlying writer. Read more
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fn write_int<T>(&mut self, n: i64, nbytes: usize) -> Result<(), Error>where T: ByteOrder,

Writes a signed n-bytes integer to the underlying writer. Read more
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fn write_uint128<T>(&mut self, n: u128, nbytes: usize) -> Result<(), Error>where T: ByteOrder,

Writes an unsigned n-bytes integer to the underlying writer. Read more
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fn write_int128<T>(&mut self, n: i128, nbytes: usize) -> Result<(), Error>where T: ByteOrder,

Writes a signed n-bytes integer to the underlying writer. Read more
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fn write_f32<T>(&mut self, n: f32) -> Result<(), Error>where T: ByteOrder,

Writes a IEEE754 single-precision (4 bytes) floating point number to the underlying writer. Read more
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fn write_f64<T>(&mut self, n: f64) -> Result<(), Error>where T: ByteOrder,

Writes a IEEE754 double-precision (8 bytes) floating point number to the underlying writer. Read more
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impl<T> Any for Twhere T: Any,

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impl<S, T> Duplex<S> for Twhere T: FromSample<S> + ToSample<S>,