Struct tracing_subscriber::fmt::format::Format

pub struct Format<F = Full, T = SystemTime> { /* private fields */ }

A pre-configured event formatter.

You will usually want to use this as the FormatEvent for a FmtSubscriber.

The default logging format, Full includes all fields in each event and its containing spans. The Compact logging format includes only the fields from the most-recently-entered span.

Implementations

impl<T> Format<Pretty, T>

pub fn with_source_location(self, display_location: bool) -> Self

Sets whether or not the source code location from which an event originated is displayed.

This defaults to true.

impl<F, T> Format<F, T>

pub fn compact(self) -> Format<Compact, T>

Use a less verbose output format.

See Compact.

pub fn pretty(self) -> Format<Pretty, T>

Use an excessively pretty, human-readable output format.

See Pretty.

Note that this requires the “ansi” feature to be enabled.

Options

Format::with_ansi can be used to disable ANSI terminal escape codes (which enable formatting such as colors, bold, italic, etc) in event formatting. However, a field formatter must be manually provided to avoid ANSI in the formatting of parent spans, like so:

tracing_subscriber::fmt()
   .pretty()
   .with_ansi(false)
   .fmt_fields(format::PrettyFields::new().with_ansi(false))
   // ... other settings ...
   .init();

pub fn json(self) -> Format<Json, T>

Use the full JSON format.

The full format includes fields from all entered spans.

Example Output

{"timestamp":"Feb 20 11:28:15.096","level":"INFO","target":"mycrate","fields":{"message":"some message", "key": "value"}}

Options

• Format::flatten_event can be used to enable flattening event fields into the root object.

pub fn with_timer<T2>(self, timer: T2) -> Format<F, T2>

Use the given timer for log message timestamps.

See time module for the provided timer implementations.

Note that using the chrono feature flag enables the additional time formatters ChronoUtc and ChronoLocal.

pub fn without_time(self) -> Format<F, ()>

Do not emit timestamps with log messages.

pub fn with_ansi(self, ansi: bool) -> Format<F, T>

Enable ANSI terminal colors for formatted output.

pub fn with_target(self, display_target: bool) -> Format<F, T>

Sets whether or not an event’s target is displayed.

pub fn with_level(self, display_level: bool) -> Format<F, T>

Sets whether or not an event’s level is displayed.

pub fn with_thread_ids(self, display_thread_id: bool) -> Format<F, T>

Sets whether or not the thread ID of the current thread is displayed when formatting events

pub fn with_thread_names(self, display_thread_name: bool) -> Format<F, T>

Sets whether or not the name of the current thread is displayed when formatting events

impl<T> Format<Json, T>

pub fn flatten_event(self, flatten_event: bool) -> Format<Json, T>

Use the full JSON format with the event’s event fields flattened.

Example Output

{"timestamp":"Feb 20 11:28:15.096","level":"INFO","target":"mycrate", "message":"some message", "key": "value"}

See Json.

pub fn with_current_span(self, display_current_span: bool) -> Format<Json, T>

Sets whether or not the formatter will include the current span in formatted events.

See format::Json

pub fn with_span_list(self, display_span_list: bool) -> Format<Json, T>

Sets whether or not the formatter will include a list (from root to leaf) of all currently entered spans in formatted events.

See format::Json

Trait Implementations

impl<F: Clone, T: Clone> Clone for Format<F, T>

fn clone(&self) -> Format<F, T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<F: Debug, T: Debug> Debug for Format<F, T>

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

Formats the value using the given formatter.

impl Default for Format<Full, SystemTime>

fn default() -> Self

Returns the “default value” for a type.

impl<C, N, T> FormatEvent<C, N> for Format<Pretty, T>where
    C: Subscriber + for<'a> LookupSpan<'a>,
    N: for<'a> FormatFields<'a> + 'static,
    T: FormatTime,

fn format_event(
    &self,
    ctx: &FmtContext<'_, C, N>,
    writer: &mut dyn Write,
    event: &Event<'_>
) -> Result

Write a log message for Event in Context to the given Write.

impl<S, N, T> FormatEvent<S, N> for Format<Compact, T>where
    S: Subscriber + for<'a> LookupSpan<'a>,
    N: for<'a> FormatFields<'a> + 'static,
    T: FormatTime,

fn format_event(
    &self,
    ctx: &FmtContext<'_, S, N>,
    writer: &mut dyn Write,
    event: &Event<'_>
) -> Result

Write a log message for Event in Context to the given Write.

impl<S, N, T> FormatEvent<S, N> for Format<Full, T>where
    S: Subscriber + for<'a> LookupSpan<'a>,
    N: for<'a> FormatFields<'a> + 'static,
    T: FormatTime,

fn format_event(
    &self,
    ctx: &FmtContext<'_, S, N>,
    writer: &mut dyn Write,
    event: &Event<'_>
) -> Result

Write a log message for Event in Context to the given Write.

impl<S, N, T> FormatEvent<S, N> for Format<Json, T>where
    S: Subscriber + for<'lookup> LookupSpan<'lookup>,
    N: for<'writer> FormatFields<'writer> + 'static,
    T: FormatTime,

fn format_event(
    &self,
    ctx: &FmtContext<'_, S, N>,
    writer: &mut dyn Write,
    event: &Event<'_>
) -> Resultwhere
    S: Subscriber + for<'a> LookupSpan<'a>,

Write a log message for Event in Context to the given Write.