Function builder 

pub fn builder() -> Traceon

Returns a builder that can be configured before being turned on, or used as a layer for a subscriber.

use traceon::{Case, JoinFields, LevelFormat, SecondsFormat, SpanFormat, TimeFormat, TimeZone, info};
traceon::builder()
    // Add field with source code filename and line number e.g. src/main.rs:10
    .file()
    // Add field with target and module path e.g. mybinary::mymodule::submodule
    .module()
    // Turn off field with joined span name where the event occured e.g. parentspan::childspan
    .span(SpanFormat::None)
    // If the time is recorded in local system timezone or UTC
    .timezone(TimeZone::UTC)
    // Change the formatting of the time to RFC3339 with Seconds and Zulu
    .time(TimeFormat::RFC3339Options(SecondsFormat::Secs, true))
    // Change the casing of all the key names e.g. `camelCase` to `snake_case`
    .case(Case::Snake)
    // The characters used to concatenate field values that repeat in nested spans. Defaults to overwrite.
    .join_fields(JoinFields::All("::"))
    // Turn on json formatting instead of pretty output
    .json()
    // Change level value formatting to numbers for easier filtering
    // trace: 10
    // debug: 20
    // info:  30
    // warn:  40
    // error: 50
    .level(LevelFormat::Number)
    // Put anything that implements Write here to redirect output
    .writer(std::io::stderr())
    // This will activate it globally on all threads!
    .on();

info!("a simple message");

json output:

{
    "timestamp": "2023-01-01T12:58:49Z",
    "level": 30,
    "module": "builder",
    "file": "examples/builder.rs:32",
    "message": "a simple message"
}