0.5.6

Key Changes

• Wrap the termcolor::Color API so it's no longer a public dependency

Contributions

• @KodrAus Wrap termcolor's color api

More Details

This patch fixes an issue that slipped through 0.5.0 where the termcolor::Color type was re-exported instead of redefined.

This is a potentially breaking change

Instead of re-exporting termcolor::Color, we now redefine the same API in env_logger. The potential breakage is if anyone was relying on the fact that env_logger::Color and termcolor::Color were equivalent types. This was only obvious from the source, and a survey of public code using env_logger and call for comment hasn't revealed any code relying on this.

0.5.5

Key Changes

• Allow toggling parts of the default format without having to write one from scratch

Contributions

• @KodrAus Allow toggling parts of the default format

More Details

Builder::default_format_*

The default format can be easily tweaked by conditionally enabling/disabling parts of it in the main Builder. The API looks like:

impl Builder {
    fn default_format(&mut self) -> &mut Self;
    fn default_format_timestamp(&mut self, write: bool) -> &mut Self;
    fn default_format_module_path(&mut self, write: bool) -> &mut Self;
    fn default_format_level(&mut self, write: bool) -> &mut Self;
}

Calling default_format_* will store whether or not we want to include those parts of the log, without affecting a custom format. That means:

Builder::new()
    .format(|buf, record| { ... })
    .default_format_timestamp(false)
    .init();

Is the same as:

Builder::new()
    .format(|buf, record| { ... })
    .init();

Setting a custom format won't clobber any values passed to default_format_* methods. That means:

Builder::new()
    .default_format_timestamp(false)
    .format(|buf, record| { ... })
    .default_format()
    .init();

Is the same as:

Builder::new()
    .default_format_timestamp(false)
    .init();

Builder::from_default_env

A new from_default_env method that's a convenient way of calling from_env(env_logger::Env::default()).

0.5.4

Key Changes

• Better panic message when attempting to initialise the global logger multiple times
• Use humantime instead of chrono for formatting timestamps

Changes to minimum Rust

The minimum version of Rust required has been set at 1.18.0. We may change this in patch versions, but will always flag it in the release notes here.

You can always check the .travis.yml file to see the current minimum supported version.

New Dependencies

• humantime for formatting timestamps. This replaces the dependency on chrono

Contributions

• @BurntSushi ci: add minimum Rust version
• @stepancheg Better error message when init called twice
• @tailhook Use humantime instead of chrono

0.5.3

Key Changes

• Support more intense variants of color using intensity. Call set_intense(true) to produce a lighter color, and set_intense(false) to produce the default color.

Contributions

• @quadrupleslap Added fmt::Style::set_intense

0.5.2

Key Changes

• Detect whether stdout/stderr is a tty and write styles accordingly. This fixes an issue with color control characters showing up logs piped to files

New Dependencies

• atty for interrogating stdout/stderr

Contributions

• @quadrupleslap Use atty to check for color support

0.5.1

Key Changes

• Fixed a panic in some rare logging cases and updated some incorrect sample code in the readme

Contributions

• @alexheretic update readme 'in tests' init usage
• @alexcrichton Avoid panicking for logging-while-logging

0.5.0

NOTE: These release notes are collected from the 0.5.0-rc.1 and 0.5.0-rc.2 release notes.

Key Changes

• Support for using custom environment variables to parse the log level filter and color output
• Added colors with configuration through an environment variable and an RFC3339-formatted timestamp to the default format
• Buffer log output so logs over multiple lines won't end up interleaved in multi-threaded applications
• Move the filter parsing into its own module so it's easier to consume in custom loggers
• Documentation!

Breaking Changes

• LogTarget has been renamed to Target
• LogBuilder has been renamed to Builder
• The Builder::format method now accepts a F: Fn(&mut Formatter, &Record) -> Result<()> + Sync + Send. This is the new formatting API that writes into a Formatter instead of producing an owned String
• Builder::init will panic if the logger can't be initialised. A new Builder::try_init method has been added with the same semantics as the old Builder::init method

New Dependencies

• chrono for the timestamp
• termcolor for record buffering and colors

Contributions

• @matthiasbeyer Dependencies: log: 0.4.0-rc.1 -> 0.4.0
• @KodrAus Public color API
• @rukai Fix spelling error
• @KodrAus Make the timestamp format more compact
• @mjkillough Allow custom timestamp formats.
• @KodrAus Add rfc3339 timestamps to default format
• @KodrAus Support colors and buffer writes
• @KodrAus Make filtering public
• @FuGangqiang fix doc and reformat code style
• @KodrAus Add examples for custom format and logger impls
• @sfackler Fix std feature name
• @jimmycuadra Adds a new constructor and init functions for custom env vars.
• @jimmycuadra Update to the latest commit of log / deny debug impls, missing docs, and warnings.
• @jethrogb Enable use of Logger as a filter

Thanks to everybody who helped make this release of env_logger happen!

More Details

Disabling colors

Adds a new builder property for whether or not to include colors. By default this is controlled by the RUST_LOG_STYLE environment variable, but it can be overridden.

Setting this environment variable to never will disable colors and other styles:

$ export RUST_LOG_STYLE=never
$ ./my-app

Valid values are:

• auto (or missing/invalid) will decide whether or not the terminal supports colors
• always will always use colors
• never will never use colors

In order to support multiple environment variables, I've refactored our from_env functions to accept a generic T: Into<Env>, where Env is a container for the environment variables we care about. These methods can now be called in a few ways:

// reads filters from `MY_LOG` and styles from `RUST_LOG_STYLE`
env_logger::init_from_env("MY_LOG");

// reads filters from `MY_LOG` and styles from `MY_LOG_STYLE`
env_logger::init_from_env(Env::default().filter("MY_LOG").write_style("MY_LOG_STYLE"));

This lets us add new environment variables in the future without potentially breaking people. But it does mean if you're overriding all environment variables that new ones could slip in without you noticing.

Using alternative environment variables

Since we use two environment variables to configure the logger we need an ergonomic way to pass different combinations of those variables to from_env methods. This PR adds an Env type with builder methods for naming environment variables:

env_logger::init_from_env(Env::new().filter("MY_LOG"));

With a few From conversions, the above is also equivalent to:

env_logger::init_from_env("MY_LOG");

Whether or not we want to keep these conversions is up for discussion.

Writing colors

The color API has been refactored and made public so you can use them in your own formats:

let mut style = buf.style();

style.set_color(Color::Red).set_bold(true).set_bg(Color::White);

writeln!(buf, "{}", style.value(42))

This saves you from having to split the writes into multiple calls and juggle Result types.

Writing timestamps

Call the timestamp method on a Formatter to get an opaque timestamp that can be logged. It'll be written in an RFC3339 format:

let ts = buf.timestamp();

writeline!(buf, "log at: {}", ts)

0.5.0-rc.2

Key Changes

• Make the color API public
• Tweak the log format to be more aligned

Contributions

• @matthiasbeyer Dependencies: log: 0.4.0-rc.1 -> 0.4.0
• @KodrAus Public color API
• @rukai Fix spelling error

More Details

Disabling colors

Adds a new builder property for whether or not to include colors. By default this is RUST_LOG_STYLE, but it can be overridden.

Setting this environment variable to never will disable colors and other styles:

$ export RUST_LOG_STYLE=never
$ ./my-app

Valid values are:

• auto (or missing/invalid) will decide whether or not the terminal supports colors
• always will always use colors
• never will never use colors

In order to support multiple environment variables, I've refactored our from_env functions to accept a generic T: Into<Env>, where Env is a container for the environment variables we care about. These methods can now be called in a few ways:

// reads filters from `MY_LOG` and styles from `RUST_LOG_STYLE`
env_logger::init_from_env("MY_LOG");

// reads filters from `MY_LOG` and styles from `MY_LOG_STYLE`
env_logger::init_from_env(Env::default().filter("MY_LOG").write_style("MY_LOG_STYLE"));

This lets us add new environment variables in the future without potentially breaking people. But it does mean if you're overriding all environment variables that new ones could slip in without you noticing.

Using alternative environment variables

Since we use two environment variables to configure the logger we need an ergonomic way to pass different combinations of those variables to from_env methods. This PR adds an Env type with builder methods for naming environment variables:

env_logger::init_from_env(Env::new().filter("MY_LOG"));

With a few From conversions, the above is also equivalent to:

env_logger::init_from_env("MY_LOG");

Whether or not we want to keep these conversions is up for discussion.

Writing colors

The color API has been refactored and made public so you can use them in your own formats:

let mut style = buf.style();

style.set_color(Color::Red).set_bold(true).set_bg(Color::White);

writeln!(buf, "{}", style.value(42))

This saves you from having to split the writes into multiple calls and juggle Result types.

Writing timestamps

Oh the Formatter.timestamp method is now also public so you can grab timestamps.

0.5.0-rc.1

Key changes

• Support for using custom environment variables to parse the log level filter
• Added colors and an RFC3339-formatted timestamp to the default format
• Buffer log output so logs over multiple lines won't end up interleaved in multi-threaded applications
• Move the filter parsing into its own module so it's easier to consume in custom loggers
• Documentation!

Breaking changes

• LogTarget has been renamed to Target
• LogBuilder has been renamed to Builder
• The Builder::format method now accepts a F: Fn(&mut Formatter, &Record) -> Result<()> + Sync + Send. This is the new formatting API that writes into a Formatter instead of producing an owned String
• Builder::init will panic if the logger can't be initialised. A new Builder::try_init method has been added with the same semantics as the old Builder::init method

Contributions

• @KodrAus Make the timestamp format more compact
• @mjkillough Allow custom timestamp formats.
• @KodrAus Add rfc3339 timestamps to default format
• @KodrAus Support colors and buffer writes
• @KodrAus Make filtering public
• @FuGangqiang fix doc and reformat code style
• @KodrAus Add examples for custom format and logger impls
• @sfackler Fix std feature name
• @jimmycuadra Adds a new constructor and init functions for custom env vars.
• @jimmycuadra Update to the latest commit of log / deny debug impls, missing docs, and warnings.
• @jethrogb Enable use of Logger as a filter

Thanks to everybody who helped make this release of env_logger happen!

New dependencies

• chrono for the timestamp
• termcolor for record buffering and colors