A zerolog-inspired log library for Zig.
- Blazing fast
- Zero allocations
- Leveled logging
- Contextual logging
- JSON, Plain, and Pretty logging formats
Copy zlog folder to a libs subdirectory of the root of your project.
Then in your build.zig add:
const std = @import("std");
const zlog = @import("libs/zlog/build.zig");
pub fn build(b: *std.build.Builder) void {
...
exe.addPackage(zlog.pkg);
}Now you can import and use zlog!
For simple logging, import a global logger
const zlog = @import("zlog");
const log = &zlog.json_logger;
// You could also use pretty_logger, plain_logger
pub fn main() anyerror!void {
try log.print("Hello!");
}
// Output: {"time":1516134303,"level":"debug","message":"hello world"}Note: By default, log writes to StdErr at the log level of
.debugThe default log level global filter depends on the build mode:
- .Debug => .debug
- .ReleaseSafe => .info
- .ReleaseFast, .ReleaseSmall => .warn
Loggers create events, which do the log writing.
You can add strongly-typed key:value pairs to an event context.
Then the msg, msgf, or send method will write the event to the log.
Note: Without calling any of those 3 methods, the log will not be written.
const zlog = @import("zlog");
const log = &zlog.json_logger;
pub fn main() anyerror!void {
var ev = try log.event(.debug);
try ev.str("Scale", "833 cents");
try ev.num("Interval", 833.09);
try ev.msg("Fibonacci is everywhere");
var ev2 = try log.event(.debug);
try ev2.str("Name", "Tom");
try ev2.send();
}
// Output: {"time":1649450646,"level":"debug","Scale":"833 cents","Interval":833.09,"message":"Fibonacci is everywhere"}
// Output: {"time":1649450646,"level":"debug","Name":"Tom"}You can add context to a logger so that every event it creates also has that context. You can also create subloggers that use the parent logger's context along with their own context.
const zlog = @import("zlog");
const log = &zlog.json_logger;
pub fn main() anyerror!void {
try log.strCtx("component", "foo");
var ev = try log.event(.info);
try ev.msg("hello world");
// create sublogger, bringing along log's context
var sublog = try log.sublogger(.info);
try sublog.numCtx("num", 10);
var ev2 = try sublog.event(.debug);
try ev2.msg("hey there");
}
// Output: {"time":1649450791,"level":"info","component":"foo","message":"hello world"}
// Output: {"time":1649450791,"level":"debug","component":"foo","num":10,"message":"hey there"}zlog allow for logging at the following levels (from highest to lowest):
- panic
- fatal
- error
- warn
- info
- debug
- trace
A comptime-known level will be passed into log.event(LEVEL) or log.sublogger(LEVEL)
for leveled logging.
To disable logging entirely, set the global log level filter to .off;
const std = @import("std");
const zlog = @import("zlog");
// setting global log configuration
const log_conf = zlog.LogConfig{
.min_log_lvl = .trace, // lowest shown log level
.time_fmt = .unix_secs, // format to print the time
.buf_size = 1000, // buffer size for events, 1000 is the default
};
// creating a log manager with the set config
const log_man = zlog.LogManager(log_conf);
// choosing a default writer to write logs into
const log_writer = std.io.getStdErr().writer();
// choosing a default log level for the logger
const default_log_lvl = .info;
// Creating the logger
var log = log_man.Logger(@TypeOf(log_writer), .json, default_log_lvl)
.new(log_writer) catch @panic("Failed to create global JSON logger");
pub fn main() anyerror!void {
var ev = try log.event(.debug);
try ev.str("Scale", "833 cents");
try ev.num("Interval", 833.09);
try ev.msg("Fibonacci is everywhere");
var ev2 = try log.event(.debug);
try ev2.str("Name", "Tom");
try ev2.send();
}
// Output: {"time":1649450953,"level":"debug","Scale":"833 cents","Interval":833.09,"message":"Fibonacci is everywhere"}
// Output: {"time":1649450953,"level":"debug","Name":"Tom"}