0.4.1
A structured logging module for Deno
Repository
Current version released
4 years ago
Dependencies
std
Deno Structured Logging (currently unstable)
A better logger for deno, with support for structured logging.
Simple Example
import { createLogger, consoleSink } from "https://deno.land/x/deno_structured_logging@0.4.1/mod.ts";
const logger = createLogger().addSink(consoleSink());
logger.debug("Debug");
logger.info("Info");
logger.warn("Warn");
logger.error("Error");
logger.critical("Critical");
More complex example
import { green } from "https://deno.land/std@0.51.0/fmt/colors.ts";
import {
createLogger,
LogLevel,
consoleSink,
fileSink,
jsonFormat,
textFormat,
} from "https://deno.land/x/deno_structured_logging@0.4.1/mod.ts";
const logger = createLogger({
minimumLevel: LogLevel.INFO,
outputFormat: textFormat, // You can customise the default output format
})
.addSink(consoleSink({
colorOptions: { info: green } // You can customise the log level colors
}))
.addSink(fileSink("log.ndjson"), jsonFormat); // You can set a custom format per sink
logger.debug("Debug"); // Ignored due to the minimumLevel
logger.info("This is {type} logging in {program}", "Structured", "Deno");
// It doesn't matter what these variables are called,
const num = 1;
const array = ["a", "b", "c"];
logger.warn("Numbers work: {number} as well as arrays: {arr}", num, array);
String formatting
DSL uses it’s own form of string formatting, similar to Serilog in C#. The syntax for this is
logger.info("Hello {name}, this is another {variable}", "First", 2);
where "First"
and 2
are substituted into {name}
and {variable}
respectively. With the default console sink, the names don’t really matter however they help readability of the format and with more complex formats, for example a JSON format, they could be used as property names.
Available sinks
A sink is an output for DSL. For example the console sink prints to the console, or the file sink writes to a file. At this point a sink is literally just a function, so it’s easy enough to create your own.
Available sinks:
- Console Sink (with colors)
- File Sink
- More coming soon