Conditional debug logging for Go libraries.
View the docs.
$ go get github.com/tj/go-debug
package main
import . "github.com/tj/go-debug"
import "time"
var debug = Debug("single")
func main() {
for {
debug("sending mail")
debug("send email to %s", "[email protected]")
debug("send email to %s", "[email protected]")
debug("send email to %s", "[email protected]")
time.Sleep(500 * time.Millisecond)
}
}If you run the program with the DEBUG=* environment variable you will see:
15:58:15.115 34us 33us single - sending mail
15:58:15.116 3us 3us single - send email to [email protected]
15:58:15.116 1us 1us single - send email to [email protected]
15:58:15.116 1us 1us single - send email to [email protected]
15:58:15.620 504ms 504ms single - sending mail
15:58:15.620 6us 6us single - send email to [email protected]
15:58:15.620 4us 4us single - send email to [email protected]
15:58:15.620 4us 4us single - send email to [email protected]
15:58:16.123 503ms 503ms single - sending mail
15:58:16.123 7us 7us single - send email to [email protected]
15:58:16.123 4us 4us single - send email to [email protected]
15:58:16.123 4us 4us single - send email to [email protected]
15:58:16.625 501ms 501ms single - sending mail
15:58:16.625 4us 4us single - send email to [email protected]
15:58:16.625 4us 4us single - send email to [email protected]
15:58:16.625 5us 5us single - send email to [email protected]
A timestamp and two deltas are displayed. The timestamp consists of hour, minute, second and microseconds. The left-most delta is relative to the previous debug call of any name, followed by a delta specific to that debug function. These may be useful to identify timing issues and potential bottlenecks.
Executables often support --verbose flags for conditional logging, however
libraries typically either require altering your code to enable logging,
or simply omit logging all together. go-debug allows conditional logging
to be enabled via the DEBUG environment variable, where one or more
patterns may be specified.
For example suppose your application has several models and you want
to output logs for users only, you might use DEBUG=models:user. In contrast
if you wanted to see what all database activity was you might use DEBUG=models:*,
or if you're love being swamped with logs: DEBUG=*. You may also specify a list of names delimited by a comma, for example DEBUG=mongo,redis:*.
The name given should be the package name, however you can use whatever you like.
MIT