Book Image

Go Systems Programming

Book Image

Go Systems Programming

Overview of this book

Go is the new systems programming language for Linux and Unix systems. It is also the language in which some of the most prominent cloud-level systems have been written, such as Docker. Where C programmers used to rule, Go programmers are in demand to write highly optimized systems programming code. Created by some of the original designers of C and Unix, Go expands the systems programmers toolkit and adds a mature, clear programming language. Traditional system applications become easier to write since pointers are not relevant and garbage collection has taken away the most problematic area for low-level systems code: memory management. This book opens up the world of high-performance Unix system applications to the beginning Go programmer. It does not get stuck on single systems or even system types, but tries to expand the original teachings from Unix system level programming to all types of servers, the cloud, and the web.
Table of Contents (13 chapters)

Rotating log files

Log files tend to get bigger and bigger all the time because data is written to them all the time; it would be good to have a technique for rotating them. This section will present such a technique. The name of the Go program will be rotateLog.go, and it will be presented in three parts. Note that for a process to rotate a log file, the process must be the one that opened that log file for writing. Trying to rotate a log that you do not own might create problems on your Unix machine, and should be avoided!

What you will also see here is another technique where you use your own log file for storing your log entries, with the help of log.SetOutput(): after a successful call to log.SetOutput(), each function call to log.Print() will make the output go to the log file used as the parameter of log.SetOutput().

The first part of rotateLog.go is the following:

package...