moby--moby/vendor/github.com/RackSec/srslog

srslog

Go has a syslog package in the standard library, but it has the following shortcomings:

1. It doesn't have TLS support
2. According to bradfitz on the Go team, it is no longer being maintained.

I agree that it doesn't need to be in the standard library. So, I've followed Brad's suggestion and have made a separate project to handle syslog.

This code was taken directly from the Go project as a base to start from.

However, this does have TLS support.

Usage

Basic usage retains the same interface as the original syslog package. We only added to the interface where required to support new functionality.

Switch from the standard library:

import(
    //"log/syslog"
    syslog "github.com/RackSec/srslog"
)

You can still use it for local syslog:

w, err := syslog.Dial("", "", syslog.LOG_ERR, "testtag")

Or to unencrypted UDP:

w, err := syslog.Dial("udp", "192.168.0.50:514", syslog.LOG_ERR, "testtag")

Or to unencrypted TCP:

w, err := syslog.Dial("tcp", "192.168.0.51:514", syslog.LOG_ERR, "testtag")

But now you can also send messages via TLS-encrypted TCP:

w, err := syslog.DialWithTLSCertPath("tcp+tls", "192.168.0.52:514", syslog.LOG_ERR, "testtag", "/path/to/servercert.pem")

And if you need more control over your TLS configuration :

pool := x509.NewCertPool()
serverCert, err := ioutil.ReadFile("/path/to/servercert.pem")
if err != nil {
    return nil, err
}
pool.AppendCertsFromPEM(serverCert)
config := tls.Config{
    RootCAs: pool,
}

w, err := DialWithTLSConfig(network, raddr, priority, tag, &config)

(Note that in both TLS cases, this uses a self-signed certificate, where the remote syslog server has the keypair and the client has only the public key.)

And then to write log messages, continue like so:

if err != nil {
    log.Fatal("failed to connect to syslog:", err)
}
defer w.Close()

w.Alert("this is an alert")
w.Crit("this is critical")
w.Err("this is an error")
w.Warning("this is a warning")
w.Notice("this is a notice")
w.Info("this is info")
w.Debug("this is debug")
w.Write([]byte("these are some bytes"))

If you need further control over connection attempts, you can use the DialWithCustomDialer function. To continue with the DialWithTLSConfig example:

netDialer := &net.Dialer{Timeout: time.Second*5} // easy timeouts
realNetwork := "tcp" // real network, other vars your dail func can close over
dial := func(network, addr string) (net.Conn, error) {
    // cannot use "network" here as it'll simply be "custom" which will fail
    return tls.DialWithDialer(netDialer, realNetwork, addr, &config)
}

w, err := DialWithCustomDialer("custom", "192.168.0.52:514", syslog.LOG_ERR, "testtag", dial)

Your custom dial func can set timeouts, proxy connections, and do whatever else it needs before returning a net.Conn.

Generating TLS Certificates

We've provided a script that you can use to generate a self-signed keypair:

pip install cryptography
python script/gen-certs.py

That outputs the public key and private key to standard out. Put those into .pem files. (And don't put them into any source control. The certificate in the test directory is used by the unit tests, and please do not actually use it anywhere else.)

Running Tests

Run the tests as usual:

go test

But we've also provided a test coverage script that will show you which lines of code are not covered:

script/coverage --html

That will open a new browser tab showing coverage information.

License

This project uses the New BSD License, the same as the Go project itself.

Code of Conduct

Please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms.