The previous code used string slices to limit the length of certain
fields like endpoint or sandbox IDs. This assumes that these strings
are at least as long as the slice length. Unfortunately, some sandbox
IDs can be smaller than 7 characters. This fix addresses this issue
by systematically converting format string calls that were taking
fixed-slice arguments to use a precision specifier in the string format
itself. From the golang fmt package documentation:
For strings, byte slices and byte arrays, however, precision limits
the length of the input to be formatted (not the size of the output),
truncating if necessary. Normally it is measured in runes, but for
these types when formatted with the %x or %X format it is measured
in bytes.
This nicely fits the desired behavior: it will limit the number of
runes considered for string interpolation to the precision value.
Signed-off-by: Chris Telfer <ctelfer@docker.com>
libnetwork - networking for containers
Libnetwork provides a native Go implementation for connecting containers
The goal of libnetwork is to deliver a robust Container Network Model that provides a consistent programming interface and the required network abstractions for applications.
Design
Please refer to the design for more information.
Using libnetwork
There are many networking solutions available to suit a broad range of use-cases. libnetwork uses a driver / plugin model to support all of these solutions while abstracting the complexity of the driver implementations by exposing a simple and consistent Network Model to users.
func main() {
if reexec.Init() {
return
}
// Select and configure the network driver
networkType := "bridge"
// Create a new controller instance
driverOptions := options.Generic{}
genericOption := make(map[string]interface{})
genericOption[netlabel.GenericData] = driverOptions
controller, err := libnetwork.New(config.OptionDriverConfig(networkType, genericOption))
if err != nil {
log.Fatalf("libnetwork.New: %s", err)
}
// Create a network for containers to join.
// NewNetwork accepts Variadic optional arguments that libnetwork and Drivers can use.
network, err := controller.NewNetwork(networkType, "network1", "")
if err != nil {
log.Fatalf("controller.NewNetwork: %s", err)
}
// For each new container: allocate IP and interfaces. The returned network
// settings will be used for container infos (inspect and such), as well as
// iptables rules for port publishing. This info is contained or accessible
// from the returned endpoint.
ep, err := network.CreateEndpoint("Endpoint1")
if err != nil {
log.Fatalf("network.CreateEndpoint: %s", err)
}
// Create the sandbox for the container.
// NewSandbox accepts Variadic optional arguments which libnetwork can use.
sbx, err := controller.NewSandbox("container1",
libnetwork.OptionHostname("test"),
libnetwork.OptionDomainname("docker.io"))
if err != nil {
log.Fatalf("controller.NewSandbox: %s", err)
}
// A sandbox can join the endpoint via the join api.
err = ep.Join(sbx)
if err != nil {
log.Fatalf("ep.Join: %s", err)
}
// libnetwork client can check the endpoint's operational data via the Info() API
epInfo, err := ep.DriverInfo()
if err != nil {
log.Fatalf("ep.DriverInfo: %s", err)
}
macAddress, ok := epInfo[netlabel.MacAddress]
if !ok {
log.Fatalf("failed to get mac address from endpoint info")
}
fmt.Printf("Joined endpoint %s (%s) to sandbox %s (%s)\n", ep.Name(), macAddress, sbx.ContainerID(), sbx.Key())
}
Future
Please refer to roadmap for more information.
Contributing
Want to hack on libnetwork? Docker's contributions guidelines apply.
Copyright and license
Code and documentation copyright 2015 Docker, inc. Code released under the Apache 2.0 license. Docs released under Creative commons.