moby/libnetwork
Sebastiaan van Stijn 2cf230951f
add //go:build directives to prevent downgrading to go1.16 language
This repository is not yet a module (i.e., does not have a `go.mod`). This
is not problematic when building the code in GOPATH or "vendor" mode, but
when using the code as a module-dependency (in module-mode), different semantics
are applied since Go1.21, which switches Go _language versions_ on a per-module,
per-package, or even per-file base.

A condensed summary of that logic [is as follows][1]:

- For modules that have a go.mod containing a go version directive; that
  version is considered a minimum _required_ version (starting with the
  go1.19.13 and go1.20.8 patch releases: before those, it was only a
  recommendation).
- For dependencies that don't have a go.mod (not a module), go language
  version go1.16 is assumed.
- Likewise, for modules that have a go.mod, but the file does not have a
  go version directive, go language version go1.16 is assumed.
- If a go.work file is present, but does not have a go version directive,
  language version go1.17 is assumed.

When switching language versions, Go _downgrades_ the language version,
which means that language features (such as generics, and `any`) are not
available, and compilation fails. For example:

    # github.com/docker/cli/cli/context/store
    /go/pkg/mod/github.com/docker/cli@v25.0.0-beta.2+incompatible/cli/context/store/storeconfig.go:6:24: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
    /go/pkg/mod/github.com/docker/cli@v25.0.0-beta.2+incompatible/cli/context/store/store.go:74:12: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)

Note that these fallbacks are per-module, per-package, and can even be
per-file, so _(indirect) dependencies_ can still use modern language
features, as long as their respective go.mod has a version specified.

Unfortunately, these failures do not occur when building locally (using
vendor / GOPATH mode), but will affect consumers of the module.

Obviously, this situation is not ideal, and the ultimate solution is to
move to go modules (add a go.mod), but this comes with a non-insignificant
risk in other areas (due to our complex dependency tree).

We can revert to using go1.16 language features only, but this may be
limiting, and may still be problematic when (e.g.) matching signatures
of dependencies.

There is an escape hatch: adding a `//go:build` directive to files that
make use of go language features. From the [go toolchain docs][2]:

> The go line for each module sets the language version the compiler enforces
> when compiling packages in that module. The language version can be changed
> on a per-file basis by using a build constraint.
>
> For example, a module containing code that uses the Go 1.21 language version
> should have a `go.mod` file with a go line such as `go 1.21` or `go 1.21.3`.
> If a specific source file should be compiled only when using a newer Go
> toolchain, adding `//go:build go1.22` to that source file both ensures that
> only Go 1.22 and newer toolchains will compile the file and also changes
> the language version in that file to Go 1.22.

This patch adds `//go:build` directives to those files using recent additions
to the language. It's currently using go1.19 as version to match the version
in our "vendor.mod", but we can consider being more permissive ("any" requires
go1.18 or up), or more "optimistic" (force go1.21, which is the version we
currently use to build).

For completeness sake, note that any file _without_ a `//go:build` directive
will continue to use go1.16 language version when used as a module.

[1]: 58c28ba286/src/cmd/go/internal/gover/version.go (L9-L56)
[2]: https://go.dev/doc/toolchain

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2023-12-15 15:24:15 +01:00
..
bitmap libnetwork/bitmap: improve documentation 2023-07-05 16:10:32 -04:00
cluster Switch from x/net/context -> context 2018-04-24 14:57:04 -07:00
cmd libnetwork/diagnostic: use standard http.Handler 2023-12-06 11:19:59 -05:00
config add //go:build directives to prevent downgrading to go1.16 language 2023-12-15 15:24:15 +01:00
datastore libnetwork/internal/kvstore: prune unused method 2023-10-19 12:57:42 -04:00
diagnostic libnetwork/diagnostic: lock mutex in help handler 2023-12-06 11:20:47 -05:00
discoverapi libnetwork: drop DatastoreConfig discovery type 2023-01-27 11:47:43 -05:00
docs libnetwork/docs: fix broken link 2023-05-10 12:05:05 +02:00
driverapi libnet: Replace BadRequest with InvalidParameter 2023-08-17 16:45:04 +02:00
drivers add //go:build directives to prevent downgrading to go1.16 language 2023-12-15 15:24:15 +01:00
drvregistry libnetwork: notify another driver registerer 2023-08-29 10:32:18 -04:00
etchosts libnetwork/etchosts: format code with gofumpt 2023-06-29 00:31:48 +02:00
internal add //go:build directives to prevent downgrading to go1.16 language 2023-12-15 15:24:15 +01:00
ipam libnetwork/ipam: refactor prefix-overlap checks 2023-11-01 11:44:24 -04:00
ipamapi libnet: Fix error capitalization 2023-08-17 16:48:09 +02:00
ipams migrate to github.com/containerd/log v0.1.0 2023-10-11 17:52:23 +02:00
ipamutils libnetwork/ipamutils: format code with gofumpt 2023-06-29 00:31:49 +02:00
ipbits libnet/ipam: use netip types internally 2023-02-23 18:10:01 -05:00
iptables migrate to github.com/containerd/log v0.1.0 2023-10-11 17:52:23 +02:00
netlabel New host_ipv6 bridge option to SNAT IPv6 connections 2023-10-25 20:11:49 -04:00
netutils tests: Move libnetwork/testutils to internal/testutils/netnsutils 2023-07-26 21:06:36 +02:00
networkdb libnetwork/diagnostic: use standard http.Handler 2023-12-06 11:19:59 -05:00
ns migrate to github.com/containerd/log v0.1.0 2023-10-11 17:52:23 +02:00
options add //go:build directives to prevent downgrading to go1.16 language 2023-12-15 15:24:15 +01:00
osl migrate to github.com/containerd/log v0.1.0 2023-10-11 17:52:23 +02:00
portallocator migrate to github.com/containerd/log v0.1.0 2023-10-11 17:52:23 +02:00
portmapper migrate to github.com/containerd/log v0.1.0 2023-10-11 17:52:23 +02:00
resolvconf migrate to github.com/containerd/log v0.1.0 2023-10-11 17:52:23 +02:00
scope libnetwork: move datastore Scope consts to libnetwork/scope 2023-07-28 21:56:48 +02:00
support Fixup libnetwork lint errors 2021-06-01 23:48:32 +00:00
types libnet: Replace NoServiceError with UnavailableError 2023-08-17 16:46:53 +02:00
.dockerignore Added back dockerignore 2018-06-22 16:10:22 -07:00
.gitignore Added back dockerignore 2018-06-22 16:10:22 -07:00
agent.go libnetwork/diagnostic: use standard http.Handler 2023-12-06 11:19:59 -05:00
agent.pb.go update generated files 2023-05-29 03:28:35 +02:00
agent.proto fix protos and "go generate" commands 2023-05-29 03:28:35 +02:00
controller.go libnetwork/diagnostic: drop Init method 2023-12-04 15:13:17 -05:00
controller_linux.go migrate to github.com/containerd/log v0.1.0 2023-10-11 17:52:23 +02:00
controller_others.go libnetwork: implement Controller.setupOSLSandbox 2023-08-23 20:13:15 +02:00
default_gateway.go migrate to github.com/containerd/log v0.1.0 2023-10-11 17:52:23 +02:00
default_gateway_freebsd.go libnetwork: remove Network interface 2023-07-22 11:56:41 +02:00
default_gateway_linux.go libnetwork: remove Network interface 2023-07-22 11:56:41 +02:00
default_gateway_windows.go libnetwork: remove Network interface 2023-07-22 11:56:41 +02:00
drivers_freebsd.go libnetwork: fix some missing imports on macOS and FreeBSD 2023-08-29 16:55:44 +02:00
drivers_ipam.go libnet: un-plumb datastores from IPAM inits 2023-01-27 11:47:42 -05:00
drivers_linux.go libnet/drivers: stop passing config to drivers... 2023-07-06 12:57:00 -04:00
drivers_unsupported.go libnetwork: fix some missing imports on macOS and FreeBSD 2023-08-29 16:55:44 +02:00
drivers_windows.go libnet/drivers: stop passing config to drivers... 2023-07-06 12:57:00 -04:00
endpoint.go Merge pull request #46681 from corhere/libn/datastore-misc-cleanups 2023-11-09 11:31:30 -08:00
endpoint_cnt.go libnetwork/datastore: drop (KVObject).DataScope() 2023-10-19 12:38:39 -04:00
endpoint_info.go libnetwork: Endpoint.AddStaticRoute don't create StaticRoute if unused 2023-08-29 19:51:41 +02:00
endpoint_info_unix.go remove pre-go1.17 build-tags 2023-05-19 20:38:51 +02:00
endpoint_info_windows.go remove pre-go1.17 build-tags 2023-05-19 20:38:51 +02:00
endpoint_unix_test.go libnetwork: rename unix-only testfiles 2023-08-12 01:27:38 +02:00
error.go libnet: Replace BadRequest with InvalidParameter 2023-08-17 16:45:04 +02:00
errors_test.go libnet: Replace BadRequest with InvalidParameter 2023-08-17 16:45:04 +02:00
firewall_linux.go migrate to github.com/containerd/log v0.1.0 2023-10-11 17:52:23 +02:00
firewall_linux_test.go tests: Move libnetwork/testutils to internal/testutils/netnsutils 2023-07-26 21:06:36 +02:00
firewall_others.go libnetwork: arrangeUserFilterRule: don't return early 2023-07-21 20:08:58 +02:00
libnetwork_internal_test.go libnet: add OTEL tracing to the embedded DNS 2023-10-06 19:14:48 +02:00
libnetwork_linux_test.go Plumb context through info endpoint 2023-11-10 20:09:25 +00:00
libnetwork_unix_test.go remove pre-go1.17 build-tags 2023-05-19 20:38:51 +02:00
libnetwork_windows_test.go libnetwork: format code with gofumpt 2023-06-29 00:31:49 +02:00
network.go add //go:build directives to prevent downgrading to go1.16 language 2023-12-15 15:24:15 +01:00
network_unix.go libnetwork: remove Network interface 2023-07-22 11:56:41 +02:00
network_windows.go migrate to github.com/containerd/log v0.1.0 2023-10-11 17:52:23 +02:00
README.md libnetwork: update example in README.md 2023-05-10 12:01:06 +02:00
resolver.go migrate to github.com/containerd/log v0.1.0 2023-10-11 17:52:23 +02:00
resolver_test.go migrate to github.com/containerd/log v0.1.0 2023-10-11 17:52:23 +02:00
resolver_unix.go libn: fix resolver restore w/ chatty 'iptables -C' 2023-05-30 14:32:27 -04:00
resolver_unix_test.go libnetwork: move resolver tests that were skipped on Windows 2023-08-11 15:00:30 +02:00
resolver_windows.go remove pre-go1.17 build-tags 2023-05-19 20:38:51 +02:00
sandbox.go libnetwork: refactor isDistributedControl() 2023-10-17 17:59:19 -04:00
sandbox_dns_unix.go migrate to github.com/containerd/log v0.1.0 2023-10-11 17:52:23 +02:00
sandbox_dns_unix_test.go libnetwork: move TestDNSOptions to a non-windows file 2023-08-11 14:59:30 +02:00
sandbox_dns_windows.go libnetwork: move more osl.Sandbox related code to Linux-only files 2023-08-23 20:13:15 +02:00
sandbox_externalkey_unix.go migrate to github.com/containerd/log v0.1.0 2023-10-11 17:52:23 +02:00
sandbox_externalkey_unsupported.go remove pre-go1.17 build-tags 2023-05-19 20:38:51 +02:00
sandbox_linux.go migrate to github.com/containerd/log v0.1.0 2023-10-11 17:52:23 +02:00
sandbox_options.go libnetwork: move all SandboxOptions to a separate file 2023-08-18 13:12:25 +02:00
sandbox_store.go Fix missing import for "scope" package 2023-11-09 22:48:01 +00:00
sandbox_unix_test.go libnetwork: implement Controller.GetSandbox(containerID) 2023-08-21 15:06:26 +02:00
sandbox_unsupported.go libnetwork/osl: remove Sandbox and Info interfaces 2023-08-23 23:29:09 +02:00
service.go add //go:build directives to prevent downgrading to go1.16 language 2023-12-15 15:24:15 +01:00
service_common.go migrate to github.com/containerd/log v0.1.0 2023-10-11 17:52:23 +02:00
service_common_unix_test.go libnetwork: rename unix-only testfiles 2023-08-12 01:27:38 +02:00
service_linux.go libnetwork: use conntrack and --ctstate for all rules 2023-10-13 00:56:30 -06:00
service_unsupported.go remove pre-go1.17 build-tags 2023-05-19 20:38:51 +02:00
service_windows.go migrate to github.com/containerd/log v0.1.0 2023-10-11 17:52:23 +02:00
store.go Plumb context through info endpoint 2023-11-10 20:09:25 +00:00
store_linux_test.go libnetwork/datastore: remove Store.KVStore() 2023-07-25 22:42:17 +02:00
store_test.go libnetwork: don't access KVStore directly in tests 2023-07-25 22:21:03 +02:00

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.

package main

import (
	"fmt"
	"log"

	"github.com/docker/docker/libnetwork"
	"github.com/docker/docker/libnetwork/config"
	"github.com/docker/docker/libnetwork/netlabel"
	"github.com/docker/docker/libnetwork/options"
)

func main() {
	// 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("example.com"))
	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.Fatal("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())
}

Contributing

Want to hack on libnetwork? Docker's contributions guidelines apply.

Code and documentation copyright 2015 Docker, inc. Code released under the Apache 2.0 license. Docs released under Creative commons.