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22801e071f
This moves the initialization of the pre-defined networks to where it's
used instead of in package init.
This reason for this change is having this be populated in `init()`
causes it to always consume cpu, and memory (4.3MB of memory), to
populate even if the package is unused (like for instnace, in a re-exec).
Here is a memory profile of docker/docker just after starting the daemon of the
top 10 largest memory consumers:
Before:
```
flat flat% sum% cum cum%
0 0% 0% 11.89MB 95.96% runtime.goexit
0 0% 0% 6.79MB 54.82% runtime.main
0 0% 0% 5.79MB 46.74% main.init
0 0% 0% 4.79MB 38.67% github.com/docker/docker/api/server/router/network.init
0 0% 0% 4.79MB 38.67% github.com/docker/libnetwork.init
0 0% 0% 4.29MB 34.63% github.com/docker/libnetwork/ipam.init
0 0% 0% 4.29MB 34.63% github.com/docker/libnetwork/ipams/builtin.init
0 0% 0% 4.29MB 34.63% github.com/docker/libnetwork/ipamutils.init
0 0% 0% 4.29MB 34.63% github.com/docker/libnetwork/ipamutils.init.1
4.29MB 34.63% 34.63% 4.29MB 34.63% github.com/docker/libnetwork/ipamutils.initGranularPredefinedNetworks
```
After:
```
flat flat% sum% cum cum%
0 0% 0% 4439.37kB 89.66% runtime.goexit
0 0% 0% 4439.37kB 89.66% runtime.main
0 0% 0% 3882.11kB 78.40% github.com/docker/docker/cli.(*Cli).Run
0 0% 0% 3882.11kB 78.40% main.main
3882.11kB 78.40% 78.40% 3882.11kB 78.40% reflect.callMethod
0 0% 78.40% 3882.11kB 78.40% reflect.methodValueCall
0 0% 78.40% 557.26kB 11.25% github.com/docker/docker/api/server.init
557.26kB 11.25% 89.66% 557.26kB 11.25% html.init
0 0% 89.66% 557.26kB 11.25% html/template.init
0 0% 89.66% 557.26kB 11.25% main.init
```
Now, of course the docker daemon will still need to consume this memory, but
at least now re-execs and such won't have to re-init these variables.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
77 lines
2.1 KiB
Go
77 lines
2.1 KiB
Go
// Package ipamutils provides utililty functions for ipam management
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package ipamutils
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import (
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"fmt"
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"net"
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"github.com/docker/libnetwork/netutils"
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"github.com/docker/libnetwork/osl"
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"github.com/docker/libnetwork/resolvconf"
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"github.com/vishvananda/netlink"
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)
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// ElectInterfaceAddresses looks for an interface on the OS with the specified name
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// and returns its IPv4 and IPv6 addresses in CIDR form. If the interface does not exist,
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// it chooses from a predifined list the first IPv4 address which does not conflict
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// with other interfaces on the system.
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func ElectInterfaceAddresses(name string) (*net.IPNet, []*net.IPNet, error) {
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var (
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v4Net *net.IPNet
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v6Nets []*net.IPNet
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err error
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)
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InitNetworks()
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defer osl.InitOSContext()()
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link, _ := netlink.LinkByName(name)
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if link != nil {
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v4addr, err := netlink.AddrList(link, netlink.FAMILY_V4)
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if err != nil {
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return nil, nil, err
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}
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v6addr, err := netlink.AddrList(link, netlink.FAMILY_V6)
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if err != nil {
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return nil, nil, err
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}
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if len(v4addr) > 0 {
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v4Net = v4addr[0].IPNet
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}
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for _, nlAddr := range v6addr {
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v6Nets = append(v6Nets, nlAddr.IPNet)
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}
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}
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if link == nil || v4Net == nil {
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// Choose from predifined broad networks
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v4Net, err = FindAvailableNetwork(PredefinedBroadNetworks)
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if err != nil {
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return nil, nil, err
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}
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}
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return v4Net, v6Nets, nil
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}
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// FindAvailableNetwork returns a network from the passed list which does not
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// overlap with existing interfaces in the system
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func FindAvailableNetwork(list []*net.IPNet) (*net.IPNet, error) {
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// We don't check for an error here, because we don't really care if we
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// can't read /etc/resolv.conf. So instead we skip the append if resolvConf
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// is nil. It either doesn't exist, or we can't read it for some reason.
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var nameservers []string
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if rc, err := resolvconf.Get(); err == nil {
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nameservers = resolvconf.GetNameserversAsCIDR(rc.Content)
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}
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for _, nw := range list {
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if err := netutils.CheckNameserverOverlaps(nameservers, nw); err == nil {
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if err := netutils.CheckRouteOverlaps(nw); err == nil {
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return nw, nil
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}
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}
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}
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return nil, fmt.Errorf("no available network")
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}
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