Akihiro Suda 6b65b0c982 new driver: kubernetes
Tested with `kind` and GKE.

Note: "nodes" shown in `docker buildx ls` are unrelated to Kubernetes "nodes".
Probably buildx should come up with an alternative term.

Usage:

  $ kind create cluster
  $ export KUBECONFIG="$(kind get kubeconfig-path --name="kind")"

  $ docker buildx create --driver kubernetes --driver-opt replicas=3 --use
  $ docker buildx build -t foo --load .

`--load` loads the image into the local Docker.

Driver opts:

  - `image=IMAGE` - Sets the container image to be used for running buildkit.
  - `namespace=NS` - Sets the Kubernetes namespace. Defaults to the current namespace.
  - `replicas=N` - Sets the number of `Pod` replicas. Defaults to 1.
  - `rootless=(true|false)` - Run the container as a non-root user without `securityContext.privileged`. Defaults to false.
  - `loadbalance=(sticky|random)` - Load-balancing strategy. If set to "sticky", the pod is chosen using the hash of the context path. Defaults to "sticky"

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
2019-11-21 10:30:39 +09:00

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Go

// Copyright 2014 Google Inc. All rights reserved.
// Use of this source code is governed by the Apache 2.0
// license that can be found in the LICENSE file.
package internal
// This file implements a network dialer that limits the number of concurrent connections.
// It is only used for API calls.
import (
"log"
"net"
"runtime"
"sync"
"time"
)
var limitSem = make(chan int, 100) // TODO(dsymonds): Use environment variable.
func limitRelease() {
// non-blocking
select {
case <-limitSem:
default:
// This should not normally happen.
log.Print("appengine: unbalanced limitSem release!")
}
}
func limitDial(network, addr string) (net.Conn, error) {
limitSem <- 1
// Dial with a timeout in case the API host is MIA.
// The connection should normally be very fast.
conn, err := net.DialTimeout(network, addr, 500*time.Millisecond)
if err != nil {
limitRelease()
return nil, err
}
lc := &limitConn{Conn: conn}
runtime.SetFinalizer(lc, (*limitConn).Close) // shouldn't usually be required
return lc, nil
}
type limitConn struct {
close sync.Once
net.Conn
}
func (lc *limitConn) Close() error {
defer lc.close.Do(func() {
limitRelease()
runtime.SetFinalizer(lc, nil)
})
return lc.Conn.Close()
}