youtubebeat/vendor/github.com/elastic/beats/libbeat/common/docker/client.go

66 lines
2 KiB
Go

// Licensed to Elasticsearch B.V. under one or more contributor
// license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright
// ownership. Elasticsearch B.V. licenses this file to you under
// the Apache License, Version 2.0 (the "License"); you may
// not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
package docker
import (
"net/http"
"os"
"github.com/elastic/beats/libbeat/logp"
"github.com/docker/docker/api"
"github.com/docker/docker/api/types/versions"
"github.com/docker/docker/client"
"golang.org/x/net/context"
)
// NewClient builds and returns a new Docker client
// It uses version 1.30 by default, and negotiates it with the server so it is downgraded if 1.30 is too high
func NewClient(host string, httpClient *http.Client, httpHeaders map[string]string) (*client.Client, error) {
version := os.Getenv("DOCKER_API_VERSION")
if version == "" {
version = api.DefaultVersion
}
c, err := client.NewClient(host, version, httpClient, nil)
if err != nil {
return c, err
}
if os.Getenv("DOCKER_API_VERSION") == "" {
logp.Debug("docker", "Negotiating client version")
ping, err := c.Ping(context.Background())
if err != nil {
logp.Debug("docker", "Failed to perform ping: %s", err)
}
// try a really old version, before versioning headers existed
if ping.APIVersion == "" {
ping.APIVersion = "1.22"
}
// if server version is lower than the client version, downgrade
if versions.LessThan(ping.APIVersion, version) {
c.UpdateClientVersion(ping.APIVersion)
}
}
logp.Debug("docker", "Client version set to %s", c.ClientVersion())
return c, nil
}