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99 lines
2.6 KiB
99 lines
2.6 KiB
package main
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import (
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"fmt"
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"log"
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"net/http"
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"net/http/httputil"
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"net/url"
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"os"
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)
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type AutoRegistry struct {
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host string
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port string
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backendRegistryUrl string
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reverseProxy *httputil.ReverseProxy
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}
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func NewAutoRegistry(host, port, backendRegistryUrl string) *AutoRegistry {
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proxy := AutoRegistry{
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host: host, port: port,
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backendRegistryUrl: backendRegistryUrl,
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}
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url, err := url.Parse(backendRegistryUrl)
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if err != nil {
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panic(err)
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}
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proxy.reverseProxy = httputil.NewSingleHostReverseProxy(url)
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return &proxy
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}
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func (autoProxy *AutoRegistry) setupHandler() {
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http.HandleFunc("/", autoProxy.requestHandler())
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}
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// ProxyRequestHandler handles the http request using proxy
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func (autoProxy *AutoRegistry) requestHandler() func(http.ResponseWriter, *http.Request) {
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return func(w http.ResponseWriter, r *http.Request) {
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autoProxy.pushImageIfNeeded(r, autoProxy.host+":"+autoProxy.port)
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autoProxy.reverseProxy.ServeHTTP(w, r)
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}
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}
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func (autoProxy *AutoRegistry) pushImageIfNeeded(r *http.Request, registry string) {
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// below will catch error but can return old image to the user.
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// This will lead to a lot of troubleshooting. Better is to fail the request to the client
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// when there is a problem with docker.
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//defer func() {
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// if r := recover(); r != nil {
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// log.Println("ERROR: Docker interaction failed: ", r)
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// }
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//}()
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log.Printf("Got request: %s, url: %s\n", r.Method, r.URL.Path)
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if r.Method != "HEAD" && r.Method != "GET" {
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return
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}
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image_name, tag_name, ok := ParseImage(r.URL.Path)
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if !ok {
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// not a manifest request
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return
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}
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docker_id, push_tag := GetDockerImageId(registry, image_name, tag_name)
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log.Printf("Docker id %s\n", docker_id)
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if docker_id == "" {
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return
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}
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registry_id := GetRegistryId(autoProxy.backendRegistryUrl, image_name, tag_name)
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if docker_id == registry_id {
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log.Printf("Image %s:%s is up to date in registry\n", image_name, tag_name)
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}
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log.Printf("image %s:%s is not up to date in registry, pushing it\n", image_name, tag_name)
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PushDockerImage(push_tag)
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}
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func printHelp() {
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fmt.Println("Usage: proxy <host> <port> <backendUrl>")
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}
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func main() {
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// make sure we can connect to docker and fail immediately otherwise
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CheckDockerAvailable()
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if len(os.Args) != 4 {
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printHelp()
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}
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host := os.Args[1]
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port := os.Args[2]
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backendRegistry := os.Args[3]
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log.Printf("Running with: host %s port %s backend %s\n", host, port, backendRegistry)
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proxy := NewAutoRegistry(host, port, backendRegistry)
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proxy.setupHandler()
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// handle all requests to your server using the proxy
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log.Fatal(http.ListenAndServe(":"+port, nil))
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}
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