Tag listing, fix potential deadlock if the response does not respect the page size.

cli/docker-ls/cmd_repositories.go

@@ -23,17 +23,13 @@ func (r *repositoriesCmd) execute(argv []string) (err error) {
 
 	registryApi := lib.NewRegistryApi(cfg)
 
-	listResult, err := registryApi.ListRepositories()
+	listResult := registryApi.ListRepositories()
 
-	if err != nil {
-		return
-	} else {
 	for repository := range listResult.Repositories() {
 		fmt.Println(repository.Name())
 	}
 
 	err = listResult.LastError()
-	}
 
 	return
 }

cli/docker-ls/cmd_tags.go

@@ -2,6 +2,10 @@ package main
 
 import (
 	"flag"
+	"fmt"
+	"os"
+
+	"git.mayflower.de/vaillant-team/docker-ls/lib"
 )
 
 type tagsCmd struct {
@@ -9,7 +13,31 @@ type tagsCmd struct {
 }
 
 func (r *tagsCmd) execute(argv []string) (err error) {
-	err = r.flags.Parse(argv)
+	cfg := lib.NewConfig()
+	cfg.BindToFlags(r.flags)
+
+	if len(argv) == 0 {
+		r.flags.Usage()
+		os.Exit(1)
+	}
+
+	repositoryName := argv[0]
+
+	err = r.flags.Parse(argv[1:])
+
+	if err != nil {
+		return
+	}
+
+	registryApi := lib.NewRegistryApi(cfg)
+
+	listResult := registryApi.ListTags(repositoryName)
+
+	for tag := range listResult.Tags() {
+		fmt.Println(tag.Name())
+	}
+
+	err = listResult.LastError()
 
 	return
 }

cli/docker-ls/usage.go

@@ -3,6 +3,7 @@ package main
 import (
 	"flag"
 	"fmt"
+	"strings"
 )
 
 const COMMAND_USAGE_TEMPLATE = `usage: docker-ls %s%s [options]
@@ -13,6 +14,10 @@ valid options:
 
 func commandUsage(command string, argstring string, flags *flag.FlagSet) func() {
 	return func() {
+		if argstring != "" {
+			argstring = " " + strings.TrimLeft(argstring, " ")
+		}
+
 		fmt.Printf(COMMAND_USAGE_TEMPLATE, command, argstring)
 		flags.PrintDefaults()
 	}

lib/api_errors.go

@@ -8,6 +8,7 @@ type AutorizationError string
 type NotImplementedByRemoteError string
 type MalformedResponseError string
 type InvalidStatusCodeError string
+type NotFoundError string
 
 var genericAuthorizationError AutorizationError = "autorization failed"
 var genericMalformedResponseError MalformedResponseError = "malformed response"
@@ -28,6 +29,14 @@ func (e InvalidStatusCodeError) Error() string {
 	return string(e)
 }
 
+func (e NotFoundError) Error() string {
+	return string(e)
+}
+
 func newInvalidStatusCodeError(code int) error {
 	return InvalidStatusCodeError(fmt.Sprintf("invalid API response status %d", code))
 }
+
+func newNotFoundError(description string) error {
+	return NotFoundError(description)
+}

lib/api_interface.go

@@ -9,6 +9,17 @@ type RepositoryListResponse interface {
 	LastError() error
 }
 
-type RegistryApi interface {
-	ListRepositories() (RepositoryListResponse, error)
+type Tag interface {
+	Name() string
+	RepositoryName() string
+}
+
+type TagListResponse interface {
+	Tags() <-chan Tag
+	LastError() error
+}
+
+type RegistryApi interface {
+	ListRepositories() RepositoryListResponse
+	ListTags(repositoryName string) TagListResponse
 }

lib/api_paginated_request.go

@@ -0,0 +1,108 @@
+package lib
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/url"
+)
+
+type validatable interface {
+	validate() error
+}
+
+type paginatedRequestResponse interface {
+	setLastError(error)
+	close()
+}
+
+type paginatedRequestContext interface {
+	path() string
+	validateApiResponse(response *http.Response, initialRequest bool) error
+	processPartialResponse(response paginatedRequestResponse, apiResponse interface{})
+	createResponse(api *registryApi) paginatedRequestResponse
+	createJsonResponse() validatable
+}
+
+func (r *registryApi) executePaginatedRequest(ctx paginatedRequestContext, url *url.URL, initialRequest bool) (response *http.Response, close bool, err error) {
+	response, err = r.connector.Get(url)
+
+	if err != nil {
+		return
+	}
+
+	if err == nil {
+		close = response.Close
+		err = ctx.validateApiResponse(response, initialRequest)
+	}
+
+	return
+}
+
+func (r *registryApi) iteratePaginatedRequest(
+	ctx paginatedRequestContext,
+	lastApiResponse *http.Response,
+	response paginatedRequestResponse,
+) (
+	apiResponse *http.Response,
+	more bool,
+	err error,
+) {
+	requestUrl, err := r.paginatedRequestEndpointUrl(ctx.path(), lastApiResponse)
+
+	if err != nil {
+		return
+	}
+
+	apiResponse, needsClose, err := r.executePaginatedRequest(ctx, requestUrl, lastApiResponse == nil)
+
+	if needsClose {
+		defer apiResponse.Body.Close()
+	}
+
+	if err != nil {
+		return
+	}
+
+	more = apiResponse.Header.Get("link") != ""
+
+	jsonResponse := ctx.createJsonResponse()
+	decoder := json.NewDecoder(apiResponse.Body)
+	err = decoder.Decode(&jsonResponse)
+
+	if err != nil {
+		return
+	}
+
+	err = jsonResponse.validate()
+
+	if err != nil {
+		return
+	}
+
+	ctx.processPartialResponse(response, jsonResponse)
+
+	return
+}
+
+func (r *registryApi) paginatedRequest(ctx paginatedRequestContext) (response paginatedRequestResponse) {
+	response = ctx.createResponse(r)
+
+	go func() {
+		var apiResponse *http.Response
+		var err error
+		more := true
+
+		for more {
+			apiResponse, more, err = r.iteratePaginatedRequest(ctx, apiResponse, response)
+
+			if err != nil {
+				response.setLastError(err)
+				break
+			}
+		}
+
+		response.close()
+	}()
+
+	return
+}

lib/api_repository_list.go

@@ -1,9 +1,7 @@
 package lib
 
 import (
-	"encoding/json"
 	"net/http"
-	"net/url"
 )
 
 type repositoryListResponse struct {
@@ -11,10 +9,6 @@ type repositoryListResponse struct {
 	err          error
 }
 
-type repositoryListJsonResponse struct {
-	Repositories *[]string `json:"repositories"`
-}
-
 func (r *repositoryListResponse) Repositories() <-chan Repository {
 	return (r.repositories)
 }
@@ -23,100 +17,68 @@ func (r *repositoryListResponse) LastError() error {
 	return r.err
 }
 
-func (r *registryApi) executeListRequest(url *url.URL, initialRequest bool) (response *http.Response, close bool, err error) {
-	response, err = r.connector.Get(url)
+func (r *repositoryListResponse) setLastError(err error) {
+	r.err = err
+}
 
-	if err != nil {
-		return
+func (r *repositoryListResponse) close() {
+	close(r.repositories)
+}
+
+type repositoryListJsonResponse struct {
+	Repositories []string `json:"repositories"`
+}
+
+func (r *repositoryListJsonResponse) validate() error {
+	if r.Repositories == nil {
+		return genericMalformedResponseError
 	}
 
-	close = response.Close
+	return nil
+}
 
+type repositoryListRequestContext struct{}
+
+func (r *repositoryListRequestContext) path() string {
+	return "v2/_catalog"
+}
+
+func (r *repositoryListRequestContext) validateApiResponse(response *http.Response, initialRequest bool) error {
 	switch response.StatusCode {
 	case http.StatusUnauthorized, http.StatusForbidden:
-		err = genericAuthorizationError
-		return
+		return genericAuthorizationError
 
 	case http.StatusNotFound:
 		if initialRequest {
-			err = NotImplementedByRemoteError("registry does not implement repository listings")
+			return NotImplementedByRemoteError("registry does not implement repository listings")
 		} else {
-			err = newInvalidStatusCodeError(response.StatusCode)
+			return newInvalidStatusCodeError(response.StatusCode)
 		}
 
-		return
-
 	case http.StatusOK:
+		return nil
 
 	default:
-		err = newInvalidStatusCodeError(response.StatusCode)
-		return
+		return newInvalidStatusCodeError(response.StatusCode)
 	}
-
-	return
 }
 
-func (r *registryApi) iterateRepositoryList(lastApiResponse *http.Response, listResponse *repositoryListResponse) (apiResponse *http.Response, more bool, err error) {
-	requestUrl, err := r.paginatedRequestEndpointUrl("v2/_catalog", lastApiResponse)
-
-	if err != nil {
-		return
+func (r *repositoryListRequestContext) processPartialResponse(response paginatedRequestResponse, apiResponse interface{}) {
+	for _, repositoryName := range apiResponse.(*repositoryListJsonResponse).Repositories {
+		response.(*repositoryListResponse).repositories <- newRepository(repositoryName)
 	}
-
-	apiResponse, needsClose, err := r.executeListRequest(requestUrl, lastApiResponse == nil)
-
-	if needsClose {
-		defer apiResponse.Body.Close()
-	}
-
-	if err != nil {
-		return
-	}
-
-	more = apiResponse.Header.Get("link") != ""
-
-	var jsonResponse repositoryListJsonResponse
-	decoder := json.NewDecoder(apiResponse.Body)
-	err = decoder.Decode(&jsonResponse)
-
-	if err != nil {
-		return
-	}
-
-	if jsonResponse.Repositories == nil {
-		err = genericMalformedResponseError
-		return
-	}
-
-	for _, repositoryName := range *jsonResponse.Repositories {
-		listResponse.repositories <- newRepository(repositoryName)
-	}
-
-	return
 }
 
-func (r *registryApi) ListRepositories() (response RepositoryListResponse, err error) {
-	listResponse := &repositoryListResponse{
-		repositories: make(chan Repository, r.pageSize()),
+func (r *repositoryListRequestContext) createResponse(api *registryApi) paginatedRequestResponse {
+	return &repositoryListResponse{
+		repositories: make(chan Repository, api.pageSize()),
 	}
-	response = listResponse
-
-	var apiResponse *http.Response
-	apiResponse, more, err := r.iterateRepositoryList(apiResponse, listResponse)
-
-	go func() {
-		for more {
-			var err error
-			apiResponse, more, err = r.iterateRepositoryList(apiResponse, listResponse)
-
-			if err != nil {
-				listResponse.err = err
-				break
-			}
-		}
-
-		close(listResponse.repositories)
-	}()
-
-	return
+}
+
+func (r *repositoryListRequestContext) createJsonResponse() validatable {
+	return new(repositoryListJsonResponse)
+}
+
+func (r *registryApi) ListRepositories() RepositoryListResponse {
+	return r.paginatedRequest(new(repositoryListRequestContext)).(*repositoryListResponse)
 }

lib/api_tag_list.go

@@ -0,0 +1,92 @@
+package lib
+
+import (
+	"fmt"
+	"net/http"
+)
+
+type tagListResponse struct {
+	tags chan Tag
+	err  error
+}
+
+func (t *tagListResponse) Tags() <-chan Tag {
+	return t.tags
+}
+
+func (t *tagListResponse) LastError() error {
+	return t.err
+}
+
+func (r *tagListResponse) setLastError(err error) {
+	r.err = err
+}
+
+func (r *tagListResponse) close() {
+	close(r.tags)
+}
+
+type tagListJsonResponse struct {
+	RespositoryName string   `json:"name"`
+	Tags            []string `json:"tags"`
+}
+
+func (r *tagListJsonResponse) validate() error {
+	if r.RespositoryName == "" || r.Tags == nil {
+		return genericMalformedResponseError
+	}
+
+	return nil
+}
+
+type tagListRequestContext struct {
+	repositoryName string
+}
+
+func (r *tagListRequestContext) path() string {
+	return fmt.Sprintf("v2/%s/tags/list", r.repositoryName)
+}
+
+func (r *tagListRequestContext) validateApiResponse(response *http.Response, initialRequest bool) error {
+	switch response.StatusCode {
+	case http.StatusUnauthorized, http.StatusForbidden:
+		return genericAuthorizationError
+
+	case http.StatusNotFound:
+		if initialRequest {
+			return newNotFoundError(fmt.Sprintf("%s: no such repository", r.repositoryName))
+		} else {
+			return newInvalidStatusCodeError(response.StatusCode)
+		}
+
+	case http.StatusOK:
+		return nil
+
+	default:
+		return newInvalidStatusCodeError(response.StatusCode)
+	}
+}
+
+func (r *tagListRequestContext) processPartialResponse(response paginatedRequestResponse, apiResponse interface{}) {
+	for _, tagName := range apiResponse.(*tagListJsonResponse).Tags {
+		response.(*tagListResponse).tags <- newTag(tagName, r.repositoryName)
+	}
+}
+
+func (r *tagListRequestContext) createResponse(api *registryApi) paginatedRequestResponse {
+	return &tagListResponse{
+		tags: make(chan Tag, api.pageSize()),
+	}
+}
+
+func (r *tagListRequestContext) createJsonResponse() validatable {
+	return new(tagListJsonResponse)
+}
+
+func (r *registryApi) ListTags(repositoryName string) TagListResponse {
+	ctx := tagListRequestContext{
+		repositoryName: repositoryName,
+	}
+
+	return r.paginatedRequest(&ctx).(*tagListResponse)
+}

lib/tag.go

@@ -0,0 +1,21 @@
+package lib
+
+type tag struct {
+	name           string
+	repositoryName string
+}
+
+func (t *tag) Name() string {
+	return t.name
+}
+
+func (t *tag) RepositoryName() string {
+	return t.repositoryName
+}
+
+func newTag(name, repositoryName string) *tag {
+	return &tag{
+		name:           name,
+		repositoryName: repositoryName,
+	}
+}