Introduce new preview auto-scaling mode for ARC. (#2153)

Co-authored-by: Cory Miller <cory-miller@github.com>
Co-authored-by: Nikola Jokic <nikola-jokic@github.com>
Co-authored-by: Ava Stancu <AvaStancu@github.com>
Co-authored-by: Ferenc Hammerl <fhammerl@github.com>
Co-authored-by: Francesco Renzi <rentziass@github.com>
Co-authored-by: Bassem Dghaidi <Link-@github.com>

github/actions/multi_client.go

@@ -0,0 +1,164 @@
+package actions
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+	"strconv"
+	"sync"
+
+	"github.com/go-logr/logr"
+)
+
+type MultiClient interface {
+	GetClientFor(ctx context.Context, githubConfigURL string, creds ActionsAuth, namespace string) (ActionsService, error)
+	GetClientFromSecret(ctx context.Context, githubConfigURL, namespace string, secretData KubernetesSecretData) (ActionsService, error)
+}
+
+type multiClient struct {
+	// To lock adding and removing of individual clients.
+	mu      sync.Mutex
+	clients map[ActionsClientKey]*actionsClientWrapper
+
+	logger    logr.Logger
+	userAgent string
+}
+
+type GitHubAppAuth struct {
+	AppID             int64
+	AppInstallationID int64
+	AppPrivateKey     string
+}
+
+type ActionsAuth struct {
+	// GitHub App
+	AppCreds *GitHubAppAuth
+
+	// GitHub PAT
+	Token string
+}
+
+type ActionsClientKey struct {
+	ActionsURL string
+	Auth       ActionsAuth
+	Namespace  string
+}
+
+type actionsClientWrapper struct {
+	// To lock client usage when tokens are being refreshed.
+	mu sync.Mutex
+
+	client ActionsService
+}
+
+func NewMultiClient(userAgent string, logger logr.Logger) MultiClient {
+	return &multiClient{
+		mu:        sync.Mutex{},
+		clients:   make(map[ActionsClientKey]*actionsClientWrapper),
+		logger:    logger,
+		userAgent: userAgent,
+	}
+}
+
+func (m *multiClient) GetClientFor(ctx context.Context, githubConfigURL string, creds ActionsAuth, namespace string) (ActionsService, error) {
+	m.logger.Info("retrieve actions client", "githubConfigURL", githubConfigURL, "namespace", namespace)
+
+	parsedGitHubURL, err := url.Parse(githubConfigURL)
+	if err != nil {
+		return nil, err
+	}
+
+	if creds.Token == "" && creds.AppCreds == nil {
+		return nil, fmt.Errorf("no credentials provided. either a PAT or GitHub App credentials should be provided")
+	}
+
+	if creds.Token != "" && creds.AppCreds != nil {
+		return nil, fmt.Errorf("both PAT and GitHub App credentials provided. should only provide one")
+	}
+
+	key := ActionsClientKey{
+		ActionsURL: parsedGitHubURL.String(),
+		Namespace:  namespace,
+	}
+
+	if creds.AppCreds != nil {
+		key.Auth = ActionsAuth{
+			AppCreds: creds.AppCreds,
+		}
+	}
+
+	if creds.Token != "" {
+		key.Auth = ActionsAuth{
+			Token: creds.Token,
+		}
+	}
+
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	clientWrapper, has := m.clients[key]
+	if has {
+		m.logger.Info("using cache client", "githubConfigURL", githubConfigURL, "namespace", namespace)
+		return clientWrapper.client, nil
+	}
+
+	m.logger.Info("creating new client", "githubConfigURL", githubConfigURL, "namespace", namespace)
+
+	client, err := NewClient(ctx, githubConfigURL, &creds, m.userAgent, m.logger)
+	if err != nil {
+		return nil, err
+	}
+
+	m.clients[key] = &actionsClientWrapper{
+		mu:     sync.Mutex{},
+		client: client,
+	}
+
+	m.logger.Info("successfully created new client", "githubConfigURL", githubConfigURL, "namespace", namespace)
+
+	return client, nil
+}
+
+type KubernetesSecretData map[string][]byte
+
+func (m *multiClient) GetClientFromSecret(ctx context.Context, githubConfigURL, namespace string, secretData KubernetesSecretData) (ActionsService, error) {
+	if len(secretData) == 0 {
+		return nil, fmt.Errorf("must provide secret data with either PAT or GitHub App Auth")
+	}
+
+	token := string(secretData["github_token"])
+	hasToken := len(token) > 0
+
+	appID := string(secretData["github_app_id"])
+	appInstallationID := string(secretData["github_app_installation_id"])
+	appPrivateKey := string(secretData["github_app_private_key"])
+	hasGitHubAppAuth := len(appID) > 0 && len(appInstallationID) > 0 && len(appPrivateKey) > 0
+
+	if hasToken && hasGitHubAppAuth {
+		return nil, fmt.Errorf("must provide secret with only PAT or GitHub App Auth to avoid ambiguity in client behavior")
+	}
+
+	if !hasToken && !hasGitHubAppAuth {
+		return nil, fmt.Errorf("neither PAT nor GitHub App Auth credentials provided in secret")
+	}
+
+	auth := ActionsAuth{}
+
+	if hasToken {
+		auth.Token = token
+		return m.GetClientFor(ctx, githubConfigURL, auth, namespace)
+	}
+
+	parsedAppID, err := strconv.ParseInt(appID, 10, 64)
+	if err != nil {
+		return nil, err
+	}
+
+	parsedAppInstallationID, err := strconv.ParseInt(appInstallationID, 10, 64)
+	if err != nil {
+		return nil, err
+	}
+
+	auth.AppCreds = &GitHubAppAuth{AppID: parsedAppID, AppInstallationID: parsedAppInstallationID, AppPrivateKey: appPrivateKey}
+	return m.GetClientFor(ctx, githubConfigURL, auth, namespace)
+}