lakectl: share a single API client across a command invocation

cmd/lakectl/cmd/root.go

@@ -203,6 +203,9 @@ var (
 	tokenCache          *awsiam.JWTCache
 	tokenCacheOnce      sync.Once
 	ErrTokenUnavailable = fmt.Errorf("token is not available")
+
+	apiClient     *apigen.ClientWithResponses
+	apiClientOnce sync.Once
 )
 
 func withRecursiveFlag(cmd *cobra.Command, usage string) {
@@ -615,7 +618,19 @@ func newAWSIAMAuthProviderConfig() (*awsiam.IAMAuthParams, error) {
 	return awsiam.NewIAMAuthParams(host, opts...), nil
 }
 
+// getClient returns the process-wide API client. All callers — including the
+// pre-run usage-stats report — share one client and therefore one underlying
+// HTTP connection pool: a lakectl invocation opens a single TCP+TLS connection
+// to the server instead of one per client construction, which matters when
+// lakectl is invoked at high frequency (e.g. once per file in a pipeline).
 func getClient() *apigen.ClientWithResponses {
+	apiClientOnce.Do(func() {
+		apiClient = newAPIClient()
+	})
+	return apiClient
+}
+
+func newAPIClient() *apigen.ClientWithResponses {
 	httpClient := getHTTPClient(lakectlRetryPolicy)
 	accessKeyID := cfg.Credentials.AccessKeyID
 	secretAccessKey := cfg.Credentials.SecretAccessKey

cmd/lakectl/cmd/root_test.go

@@ -10,6 +10,7 @@ import (
 	"path/filepath"
 	"runtime"
 	"strings"
+	"sync"
 	"testing"
 
 	"github.com/go-openapi/swag"
@@ -346,7 +347,10 @@ func TestMaybeWarnEnterprise(t *testing.T) {
 
 	originalCfg := cfg
 	cfg = &Configuration{}
-	defer func() { cfg = originalCfg }()
+	defer func() {
+		cfg = originalCfg
+		resetAPIClientCache()
+	}()
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -362,6 +366,9 @@ func TestMaybeWarnEnterprise(t *testing.T) {
 			}))
 			defer server.Close()
 			cfg.Server.EndpointURL = lakefsconfig.OnlyString(server.URL)
+			// getClient memoizes the API client; clear it so this subtest's
+			// endpoint takes effect.
+			resetAPIClientCache()
 
 			var buf bytes.Buffer
 			tt.cmd.SetContext(t.Context())
@@ -376,3 +383,10 @@ func TestMaybeWarnEnterprise(t *testing.T) {
 		})
 	}
 }
+
+// resetAPIClientCache clears the memoized API client so a test can point
+// getClient at a different server endpoint.
+func resetAPIClientCache() {
+	apiClient = nil
+	apiClientOnce = sync.Once{}
+}