slog to stdout and use default driver (transparency-dev#778)

* stdout

* default driver

Author: phbnf

cmd/tesseract/gcp/main.go

@@ -123,7 +123,7 @@ func main() {
 	flag.Parse()
 	ctx := context.Background()
 
-	var logWriter io.Writer = os.Stderr
+	var logWriter io.Writer = os.Stdout
 	var logClient *logging.Client
 
 	if *logToCloudAPI {

deployment/modules/gcp/gce/tesseract/main.tf

@@ -30,7 +30,6 @@ locals {
     # Map the port
     "-p 80:80",
     # Ensure that TesseraCT logs are delivered to GCP logging.
-    "--log-driver=gcplogs",
     # Bind-mount the witness policy, if one has been provided.
     var.witness_policy == "" ? "" : "--mount type=bind,src=${local.witness_policy_file},dst=${local.witness_policy_file}",
     # Bind-mount the roots file, if one has been provided.