fix: increase max grpc message size (#4869)

Signed-off-by: Alexander Matyushentsev <AMatyushentsev@gmail.com>

docs/operator-manual/high_availability.md

@@ -92,6 +92,11 @@ non-preferred version and causes performance issues.
 
 The `argocd-server` is stateless and probably least likely to cause issues. You might consider increasing number of replicas to 3 or more to ensure there is no downtime during upgrades.
 
+**settings:**
+
+* The `ARGOCD_GRPC_MAX_SIZE_MB` environment variable allows specifying the max size of the server response message in megabytes.
+The default value is 200. You might need to increase for an Argo CD instance that manages 3000+ applications.    
+
 ### argocd-dex-server, argocd-redis
 
 The `argocd-dex-server` uses an in-memory database, and two or more instances would have inconsistent data. `argocd-redis` is pre-configured with the understanding of only three total redis servers/sentinels.

pkg/apiclient/apiclient.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
+	"math"
 	"net"
 	"net/http"
 	"os"
@@ -39,6 +40,7 @@ import (
 	versionpkg "github.com/argoproj/argo-cd/pkg/apiclient/version"
 	"github.com/argoproj/argo-cd/pkg/apis/application/v1alpha1"
 	argoappv1 "github.com/argoproj/argo-cd/pkg/apis/application/v1alpha1"
+	"github.com/argoproj/argo-cd/util/env"
 	grpc_util "github.com/argoproj/argo-cd/util/grpc"
 	argoio "github.com/argoproj/argo-cd/util/io"
 	"github.com/argoproj/argo-cd/util/kube"
@@ -53,8 +55,13 @@ const (
 	EnvArgoCDServer = "ARGOCD_SERVER"
 	// EnvArgoCDAuthToken is the environment variable to look for an Argo CD auth token
 	EnvArgoCDAuthToken = "ARGOCD_AUTH_TOKEN"
+	// EnvArgoCDgRPCMaxSizeMB is the environment variable to look for a max gRPC message size
+	EnvArgoCDgRPCMaxSizeMB = "ARGOCD_GRPC_MAX_SIZE_MB"
+)
+
+var (
 	// MaxGRPCMessageSize contains max grpc message size
-	MaxGRPCMessageSize = 100 * 1024 * 1024
+	MaxGRPCMessageSize = env.ParseNumFromEnv(EnvArgoCDgRPCMaxSizeMB, 200, 0, math.MaxInt32) * 1024 * 1024
 )
 
 // Client defines an interface for interaction with an Argo CD server.