configurable max message size

Signed-off-by: jkoberg <jkoberg@owncloud.com>

changelog/unreleased/configurable_max_message_size.md

@@ -0,0 +1,5 @@
+Enhancement: configure max message size
+
+Add a configuration option for the grpc max message size
+
+https://github.com/owncloud/ocis/pull/6849

docs/services/general-info/additional-information.md

@@ -0,0 +1,20 @@
+---
+title: Additinal Information
+date: 2018-05-02T00:00:00+00:00
+weight: 20
+geekdocRepo: https://github.com/owncloud/ocis
+geekdocEditPath: edit/master/docs/services/general-info
+geekdocFilePath: additional-information.md
+geekdocCollapseSection: true
+---
+
+This section contains information on general topics
+
+## GRPC Maximum message size
+
+Ocis is using grpc for inter service communication. When having a folder with a lot of files (25000+, size doesn't matter) and doing a `PROPFIND` on the folder, the server will run into errors because the
+grpc message body gets to big. We introduced the envvar `OCIS_GRPC_MAX_RECEIVED_MESSAGE_SIZE` to raise the max size for the grpc body.
+
+NOTE: With a certain amount of files even raising the grpc message size will not suffice as the requests will run into network timeouts. Also generally the more files are in a folder, the longer it will take to load.
+
+It is recommended to use `OCIS_GRPC_MAX_RECEIVED_MESSAGE_SIZE` only temporary to copy files out of the folder (e.g. via web ui) and use the default value in general.

ocis-pkg/shared/shared_types.go

@@ -81,4 +81,8 @@ type Commons struct {
 	SystemUserID      string          `yaml:"system_user_id" env:"OCIS_SYSTEM_USER_ID" desc:"ID of the oCIS storage-system system user. Admins need to set the ID for the storage-system system user in this config option which is then used to reference the user. Any reasonable long string is possible, preferably this would be an UUIDv4 format."`
 	SystemUserAPIKey  string          `mask:"password" yaml:"system_user_api_key" env:"SYSTEM_USER_API_KEY"`
 	AdminUserID       string          `yaml:"admin_user_id" env:"OCIS_ADMIN_USER_ID" desc:"ID of a user, that should receive admin privileges. Consider that the UUID can be encoded in some LDAP deployment configurations like in .ldif files. These need to be decoded beforehand."`
+
+	// NOTE: you will not fing GRPCMaxReceivedMessageSize size being used in the code. The envvar is actually extracted in revas `pool` package: https://github.com/cs3org/reva/blob/edge/pkg/rgrpc/todo/pool/connection.go
+	// It is mentioned here again so it is documented
+	GRPCMaxReceivedMessageSize int `env:"OCIS_GRPC_MAX_RECEIVED_MESSAGE_SIZE" desc:"The maximum body size for grpc requests. Defaults to '10240000'. Note that large values can potentially hide errors and can cause network timeouts. Can be used temporarily to repair unaccessable large folders (25000+ files)"`
 }