gRPC Server

An out of process gRPC Adapter which integrates 3scale with Istio

Configuring the adapter

The runtime behaviour of the adapter can be modified by editing the deployment and setting or configuring the following environment variables:

Variable	Description	Default
LISTEN_ADDR	Sets the listen address for the gRPC server	0
LOG_LEVEL	Sets the minimum log output level. Accepted values are one of debug,info,warn,error,none	info
LOG_JSON	Controls whether the log is formatted as JSON	true
LOG_GRPC	Controls whether the log includes gRPC info	false
REPORT_METRICS	Controls whether 3scale system and backend metrics are collected and reported to Prometheus	true
METRICS_PORT	Sets the port which 3scale /metrics endpoint can be scrapped from	8080
CACHE_TTL_SECONDS	Time period, in seconds, to wait before purging expired items from the cache	300
CACHE_REFRESH_SECONDS	Time period in seconds, before a background process attempts to refresh cached entries	180
CACHE_ENTRIES_MAX	Max number of items that can be stored in the cache at any time. Set to 0 to disable caching	1000
CACHE_REFRESH_RETRIES	Sets the number of times unreachable hosts will be retried during a cache update loop	1
ALLOW_INSECURE_CONN	Allow to skip certificate verification when calling 3scale API's. Enabling is not recommended	false
ROOT_CA	Path to root CA file using PEM format	N/A
CLIENT_CERT	Path to client certificate (public key) using PEM format (requires CLIENT_KEY)	N/A
CLIENT_KEY	Path to client key (private key) using PEM format (requires CLIENT_CERT)	N/A
CLIENT_TIMEOUT_SECONDS	Sets the number of seconds to wait before terminating requests to 3scale System and Backend	10
GRPC_CONN_MAX_SECONDS	Sets the maximum amount of seconds (+/-10% jitter) a connection may exist before it will be closed	60
USE_CACHED_BACKEND	If true, attempt to create an in-memory apisonator cache for authorization requests	false
BACKEND_CACHE_FLUSH_INTERVAL_SECONDS	If the backend cache is enabled, this sets the interval in seconds for flushing the cache against 3scale	15
BACKEND_CACHE_POLICY_FAIL_CLOSED	Whenever the backend cache cannot retrieve authorization data, whether to deny (closed) or allow (open) requests	true

Configuration Caching Behaviour

By default, responses from 3scale System API's will be cached. Entries will be purged from the cache when they become older than the CACHE_TTL_SECONDS value. Again by default however, automatic refreshing of cached entries will be attempted some seconds before they expire, based on the CACHE_REFRESH_SECONDS value. Automatic refreshing can be disabled by setting this value higher than the CACHE_TTL_SECONDS value.

Caching can be disabled entirely by setting CACHE_ENTRIES_MAX to a non-positive value.

Through the refreshing process, cached values whose hosts become unreachable will be retried before eventually being purged when past their expiry.