Eventhistory

Abstract

The eventhistory consumes all events from the configured event system like NATS, stores them and allows other services to retrieve them via an event ID.

Prerequisites
Consuming
Storing
Retrieving
Example Yaml Config

Prerequisites

Running the eventhistory service without an event system like NATS is not possible.

Consuming

The eventhistory services consumes all events from the configured event system.

Storing

The eventhistory service stores each consumed event via the configured store in EVENTHISTORY_STORE. Possible stores are:

memory: Basic in-memory store and the default.
redis-sentinel: Stores data in a configured Redis Sentinel cluster.
nats-js-kv: Stores data using key-value-store feature of nats jetstream
noop: Stores nothing. Useful for testing. Not recommended in production environments.

Other store types may work but are not supported currently.

Note: The service can only be scaled if not using memory store and the stores are configured identically over all instances!

Note that if you have used one of the deprecated stores, you should reconfigure to one of the supported ones as the deprecated stores will be removed in a later version.

Store specific notes:

When using redis-sentinel, the Redis master to use is configured via e.g. OCIS_CACHE_STORE_NODES in the form of <sentinel-host>:<sentinel-port>/<redis-master> like 10.10.0.200:26379/mymaster.
When using nats-js-kv it is recommended to set OCIS_CACHE_STORE_NODES to the same value as OCIS_EVENTS_ENDPOINT. That way the cache uses the same nats instance as the event bus.
When using the nats-js-kv store, it is possible to set OCIS_CACHE_DISABLE_PERSISTENCE to instruct nats to not persist cache data on disc.

Retrieving

Other services can call the eventhistory service via a gRPC call to retrieve events. The request must contain the event ID that should be retrieved.

Example Yaml Config

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# Autogenerated
# Filename: eventhistory-config-example.yaml

tracing:
  enabled: false
  type: ""
  endpoint: ""
  collector: ""
log:
  level: ""
  pretty: false
  color: false
  file: ""
debug:
  addr: 127.0.0.1:9270
  token: ""
  pprof: false
  zpages: false
grpc:
  addr: 127.0.0.1:9274
  tls: null
grpc_client_tls: null
events:
  endpoint: 127.0.0.1:9233
  cluster: ocis-cluster
  tls_insecure: false
  tls_root_ca_certificate: ""
  enable_tls: false
  username: ""
  password: ""
store:
  store: nats-js-kv
  nodes:
  - 127.0.0.1:9233
  database: eventhistory
  table: ""
  ttl: 336h0m0s
  username: ""
  password: ""

Environment Variables

Name	Type	Default Value	Description
OCIS_TRACING_ENABLED EVENTHISTORY_TRACING_ENABLED	bool	false	Activates tracing.
OCIS_TRACING_TYPE EVENTHISTORY_TRACING_TYPE	string		The type of tracing. Defaults to ‘’, which is the same as ‘jaeger’. Allowed tracing types are ‘jaeger’ and ’’ as of now.
OCIS_TRACING_ENDPOINT EVENTHISTORY_TRACING_ENDPOINT	string		The endpoint of the tracing agent.
OCIS_TRACING_COLLECTOR EVENTHISTORY_TRACING_COLLECTOR	string		The HTTP endpoint for sending spans directly to a collector, i.e. http://jaeger-collector:14268/api/traces. Only used if the tracing endpoint is unset.
OCIS_LOG_LEVEL EVENTHISTORY_LOG_LEVEL	string		The log level. Valid values are: ‘panic’, ‘fatal’, ’error’, ‘warn’, ‘info’, ‘debug’, ’trace’.
OCIS_LOG_PRETTY EVENTHISTORY_LOG_PRETTY	bool	false	Activates pretty log output.
OCIS_LOG_COLOR EVENTHISTORY_LOG_COLOR	bool	false	Activates colorized log output.
OCIS_LOG_FILE EVENTHISTORY_LOG_FILE	string		The path to the log file. Activates logging to this file if set.
EVENTHISTORY_DEBUG_ADDR	string	127.0.0.1:9270	Bind address of the debug server, where metrics, health, config and debug endpoints will be exposed.
EVENTHISTORY_DEBUG_TOKEN	string		Token to secure the metrics endpoint.
EVENTHISTORY_DEBUG_PPROF	bool	false	Enables pprof, which can be used for profiling.
EVENTHISTORY_DEBUG_ZPAGES	bool	false	Enables zpages, which can be used for collecting and viewing in-memory traces.
EVENTHISTORY_GRPC_ADDR	string	127.0.0.1:9274	The bind address of the GRPC service.
OCIS_EVENTS_ENDPOINT EVENTHISTORY_EVENTS_ENDPOINT	string	127.0.0.1:9233	The address of the event system. The event system is the message queuing service. It is used as message broker for the microservice architecture.
OCIS_EVENTS_CLUSTER EVENTHISTORY_EVENTS_CLUSTER	string	ocis-cluster	The clusterID of the event system. The event system is the message queuing service. It is used as message broker for the microservice architecture. Mandatory when using NATS as event system.
OCIS_INSECURE EVENTHISTORY_EVENTS_TLS_INSECURE	bool	false	Whether to verify the server TLS certificates.
OCIS_EVENTS_TLS_ROOT_CA_CERTIFICATE EVENTHISTORY_EVENTS_TLS_ROOT_CA_CERTIFICATE	string		The root CA certificate used to validate the server’s TLS certificate. Will be seen as empty if NOTIFICATIONS_EVENTS_TLS_INSECURE is provided.
OCIS_EVENTS_ENABLE_TLS EVENTHISTORY_EVENTS_ENABLE_TLS	bool	false	Enable TLS for the connection to the events broker. The events broker is the ocis service which receives and delivers events between the services.
OCIS_EVENTS_AUTH_USERNAME EVENTHISTORY_EVENTS_AUTH_USERNAME	string		The username to authenticate with the events broker. The events broker is the ocis service which receives and delivers events between the services.
OCIS_EVENTS_AUTH_PASSWORD EVENTHISTORY_EVENTS_AUTH_PASSWORD	string		The password to authenticate with the events broker. The events broker is the ocis service which receives and delivers events between the services.
OCIS_PERSISTENT_STORE EVENTHISTORY_STORE	string	nats-js-kv	The type of the store. Supported values are: ‘memory’, ’nats-js-kv’, ‘redis-sentinel’, ’noop’. See the text description for details.
OCIS_PERSISTENT_STORE_NODES EVENTHISTORY_STORE_NODES	[]string	[127.0.0.1:9233]	A list of nodes to access the configured store. This has no effect when ‘memory’ store is configured. Note that the behaviour how nodes are used is dependent on the library of the configured store. See the Environment Variable Types description for more details.
EVENTHISTORY_STORE_DATABASE	string	eventhistory	The database name the configured store should use.
EVENTHISTORY_STORE_TABLE	string		The database table the store should use.
OCIS_PERSISTENT_STORE_TTL EVENTHISTORY_STORE_TTL	Duration	336h0m0s	Time to live for events in the store. Defaults to ‘336h’ (2 weeks). See the Environment Variable Types description for more details.
OCIS_PERSISTENT_STORE_AUTH_USERNAME EVENTHISTORY_STORE_AUTH_USERNAME	string		The username to authenticate with the store. Only applies when store type ’nats-js-kv’ is configured.
OCIS_PERSISTENT_STORE_AUTH_PASSWORD EVENTHISTORY_STORE_AUTH_PASSWORD	string		The password to authenticate with the store. Only applies when store type ’nats-js-kv’ is configured.