Eventhistory Service Configuration

Table of Contents

Introduction
Prerequisites
Consuming
Storing
Retrieving
Configuration
- Environment Variables
- YAML Example

Introduction

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

Prerequisites

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

Consuming

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

Storing

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

Store Type Description

Store Type	Description
`mem`	Basic in-memory store and the default.
`ocmem`	Advanced in-memory store allowing max size.
`Redis`	Stores data in a configured Redis cluster.
`etcd`	Stores data in a configured etcd cluster.
`nats-js`	Stores data using the key-value-store feature of NATS JetStream.
`noop`	Stores nothing. Useful for testing. Not recommended in productive environments.

mem

Basic in-memory store and the default.

ocmem

Advanced in-memory store allowing max size.

Redis

Stores data in a configured Redis cluster.

etcd

Stores data in a configured etcd cluster.

nats-js

Stores data using the key-value-store feature of NATS JetStream.

noop

Stores nothing. Useful for testing. Not recommended in productive environments.

Note that in-memory stores are by nature not reboot persistent.
Though usually not necessary, a database name and a database table can be configured for event stores if the event store supports this. Generally, this does not apply to stores of type in-memory. These settings are blank by default which means that the standard settings of the configured store applies.
Events stay in the store for 2 weeks by default. Use EVENTHISTORY_RECORD_EXPIRY to adjust this value.
The eventhistory service can be scaled if it’s not using in-memory stores and the stores are configured identically over all instances.

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.

Configuration

Environment Variables

The eventhistory service is configured via the following environment variables:

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Environment variables for the eventhistory service
Name	Type	Default Value	Description
`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		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	127.0.0.1:0	The bind address of the GRPC service.
`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.
`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.
`EVENTHISTORY_EVENTS_TLS_ROOT_CA_CERTIFICATE`	string		The root CA certificate used to validate the server’s TLS certificate. If provided NOTIFICATIONS_EVENTS_TLS_INSECURE will be seen as false.
`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_PERSISTENT_STORE` `EVENTHISTORY_STORE` `OCIS_PERSISTENT_STORE_TYPE` `EVENTHISTORY_STORE_TYPE`	string	memory	The type of the eventhistory store. Supported values are: 'memory', 'ocmem', 'etcd', 'redis', 'redis-sentinel', 'nats-js', 'noop'. See the text description for details.
`OCIS_PERSISTENT_STORE_NODES` `EVENTHISTORY_STORE_ADDRESSES`	[]string	[]	A comma separated list of nodes to access the configured store. This has no effect when 'in-memory' stores are configured. Note that the behaviour how nodes are used is dependent on the library of the configured store.
`EVENTHISTORY_STORE_DATABASE`	string	eventhistory	The database name the configured store should use.
`EVENTHISTORY_STORE_TABLE`	string	events	The database table the store should use.
`EVENTHISTORY_RECORD_EXPIRY`	Duration	336h0m0s	Time to live for events in the store. The duration can be set as number followed by a unit identifier like s, m or h. Defaults to '336h' (2 weeks).
`EVENTHISTORY_STORE_SIZE`	int	0	The maximum quantity of items in the store. Only applies when store type 'ocmem' is configured. Defaults to 512.

YAML Example

Note that the filename shown below has been chosen on purpose.
See the Configuration File Naming for details when setting up your own configuration.

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

log:
  level: ""
  pretty: false
  color: false
  file: ""
debug:
  addr: ""
  token: ""
  pprof: false
  zpages: false
grpc:
  addr: 127.0.0.1:0
  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
store:
  store: memory
  nodes: []
  database: eventhistory
  table: events
  record_expiry: 336h0m0s
  size: 0