System Properties Introduction

System properties are a domain-based key-value store that can be used to store persistent configuration information for Qorus interfaces. In the context of Qorus system properties, a "domain" is simply a name that groups together key-value pairs. Keys are strings, and values are any Qore value that can be serialized to YAML.

System Properties Overview

Component	Description
`domain`	a string of up to 240 bytes used to group key-value pairs; domain names are unique and case-sensitive
`key`	a string of up to 240 bytes that uniquely identifies a value within a domain; key names are case-sensitive
`value`	Any Qore value that can be serialized to YAML in less or equal to than 4000 bytes

Note

System properties are stored in the SYSTEM_PROPERTIES table in the Qorus system schema; the data size limitations listed in the table above are due to column constraints in this table.
YAML serialization incurs a small overhead of at least 4 bytes; trying to store a larger value will cause a PROP-ERROR exception to be thrown
All system property operations are protected by a read-write lock and are therefore atomic in respect to simultaneous actions in multiple threads

The "omq" domain is protected; it contains system reference information and cannot be updated.

System Properties APIs

System properties can be created, updated, read, and deleted using REST APIs, internal function calls, and from the command line.

Note: To delete a system property; call the function or network API to set the value, and omit the value; this will cause the system property key to be deleted; when the last key is deleted, the system property domain is deleted as well.

System Properties REST APIs

Action	REST URI Request
read	- GET /api/latest/system/props - GET /api/latest/system/props/{domain} - GET /api/latest/system/props/{domain}/{key}
create, update, delete	- PUT /api/latest/system/props?action=replaceAll - PUT /api/latest/system/props?action=set - PUT /api/latest/system/props?action=updateMany - PUT /api/latest/system/props/{domain}?action=set - PUT /api/latest/system/props/{domain}?action=updateMany - PUT /api/latest/system/props/{domain}/{key}?action=set

System Properties Functions

Method	Availability
MapperApi::propGet()	Mappers
UserApi::propGet()	All user server code (workflows, services, jobs) and the Qorus client library
UserApi::propUpdate()	workflows, services, jobs and the Qorus client library

System Properties Command-Line Programs

Program	Description
oprop	The primary command-line interface to system properties; uses the REST API
qrest	The raw REST client; can be used to query and set system properties directly with the REST API
ocmd	The RPC command-line API interface; can be used to query and set system properties using the deprecated system.prop service

Note: the system.prop service is deprecated; the REST API or internal API functions should be used instead to access and manipulate system properties

System Properties Examples

REST Examples

qrest get system/props
qrest get system/props/omq
qrest get system/props/omq/value

Method Example

string ds = UserApi::propGet("mydomain", "myds") ?? "default_value";

Command-line Example

oprop get mydomain myds
oprop set mydomain hash key1=value,key2=value

Table of Contents

System Properties Introduction

System Properties APIs

System Properties Examples