DSS System Services

Glossary Item Box

DSS System Services

Regardless of which programming language has been chosen for the task of writing services, see Choosing Programming Language, the programmer can take advantage of a set of system services that come as part of any language using Decentralized Software Services DSS node. The system services provide support for common functions ranging from directory services, accessing the file system, logging and diagnostics, and security to construction of new service instances. The system services can be used by any service running within a DSS node. Also because DSS is inherently distributed, depending on your DSS Node Security Model configuration, these services can also be accessed remotely.

By starting a DSS Node from a DSS command prompt like this

dsshost /p:50000

or by selecting, Run DSS Node, from the Start menu, it is possible to see many of the system services in action by accessing this URI in your Web browser.

https://localhost:50000

Control Panel Service

The control panel is a useful service for manually starting and stopping services and also for inspecting the contract of available services.

Constructor Service

The constructor service creates new instances of services. While services can talk directly to the constructor service, they often use higher level primitives such as manifests  or partners. See DSS Service Components) or DSS Service Manifests.

Manifest Loader Service

The manifest loader service, loads manifests and submits each request for creating a service instance to the constructor service.

Service Directory Service

The service directory, service is a simple directory of service instances running on a DSS node. Services can choose to not register themselves in the directory but the default behavior is that all service instances are registered. As part of the service directory, it is possible to see the partners associated with each service instance. See DSS Service Components.

Contract Directory Service

The contract directory scans the bin folder, and possibly other folders, for service assemblies that are available on that DSS node. Only services for which a service assembly has been found can be created on any given DSS node.

Mount Service

The mount service allows services to expose files through a DSS node and to save and retrieve such files. Only the part of the file system that is below the installation folder of DSS is exposed in this manner.

Embedded Resource Service

The embedded resource service allows services to expose embedded resources through a DSS node. By default, embedded resources are not available through a DSS node but by explicitly registering them with the embedded resource service, they can be accessed for read-only by other services.

Subscription Manager Service 

The subscription manager service is a helper service that can manage subscriptions so that each service does not have to do it on its own. The subscription manager is typically set up as a partner with a different subscription manager service instance for each service using it as a partner. See Service Tutorials Overview for several tutorials using the subscription manager to manage subscriptions as well as Subscription Model Overview for a detailed description of how to use this service).

Partner Manager Service

The partner manager service is another helper service that maintains the active partners associated with a service instance.

Console Output Service

The console output service exposes debug and log messages generated when the DSS node is running. The console service is effectively a structured console where messages can be of arbitrary complexity and subscribers to the console service can filter exactly which messages they are interested in.

Resource Diagnostics Service

The resource diagnostics service provides current information about the amount of messages processed or pending in the system.

Security Manager Service

The security manager service enables configuration of the security policy for a node. See DSS Node Security Model.

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