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rsrc attributes 3.3 design

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Steve Jones edited this page Sep 6, 2017 · 3 revisions

Table of Contents

Overview

Implement or update (when noted) resource attributes for the following:

  • Images (update)
  • Instances
  • Snapshots
  • Volumes
Resource attribute names are strings, values (can be) structured data. When updating an attribute with a structured value, the caller specifies which part of the value will be updated.

Analysis

Open Issues

Design

Resource Attributes

Resource attributes are already implemented for Images. As part of this feature we should clean up this implementation.

Service Impact

Messages, Query/SOAP bindings and services will need some updates (no major changes anticipated)

The required attribute operations (some of Describe, Modify, Reset) will have placement as follows:

Type Manager
Image com.eucalyptus.images.ImageManager (existing methods updated)
Instance com.eucalyptus.vm.VmControl (has stubs)
Snapshot com.eucalyptus.blockstorage.SnapshotManager (has stubs)
Volume com.eucalyptus.blockstorage.VolumeManager

NOTE: Snapshot and volume operations depend on inclusion of other features (Snaphost launch permission, product code propagation)

SOAP Binding

A client tool is required for testing SOAP bindings (older AWS SDK?)

Permissions

IAM / resource ownership (account) dictate which attributes can be read or updated. Users in the eucalyptus account can access all resource attributes.

Attribute Describe

Read of attributes can be implemented using a Map: 

  Map<String,AttributeGetter<R,V>>

Where R is the response message type and V is the resource value.

For each attribute there will be an AttributeGetter in the map that knows how to populate the value. 

  AttributeGetter
  - get( R, V ) // Populate R from V

Attribute Modify

Update of attributes can be implemented with a collection of setters: 

  Collection<AttributeSetter<R,V>>

Where R is the request message, and V is the resource value.

Each setter would be matched against the requests message, only one setting is allowed to match (only one attribute update per request).

The matched setter is then invoked to (perhaps partially) update the attribute value. 

  AttributeSetter
  - bool match( R )
  - bool set( R, V ) // Set value on V from R

The success of the setter is reflected in the success of the overall operation.

Attribute Reset

Reset of attributes can be implemented using a Map: 

  Map<String,AttributeResetter<V>>

Where V is the resource value.

For each attribute there will be an AttributeResetter in the map that knows how to reset the value. 

  AttributeResetter
  - bool reset( V ) // Populate R from V

TODO or just use a Predicate for this.

The success of the setter is reflected in the success of the overall operation.

Instances

For instances, some attributes may only be updated when the instance is stopped. When this precondition is violated the correct error should be returned.

Restrictions on instance attributes that can be modifed when running mean that it is not required to keep a (readonly) copy of the instance configuration. Instance attributes that can be modified when running are:

  • disableApiTermination
  • instanceInitiatedShutdownBehavior
  • blockDeviceMapping delete on terminate setting (multiple)

Integration Areas

IAM: operations access controlled via IAM policies

Upgrade

No upgrade impact noted.

Packaging

No specific packaging requirements.

Documentation

No specific documentation items noted.

Security

No specific security concerns are noted for this design.

Testing

Testing should cover SOAP and Query APIs

References

tag:rls-3.3 tag:rsrc-attributes
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