Network Working Group J. Algermissen
Internet-Draft Jan Algermissen Solutions Engineering
Intended status: Informational March 03, 2019
Expires: September 4, 2019
Digital Product Life Cycle Model
draft-algermissen-digital-product-life-cycle-model-00
Abstract
This specification defines an abstract model for Digital Products and
their relationships with each other in order to establish a basic
abstraction on which the lifecycle of Digital Products and
collaborations around them can be expressed. In addition, this
specification defines a number of message formats and hypermedia
controls, to enable the creation of tools and application in the
space of Digital Product Life Cycle Management.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 4, 2019.
Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. The Digital Product Life Cycle Model . . . . . . . . . . . . 4
4. Services . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Execution Environment Types . . . . . . . . . . . . . . . . . 6
6. Digital Product Composition Model . . . . . . . . . . . . . . 8
7. Product Documents . . . . . . . . . . . . . . . . . . . . . . 10
8. Stage Sets . . . . . . . . . . . . . . . . . . . . . . . . . 11
9. The Stage Set JSON Object . . . . . . . . . . . . . . . . . . 12
10. Delivery Fabrics . . . . . . . . . . . . . . . . . . . . . . 13
11. Extension Resource Families . . . . . . . . . . . . . . . . . 13
12. Well Defined Execution Environment Variables . . . . . . . . 13
13. Example Implementations . . . . . . . . . . . . . . . . . . . 14
14. Security Considerations . . . . . . . . . . . . . . . . . . . 14
15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
16. References . . . . . . . . . . . . . . . . . . . . . . . . . 16
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 18
Appendix B. Implementation Notes . . . . . . . . . . . . . . . . 18
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction
A wide variety of applications exists that support the journey of
developers and other collaborators around the lifecycle of digital
products.
The aim of this specification is to facilitate integration options
between such tools and applications by providing a common abstraction
and coordination protocols.
The abstract model differentiates between the notion of a Digital
Product and any system or infrastructure configurations and
installations created to facilitate collaboration around such digital
products. A Digital Product in itself is purely abstract, primarily
acting as a nexus for accountability and collaboration.
Associated with Digital Products is a life cycle model that provides
an abstraction of the individual phases in which a Digital Product
lives to actually produce value. Collaboration of various actors is
also logically organised on the basis of these phases.
Collaboration and value creation only becomes possible if
corresponding tooling or infrastructure is provided beyond the
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intangible notion of a Digital Product. For each of the life cycle
phases a resource abstraction is defined in order to establish a
model around which software can be created for creation and
management of such life cycle specific resources.
On top of this semantic foundation provided by these abstract models,
this specification defines a number of message formats, hypermedia
controls, and component roles that enable the creation of
collaboration software systems and tools.
1.1. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. Glossary
Throughout this specification the following terms are used with
specific meaning as defined below:
o Resource Family: An abstaction of coordinated resources that
support a specific kind of usecase, such as deploying and running
a product in some infrastructure or performing build, test,
packaging, and publishing of products.
o Resource Family Descriptor: A file or network message containing a
description of a desired instance of a resource family, for
example a stage set definition file.
o Resource Manager: A software system that processes resource family
descritors and creates or updates infrastructure accordingly.
Examples are the creation of CI/CD pipelines and associated test
systems, the creation of collaboration tool spaces and channels.
o Resource Manager Client: A software system that interacts with a
resource manager.
o Provisioning Strategy: The specifics of the implementation how a
given resource manager chooses to turn the abstract resource
family descriptor into actually created structures. For example,
a stage set resource manager could implement a strategy that puts
all stage sets into a single account with shared runtimes and PaaS
instances, or it could implement a strategy, where every processed
stage set is provided an isolated environment.
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The following resource families are define by this specification:
* Product Management Environment (TBD)
* Stage Set
* Delivery Fabric (TBD)
* Operations Cockpit (TBD)
* Report Workbench (TBD)
3. The Digital Product Life Cycle Model
This specification differentiates the following Digital Products
Lifecycle aspects:
o Journey Portfolio Management Model
o Product Management Model
o Product Composition Model
o Product Content Model
o Product Delivery Model
o Product Deployment Model
o Product Operations Model
4. Services
The Digital Product Life Cycle Model aims to facilitate the
integration into existing Internet technology and thus uses existing
specified semantics whenever possible.
One of such integration points is the notion of _Service_, which
refers to an abstract capability associated with an interaction
protocol expectation. This specification uses the term _Service_ in
the exact same sense as it is used by the various specifications
available through the IETF.
Some relevant specifications are [RFC3232]. [RFC2782], [RFC6763].
On the one hand services are used by capability providing software
systems to advertise that they meet the contract associated with a
given service name, or in other words, that the providing system
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meets the expectations of consuming systems of a given service. On
the other hand, services are used by consuming systems to express
that they have certain protocol and capability expectations when
interacting with a providing system.
While services in most existing specifications are rather protocol
focussed, the service notion seamlessly supports referring to
capabilities that exist in more functional areas. The following
examples show services that illustrate the notion of _servciew_ as
understood by this specification:
'search', 'suggest', 'basket', 'ftp', 'postgres', 'smtp', 'http',
'aws-dynamo', 'gcp-pubsub', 'google-maps',...
4.1. Service Names
Service names MUST conform to the syntax requirements stated in
[RFC1034], meaning that service names MUST only consist of ASCII
letters, digits, and hyphens and that they MUST NOT be longer than 15
characters.
Service names are case insensitive.
TBD: Differentiate between standardized global services and context-
based services
4.2. Port Numbers
Services MAY be assigned a port number, see [RFC3232] and
https://www.iana.org/assignments/port-numbers
4.3. Service Catalog
In order to express dependencies of a product on one or more
services, the list of services available in a given context must be
known. Systems that have the ability to manage dependencies SHOULD
expose service catalogs that list the available services.
4.4. The service-catalog Link Relation Type
Links with the link relation type 'service-catalog' indicate that the
target resource represents a service catalog.
4.5. Service List Documents
The canonical model for a service list document is a JSON [RFC8259]
object.
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When serialized as a JSON document, that format is identified with
the "application/vnd.ply.servicelist+json" media type.
4.5.1. Syntax Example
{
"services" : [
{
"name" : "",
"description" : "...",
"docs" : [ "" , "" ]
},
{
"name" : "",
"description" : "...",
"docs" : [ "" , "" ]
}
]
}
5. Execution Environment Types
Common to all software systems is the differentiation between
something being developed and actually running it in a given context.
The things being develop are inherently bound to the target type of
execution environment. This specification defines the notion of
_Execution Environment Type_ in order to capture this property of
developed software items. An Execution Environment is anyting into
which a developed software can be deployed to realize its
capabilities in a given runtime environment.
Examples of Execution Environment Types are the usual environments
such as "Linux Operating System", "Docker", "AWS Lambda", "Java
Application Server", "Oracle PL/SQL", but other possible runnable
artefacts and Execution Environment Types are "Single Page
Applications deployed to a CDN", "The configuration of an integration
proxy", "A native mobile app deployed on a mobile phone".
5.1. Execution Environment Type Definitions
Execution Environment Types establish a contract between product
component developers and processors of component deployments and
developers need to understand this contract when they develop the
component. For example, part of this contract is the definition of
how the well known environment variables are provided to the
component at runtime. Another part is how component artifacts must
be published before or during deployment.
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The contract established by a given Execution Environment Type must
be made availble to the users as Execution Environment Type
Definitions and must convey the fopllowing information:
5.1.1. Name
The identifier and name of the execution environment type.
5.1.2. Description
A detailed description of the contract in a way that is sufficient
for the user to develop components and publish them. Specifically
this MUST include
o What is the expected artifact build and packaging format?
o What is the expected runtime behaviour (TBD: explain)
o What are the startup and shutdown constraints
o What are the deployment parameters that MUST, SHOULD, or MAY be
passed as party of deployment (eg cmount CPU)
o How are the environment variables passed to the component at
runtime?
o How are secrets pertaining to individual variable values provided?
o Anything else the developer needs to know the execution
environment will expect from her software.
5.2. Execution Environment Variables
TBD
5.3. Execution Environment Type Catalog
Systems that support the deployment of software artifacts SHOULD
provide an execution evironment type catalog to inform client systems
about the supported execution environments.
5.4. The 'execenv-catalog' Link Relation Type
Links with the link relation type 'execenv-catalog' indicate that the
target resource represents an execution environment type catalog.
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5.5. Execution Environment Type List Documents
TBD
The canonical model for an execution environment document is a JSON
[RFC8259] object.
When serialized as a JSON document, that format is identified with
the "application/vnd.ply.execenvlist+json" media type.
5.5.1. Syntax Example
{
"execenvs" : [
{
"name" : "",
"description" : "...",
"docs" : [ "" , "" ] },
{
"name" : "",
"description" : "...",
"docs" : [ "" , "" ]
}
]
}
6. Digital Product Composition Model
A digital product is understood to consist of components. Components
can have dependencies on services. Services are either backing
systems like databases or they are external services, such as a
search API, a backend IT system, or another product in the sense of
'product' used in this specification.
Components can share dependencies that are specific to a product, but
no two products may share the same service instances.
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+-----------------------------------+
| Product |
| ~~~~~~~ |
| -name |
| |
| +-----------+ +-----------+ | +-------+
| | Component | | Component +--+-- implements ->|Service|
| | ~~~~~~~~~ | | ~~~~~~~~~ | | +-------+
| | -name | | -name | |
| | -type | | -type | |
| +----+-+----+ +-----+-----+ |
| | | | |
| | +----------------+ |
| | | |
| V V |
| +----------+ +----------+ |
| |Dependency| |Dependency| |
| |-name | |-name | |
| +-----+----+ +----+-----+ |
| | | |
+--------+-----------------+--------+
| |
V V
+-------+ +-------+
|Service| |Service|
+-------+ +-------+
6.1. Product
TBD
6.1.1. Product Name Attribute
Product objects MUST exhibit a "name" property with a string literal
value which conforms to the syntax requirements for DNS labels. The
labels must follow the rules for ARPANET host names. They must start
with a letter, end with a letter or digit, and have as interior
characters only letters, digits, and hyphen. There are also some
restrictions on the length. Labels must be 63 characters or less
([RFC2181]).
6.2. Component
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6.2.1. Component Name Attribute
Component objects MUST exhibit a "name" property with a string
literal value which conforms to the syntax requirements for DNS
labels. The labels must follow the rules for ARPANET host names.
They must start with a letter, end with a letter or digit, and have
as interior characters only letters, digits, and hyphen. There are
also some restrictions on the length. Labels must be 63 characters
or less ([RFC2181]).
6.2.2. Component Type Attribute
Components have an Execution Environment Type indicated by the 'type'
attribute.
6.3. Dependency
TBD
Dependencies are named to differentiate between them. This makes it
possible for a product to exhibit one or more dependencies on the
same service.
6.4. Service Implementation
When products expose capabilities for use by other products, they
must expose them in order for other products to consume them as
dependencies.
7. Product Documents
In order to communicate product and product structure information
between systems, this specification defines a syntax for product
documents. In addition to the structural product information,
product documents contain syntax elements that enable the
coordination between resource managers and resource manager clients.
Resource managers SHOULD use these syntax elements to embed discovery
information into product data to enable resource manager clients to
determine where to send product data- or resource descriptor updates
and where to retrieve update status information.
Resource manager clients SHOULD leverage the discovery elements as
much as possible and understand product documents as the primary
means of coordination between resource managers and clients.
Focussing resource manager client development on the semantics of
product documents and other hypermedia elements defined in this
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specification enables the creation of generic user agents for any
resource manager implementation. In other words, resource manager
clients SHOULD not rely on specific aspects of a certain resource
manager instance to avoid coupling the client to the original design
of that specific manager.
7.1. The Product JSON Object
The canonical model for a product document is a JSON [RFC8259]
object.
When serialized as a JSON document, that format is identified with
the "application/vnd.ply.product+json" media type.
7.2. A YAML-formatted example of a product model
name: search
dependencies:
- name: index
service: solr
- name: config
service: postgres
components:
- name: importer
dependencies: ["index","config"]
- name: searcher
dependencies: ["index"]
implements: ["opensearch","my-suggest"]
8. Stage Sets
Stage Sets are a resource family that enables the creation of sets of
related stages in a given infrastructure providing system. Resource
Managers that accepts the processing of stage sets, are expected to
create and configure infrastructure accoring to the desired target
state as abstractly expressed in the processed state set.
Many stage sets can be defined for any given product and different
resource managers can be chosen to be responsible for any number of
such stage sets.
For example, one might choose (1) to apply one resource manager to a
public cloud provider for managing the main delivery stages there,
(2) to apply another resource manager to an on-premise infrastructure
and manage individual, short lived, per-feature branch test stages in
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a cheaper environment, and (3), developers could use a local resource
manager to manage local development stages and generate Docker
Compose-based running systems from them.
Therefore, stage sets enable a fully decentralized management of sets
of related stages with, propably independent, collaborators or
software systems.
By allowing unrelated resource managers to manage unrelated sets of
stages the approach also provides a clean path for migrating from one
resource manager to another, for example, when switching
infrastructure providers.
8.1. A Note on Provider-Coupling
In order for resource managers to instantiate the necessary
infrastructure (for example network) and PaaS-level structures (for
example databases), and in order to perform component artifact
deployment, infrastructure provider specific services and their
configuration parameters need to be part of stage set definitions.
The notion of stage sets does not aim to abstract from the specifcs
of the chosen target infrastructure beyond maybe reducing its
complexity by providing useful named predefined configurations (aka
"T-shirt sizes").
9. The Stage Set JSON Object
The canonical model for a Stage Set document is a JSON [RFC8259]
object.
When serialized as a JSON document, that format is identified with
the "application/vnd.ply.stageset+json" media type.
9.1. A YAML-formatted example of a stage set model
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name: myset
'product-ref': ply://acme/search
budget: '66474-gghk-88733/00'
'status-href': http://example.org/acme/search/stagesets/status
stages:
- name: dev
criticality: work
dependencyInstances:
- name: mydb
parameters:
- name: foo
value: bar
componentDeployments:
- name: searcher
artifact: myrepo.example.com/images/foo:1
dns: www.example.org
- name: prod
...
10. Delivery Fabrics
TBD: Describe delivery fabrics and their documents analog to stage
sets.
11. Extension Resource Families
This specifications defines two resource families, stage sets and
delivery fabrics.
New resource families can be defined outside of this specification as
extensions. The following SHOULD be supported by such extensions:
TBD: What can be required from extensions to allow for some generic
tools support?
12. Well Defined Execution Environment Variables
TBD Define the list of common environment variables for execution
environments
o PLY_LOC_STAGE
o PLY_LOC_REGION
o PLY_LOC_SYSTEM
o ...
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13. Example Implementations
TBD
14. Security Considerations
TBD
15. IANA Considerations
This specification defines new Internet media types [RFC6838].
15.1. application/vnd.ply.product+json
o Type name: application
o Subtype name: vnd.ply.product+json
o Required parameters: None
o Optional parameters: None; unrecognized parameters should be
ignored
o Encoding considerations: Same as [RFC8259]
o Security considerations: see Section 5 of this document
o Interoperability considerations: None
o Published specification: TBD (this document)
o Applications that use this media type: HTTP
o Fragment identifier considerations: Same as for application/json
([RFC8259])
o Additional information:
o Deprecated alias names for this type: n/a
* Magic number(s): n/a
* File extension(s): n/a
* Macintosh file type code(s): n/a
o Person and email address to contact for further information: Jan
Algermissen algermissen@acm.org [1]
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o Intended usage: COMMON
o Restrictions on usage: None.
o Author: Jan Algermissen algermissen@acm.org [2]
o Change controller: IESG
15.2. application/vnd.ply.product+yaml
TBD
15.3. application/vnd.ply.servicelist+json
TBD
15.4. application/vnd.ply.servicelist+yaml
TBD
15.5. application/vnd.ply.execenvlist+json
TBD
15.6. application/vnd.ply.execenvlist+yaml
TBD
15.7. application/vnd.ply.stageset+json
TBD
15.8. application/vnd.ply.stageset+yaml
TBD
15.9. The ply URI scheme
TBD
15.10. The service-catalog link relation
TBD
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15.11. The execenv-catalog link relation
16. References
16.1. Normative References
[RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
<https://www.rfc-editor.org/info/rfc1034>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2181] Elz, R. and R. Bush, "Clarifications to the DNS
Specification", RFC 2181, DOI 10.17487/RFC2181, July 1997,
<https://www.rfc-editor.org/info/rfc2181>.
[RFC3232] Reynolds, J., Ed., "Assigned Numbers: RFC 1700 is Replaced
by an On-line Database", RFC 3232, DOI 10.17487/RFC3232,
January 2002, <https://www.rfc-editor.org/info/rfc3232>.
[RFC6838] Freed, N., Klensin, J., and T. Hansen, "Media Type
Specifications and Registration Procedures", BCP 13,
RFC 6838, DOI 10.17487/RFC6838, January 2013,
<https://www.rfc-editor.org/info/rfc6838>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", STD 90, RFC 8259,
DOI 10.17487/RFC8259, December 2017,
<https://www.rfc-editor.org/info/rfc8259>.
16.2. Informative References
[RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for
specifying the location of services (DNS SRV)", RFC 2782,
DOI 10.17487/RFC2782, February 2000,
<https://www.rfc-editor.org/info/rfc2782>.
[RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service
Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013,
<https://www.rfc-editor.org/info/rfc6763>.
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16.3. URIs
[1] mailto:algermissen@acm.org
[2] mailto:algermissen@acm.org
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Appendix A. Acknowledgements
Thanks to TBD for their comments.
Appendix B. Implementation Notes
TBD
Author's Address
Jan Algermissen
Jan Algermissen Solutions Engineering
EMail: algermissen@acm.org
URI: http://algermissen.io
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