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Releasing Code

June 20th, 2011

The Release process

The Release process defines the actions required to deliver a software product to an external customer. The external customer is any entity outside the development department. This may be a true (paying) customer, or may be another engineering department, for example Testing or Production.

The Release process is a triggered activity. The trigger events are scheduled as part of project planning. Defining a release is a project milestone which must define

  • What will be released
  • When it will be released
  • Who it will be released to

 

Release process relationships

The Release process is related to, but independent of, the Change Management, Revision Control and Build Processes.

 

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Figure 21 – Release management is related to, but independent of, the other CM practices

Change Management

Defines the modifications and/or additions to the product, the order in which the changes are incorporated.

Revision Control

Ensures the configuration of the product is controlled and reproducible.

Build Process

Defines how to build the product.

Release Process

Defines the target recipient of the product.

 

Software release stages

During development the product may be released:

  • To different standards
  • To different customers

The different releases comprise a release lifecycle, with each stage representing an improvement in product quality (Figure 22).

 

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Figure 22 – Each release type represents a different level of quality, and may be released to different customers
 
Development releases

Development releases are internal releases; usually to (independent) test. These releases are unlikely to be ‘feature-complete’; often the release represents one or more work packages (or, in the case of Agile projects, features or ‘sprints’).

It is not expected that these early releases are perfect. It is likely they have only undergone developer testing. A significant number of bugs can be expected in early releases.

Development releases may be produced at high frequency. Weekly releases would be expected at the beginning of development, possibly rising to daily as the project enters a debug phase.

Alpha and Beta

Alpha and Beta releases focus on usage and/or useability testing. Sometimes these are known as Technical Preview releases. The product may be feature-complete (or close) at this stage. Alpha/Beta releases are relatively stable and should contain no (known) critical bugs.

Alpha testing consists of simulated or actual operational testing. It is normally carried out in-house and performed by non-development users, for example internal proxy-customers (staff acting on behalf of the ‘real’ customers).

Beta testing is also operational testing. It is often performed out-house (that is, outside the control of the development organisation). It is carried out by focus groups, or specially selected users. Very often Beta releases are made available free to existing customers to use and test in their own environment.

It is important not to begin Alpha and Beta releases too early in the development cycle. Although allowing users to test the product is potentially very effective a product with many bugs (particularly in areas of key user functionality) can lead to a loss of confidence in the product that is very difficult to recover.

Production-ready releases

The term Release candidate refers to a version with the potential to be a final product. It is essentially ready to release unless fatal bugs emerge during final testing (or possibly Alpha or Beta testing). The product features all designed functions and no known critical bugs.

A Production release is very similar to a Release Candidate ( in fact, it could be argued the Production release is just the final release candidate!). Any last minute bugs fixed. The Production release represents final product quality and features, and it the release sent to Production engineering.

Change Management

June 13th, 2011

Change Management is concerned with the proposal, selection and scheduling of changes during the lifecycle of a project.

Change Management is interlinked with, but separate to, Revision Control.

Change Management is the core to controlling your development processes. Without effective Change Management the management of your project is subject to slavish adherence to a (fixed, and pre-determined) project plan, with no mechanism for dealing with inevitable changes in requirements, design, implementation or testing.

It is no surprise that Change Management is at the heart of so many Agile process, such as SCRUM.

Change Request

The core of Change Management is the Change Request (often abbreviated simply as CR) A Change Request has many different names, all meaning the same thing:

  • Change Note (CN)
  • Engineering Change (Order)
  • Engineering Change Request (ECR)
  • Action Request (AR)
  • Request For Change (RFC)

Essentially, a Change Request is a call for an adjustment to a system. Change requests typically originate from one of five sources (Dennis, Wixom, & Tegarden, 2002):

  • Bugs that must be fixed
  • System enhancement requests from users
  • Events in the development of other systems
  • Changes in underlying structure and or standards
  • Demands from senior management

 

The CR Artefact

A CR is a project artefact – that is, it is a entity that is created, worked on, stored and audited, just like every other artefact in the system. The CR represents the lifecycle of a change. As such it has a different lifecycle to other artefacts.

As an artefact the CR may (in fact, should) also be held under revision control.

The CR lifecycle is shown in Figure 19. There are three main parts to the lifecycle.

 

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Figure 19 – The Change Request is an artefact with its own unique lifecycle

 
Opening the CR

Creating a CR records that some change to the system is requested; it does imply that the work will be performed. Once created the change must be reviewed before it can be worked on. The review is performed by the Change Control Board (CCB). The CCB consists of stakeholders who will be affected by the change, and those who can decide whether the change is worth doing. At the minimum this will be the Project Manager or Team Leader; but may include a multi-disciplinary group including engineering, senior management, marketing, customer support, etc.

The CR must be assessed for impact to the project. This work should ideally be done by the CR submitter. Points considered during the assessment of a change request include:

  • Technical feasibility
  • Timescales
  • Customer expectation
  • Resource
  • Quality
  • etc.

The CR may be Accepted (Opened for working), Rejected (Infeasible or invalid) or Deferred (delayed; therefore inducing technical debt to the project)

Open CRs

Once opened project artefacts can be modified. Each artefact follows its own Configuration Item lifecycle (Figure 20). The CR records artefacts modified. Each artefact records the changes made in support of the CR.

 

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Figure 20 – Each artefact modified under the Change Request follows its own change lifecycle
 
Including the change

The completed change should be reviewed again by the CCB. The purpose of the review is to assess whether the change is valid – That is, do the modifications made to the system correctly addresses the change requested? An invalid change will be rejected for rework.

Once accepted the change can be integrated into the product.

 

Change Management is often overlooked in CM. Change Management controls precisely what is going to change in the project and when. Without Change Management a project is running on ad hoc and unrecorded decisions by the development team or project manager and runs a serious risk of heading out of control.  Although the Change Management presented here involves project artefacts (CRs) many Agile processes adopt similar principles using techniques such as Product Backlogs and Feature Lists (SCRUM), which are organised by customer priority. These mechanisms are, in effect, simple Change Management processes.

Configuration Items

May 30th, 2011

A Configuration Item (sometimes referred to as a Computer System Configuration Item, or CSCI) is an artefact (hardware and/or software) that has an end-user purpose – that is, it contributes, in some way, towards the attributes of a system or product, or the development processes followed to produce the system or product. A Configuration Item (CI) is an artefact that is treated as a self-contained unit for the purposes of identification and change control. For example:

  • Specifications
  • Design models
  • Source code
  • Make files
  • etc.

Configuration Item identification

Configuration identification is the process of identifying the attributes and procedures that define every aspect of a configuration item.

Configuration identification performs three distinct roles:

Uniquely identifying each Configuration Item.

CIs are the artefacts to be controlled under Configuration Management. Each CI must be uniquely identified by name, version (revision) and location (on the file system).

Establishing a change policy

The CI’s change policy defines how the artefact is revision controlled; and whether that control changes during the lifetime of the project.

Establishing a review policy

Ideally, every artefact should be reviewed. Configuration identification establishes how the artefact will be reviewed and when it will be reviewed.

Configuration Identification must be performed prior to establishing any revision control system. All CI attributes and policies must be recorded in the project’s CM plan.

Configuration lifecycles

Configuration lifecycles define how an artifact is checked into and out of the revision control system. The configuration lifecycle defines the ‘life’ of one particular change, as it applies to that artifact (c.f. Change Management, below). The lifecycle is typically shown as a state transition diagram.

For any real project of any complexity a number of lifecycles will be required. Also note, an artefact’s lifecycle may change through the lifetime of the project. This is defined by the artefact’s change policy.

Listed below are a number of common configuration lifecycles.

‘Archive’ lifecycle

Archive artefacts are configuration items that are simply stored in the CM system. Archive artefacts are never modified once they exist. For example, the binary (download) file for a particular release.

 

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Figure 8 – The Archive lifecycle
 
‘Basic CI’ lifecycle

The ‘Basic’ CI lifecycle (Figure 9) is for artefacts that must be archive and may be modified over time. For example, the Compiler used on the project may be updated over the course of the project’s lifetime.

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Figure 9 – the Basic lifecycle

In addition, this lifecycle is used for artefacts that have not yet been released (see Release Management, below). Such items should be stored in the project’s RCS repository (for completeness) and should have their modification history recorded but these items do not need to be subject to stringent review or quality checks before being checked in.

‘Reviewed CI’ lifecycle

A ‘Reviewed’ Configuration Item must pass a review (peer or formal) before it can be checked back in (Figure 10). For example, a Requirements Specification.

This lifecycle is sometimes known as a Document lifecycle.

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Figure 10 – The Reviewed CI (or Document) lifecycle

Any artefact that has been released from development, or originates from outside the development department should be subject to this lifecycle.

‘Software CI’ lifecycle

The Software CI lifecycle (Figure 11) is an extension to the ‘Reviewed CI’ lifecycle (above). In addition to being reviewed, a software CI should also pass Static Analysis testing; and pass Unit (component) tests; before being checked in.

 

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Figure 11 – The software item lifecycle.

The Software CI lifecycle can be implemented in environments that demand very high software quality, for example safety-critical applications.

 

To get the most out of your Revision Control System each project artefact must be defined, with its usage, review policy and, perhaps most importantly, its change policy. This information gives the developer the information needed when an artefact has to change – what is required and who must be involved. Having effective configuration identification in place also ensures that the project’s artefacts retain their quality (at whatever level that quality is set)

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