What is shift left?
The shift left approach
The traditional software development lifecycle
The traditional waterfall software development lifecycle is very linear and sequential. Requirements are gathered upfront, then design and development happen, followed by extensive testing and quality assurance (QA) at the end. Any defects found during testing get passed back to the developers to fix, often causing delays. This linear method results in bugs being detected late when they are most expensive to fix.
Introducing the shift left paradigm
Shift left represents a big cultural and technological change in how software is delivered. The goal is to improve quality by validating requirements, designs, and code much earlier in the software development life cycle (SDLC). Rather than hand off completed work, shift left emphasizes collaboration across the entire process. Issues can be prevented by empowering developers to find and fix code as they write it.
How shift left works
Early involvement: Engaging from inception
Shift left means bringing testing and operations teams together with developers starting in planning and requirements gathering. Their early insights help identify potential issues when they are easiest and cheapest to address.
Continuous testing: From start to finish
In a shift left model, testing becomes an integral part of the development cycle from the very start. Instead of occurring just at the end, testing is ongoing through automation across the entire lifecycle. This provides rapid feedback on code changes.
Automation: Streamlining the process
Automating processes like code reviews, builds, testing, and deployment is essential for shift left. Manual approaches simply cannot provide the speed and efficiency needed to validate code quality from the early stages.
Collaboration: Bridging development and operations
Shift left relies heavily on increased collaboration between developers, QA, and operations teams. Cross-functional communication and transparency help everyone understand requirements and user needs.
Why shift left matters
Mitigating risks: Identifying issues sooner
Detecting vulnerabilities earlier prevents problematic code from impacting other components, reducing risk. Issues caught early are also quicker and cheaper to fix.
Cost-efficiency: Reducing post-production expenses
It is much cheaper to fix vulnerabilities during development than after launch. Each later stage in the cycle increases rework costs significantly. Finding issues in pre-production saves time and money.
Accelerating time-to-market: Speeding up development cycles
Catching defects before they delay releases allows for faster delivery of new capabilities to customers accelerating time-to-market.
Enhancing quality: Delivering superior user experiences
Testing earlier improves code quality upfront, resulting in better performing apps and happier users. Higher quality software leads to increased customer satisfaction.
Key components of a successful shift left strategy
Code reviews and static analysis: Catching issues early
Analyzing code quality early via peer code reviews and static analysis during development can identify flaws before they get buried deep in the code. This prevents defects from accumulating.
Test automation: Ensuring rigorous testing
Automated unit, integration, and functional testing enables continuous testing through all stages. This provides rapid feedback on code changes so defects can be fixed promptly.
Continuous integration and continuous deployment (CI/CD): Automating delivery
CI/CD pipelines allow teams to catch issues by automatically building, testing, and deploying code changes rapidly and frequently to surface bugs sooner.
DevOps culture: Fostering collaboration and ownership
A DevOps mindset of shared responsibility across dev, QA, and ops drives communication and transparency. This understanding not only helps meet customer needs, it reduces internal friction across teams and improves teamwork.
Implementing shift left
Cultivating a shift left culture: Changing mindsets
Driving a shift left culture requires changing attitudes to value prevention, collaboration, shared ownership, automation, and continuous improvement across the development lifecycle.
Tooling and technologies: Enabling early detection
New tools and platforms provide visibility through automation, analytics, and metrics to analyze code quality, tests, and other key indicators early and often during development.
Best practices for shift left adoption
Start early: Involve all stakeholders from the outset
Engaging QA, ops, and security from the beginning through design reviews and test planning brings diverse perspectives and insights early to prevent issues.
Establish clear testing guidelines: Defining standards
Creating organization-wide test strategies and standards around coverage, frequency, types, and environments drives consistency in shift left.
Monitor and measure: Tracking progress and results
Leveraging metrics and tools provides visibility into code quality, test effectiveness, pipeline performance, and other indicators to mature shift left efforts.
Challenges and considerations
Resistance to change: Overcoming inertia
Shifting testing left requires changes in tools, automating manual processes, and workstreams that can face cultural resistance. Planning for this is key.
Balancing speed and quality: Avoiding shortcuts
The push towards rapid delivery can negatively impact code quality and testing rigor. Teams must guard against sacrificing outcomes for speed.