Software Engineering, Project Management, and Effectiveness
When I review an approach, I find it helpful to distill it to a simple frame so I can get a bird's-eye view. For MSF Agile, I found the most useful frame to be the workstreams and key activities. According to MSF, workstreams are simply groups of activities that flow logically together and are usually associated with a particular role. I couldn't find this view in MSF Agile, so I created one:
Inspections are a white-box technique to proactively check against specific criteria. You can integrate inspections as part of your testing process at key stages, such as design, implementation and deployment.
Design InspectionsIn a design inspection, you evaluate the key engineering decisions. This helps avoid expensive do-overs. Think of inspections as a dry-run of the design assumptions. Here’s some practices I’ve found to be effective for design inspections:
Code InspectionsIn a code inspection, you focus on the implementation. Code inspections are particularly effective for finding lower-level issues, as well as balancing trade-offs. For example, a lot of security issues are implementation level, and they require trade-off decisions. Here’s some practices I’ve found to be effective for code inspections:
Deployment InspectionsDeployment is where application meets infrastructure. Deployment inspections are particularly helpful for quality attributes such as performance, security, reliability and manageability concerns. Here’s some practices I’ve found to be effective for deployment inspections:
In the future, I'll post some more specific techniques for security and performance.
In this post, I'll focus on design, code, and deployment inspections for performance. Inspections are a white-box technique to proactively check against specific criteria. You can integrate inspections at key stages in your life cycle, such as design, implementation and deployment.
Keys to Effective Inspections
Performance FrameThe Performance Frame is a set of categories that helps you organize and focus on performance issues. You can use the frame to organize principles, practices, patterns and anti-patterns. The categories are also effective for organizing sets of questions to use during inspections. By using the categories in the frame, you can chunk up your inspections. The frame is also good for finding low-hanging fruit.
Performance Design InspectionsPerformance design inspections focus on the key engineering decisions and strategies. Basically, these are the decisions that have cascading impact and that you don't want to make up on the fly. For example, your candidate strategies for caching per user and application-wide data, paging records, and exception management would be good to inspect. Effective performance design inspections include analyzing the deployment and infrastructure, walking the performance frame, and doing a layer-by-layer analysis. Question-driven inspections are good because they help surface key risks and they encourage curiosity.
While there are underlying principles and patterns that you can consider, you need to temper your choices with prototypes, tests and feedback. Performance decisions are usually trade-offs with other quality attributes, such as security, extensibility, or maintainability. Performance Modeling helps you make trade-off decisions by focusing on scenarios, goals and constraints.
For more information, see Architecture and Design Review of a .NET Application for Performance and Scalability and Performance Modeling.
Performance Code InspectionsPerformance code inspections focus on evaluating coding techniques and design choices. The goal is to identify potential performance and scalability issues before the code is in production. The key to effective performance code inspections is to use a profiler to localize and find the hot spots. The anti-pattern is blindly trying to optimize the code. Again, a question-driven technique used in conjunction with measuring is key.
For more information, see Performance Code Inspection.
Performance Deployment InspectionsPerformance deployment inspections focus on tuning the configuration for your deployment scenario. To do this, you need to have measurements and runtime data to know where to look. This includes simulating your deployment environment and workload. You also need to know the knobs and switches that influence the runtime behavior. You also need to be bounded by your quality of service requirements so you know when you're done. Scenarios help you prioritize.
My Related Posts
Inspections are among my favorite tools for improving security. I like them because they’re so effective and efficient. Here’s why:
Bottom line -- you can identify, catalog and share security criteria faster than new security issues come along.
Security FrameOur Security Frame is simply a set of categories we use to “frame” out, organize, and chunk up security threats, attacks, vulnerabilities and countermeasures, as well as principles, practices and patterns. The categories make it easy to distill and share the information in a repeatable way.
Security Design InspectionsPerforming a Security Design Inspection involves evaluating your application’s architecture and design in relation to its target deployment environment from a security perspective. You can use the Security Frame to help guide your analysis. For example, you can walk the categories (authentication, authorization, … etc.) for the application. You can also use the categories to do a layer-by-layer analysis. Design inspections are a great place to checkpoint your core strategies, as well as identify what sort of end-to-end tests you need to verify your approach.
Here's the approach in a nutshell:
For more information, see our patterns & practices Security Design Inspection Index.
Security Code InspectionsThis is truly a place where inspections shine. While static analysis will catch a lot of the low hanging fruit, manual inspection will find a lot of the important security issues that are context dependent. Because it’s a manual exercise, it’s important to set objectives, and to prioritize based on what you’re looking for. Whether you do your inspections in pairs or in groups or individually, checklists in the form of criteria or inspection questions are helpful.
For more information on Security Code Inspections, see our patterns & practices Security Code Inspection Index. For examples of “Inspection Questions”, see Security Question List: Managed Code (.NET Framework 2.0) and Security Question List: ASP.NET 2.0.” (Security Question List: ASP.NET 2.0).
Security Deployment InspectionsDeployment Inspections are particularly effective for security because this is where the rubber meets the road. In a deployment inspection, you walk the various knobs and switches that impact the security profile of your solution. This is where you check things such as accounts, shares, protocols, … etc.
The following server security categories are key when performing a security deployment inspection:
For more information, see our patterns & practices Security Deployment Inspection Index.
While I've been quiet on my blog, we've been busy behind the scenes. Here's a rundown on key things:
I'll have more to say soon.