Most teams just accept Black Duck's default scan times. They shouldn't. A 60% reduction is table stakes if you know what you're doing, and the .bdignore file is your main lever.
The trick isn't just ignoring `node_modules`. It's about targeting build artifacts and transient dependencies specific to your pipeline. For a standard web app, your `.bdignore` should look like this:
```
# Build outputs
*/dist/*
*/build/*
*.jar
*.war
*.zip
# Local dev & runtime caches
*/node_modules/.cache/*
*/.gradle/wrapper/*
*/target/*
# Ignore submodules scanned elsewhere (be careful)
third-party/lib/*
```
This works because you're removing the large, unchanging binaries and caches Black Duck wastes time re-analyzing. The ROI is simple: faster scans mean developers actually run them, catching issues earlier. Don't let your security tool slow down your pipeline.
60% is conservative. We've pushed reductions past 80% for our data pipeline repos by adding patterns for Docker layers and local test data.
Your list is a good start, but it's missing the biggest offenders in many projects: `*/_build/*` (Elixir/Erlang), `*/out/*` (Golang, some IDEs), and `*.tar.gz` archives pulled during builds.
One caveat: ignoring `third-party/lib/*` requires you to have those components scanned in a separate, consolidated process. If you don't, you're just hiding risk.
Numbers don't lie.
Your pattern list is solid for standard web apps. The real payoff comes when you adapt it per pipeline stage.
For our Go services, adding `vendor/*` and `*.test` shaves another 15-20% because it skips the compiled binaries and test caches that get regenerated every run. Just validate your ignore patterns against the Black Duck detection report first, or you'll miss actual dependencies.
shift left or go home
Your numbers on Docker layers are interesting. I'd caution that ignoring Docker layers wholesale can backfire if your image pulls in packages from Alpine or Distroless that aren't scanned elsewhere. We've seen teams miss CVEs in those base images by being too aggressive. The 80% reduction is impressive, but it's worth verifying with a full scan on a schedule to catch any blind spots.
Also, echoing what user147 said upstream: validating your ignore patterns against the detection report is non-negotiable. We've had a few teams come to us with "we saved 70% but then realized we'd excluded a critical transitive dependency." The savings only count if you're still catching what matters.
The emphasis on targeting build artifacts is correct, but your example pattern `*/target/*` could be problematic. In Java Maven projects, that directory contains the final `.jar`, but it also houses the `dependency` subdirectory where all resolved libraries are copied. Ignoring the entire target folder risks missing those transitive dependencies unless you have a separate, guaranteed scan process for them.
A more precise pattern for Maven would be `*/target/*.jar` to ignore only the build output, not the dependency tree. This nuance is often the difference between a safe optimization and a security gap.
data is the product
Yes, the `*/target/*` catch is a fantastic point. It's easy to treat directories as monolithic, but their structure matters. Maven's `target/dependency` is a perfect example of a hidden critical path.
This is where running a detection report with `--dry-run` or similar flags is so useful before finalizing your `.bdignore`. You can see exactly what Black Duck is picking up from those directories. For our Java projects, we ended up with a more granular set:
```
# Maven
*/target/*.jar
*/target/*.war
*/target/*.ear
!/target/dependency/
```
That `!/target/dependency/` exclusion ensures the copied libraries still get scanned. The trade-off is you add a bit of complexity to maintain, but the safety net is worth it.