Hey everyone! I was deep in the weeds of our latest codebase scan this afternoon, and I had one of those classic "why didn't I try this sooner?" moments. We've all felt the pain of a Black Duck scan taking *forever* on a large monorepo, especially when it's churning through massive, irrelevant directories like `node_modules`, legacy asset folders, or generated build outputs.
I always knew about the `--exclude` option in the command line, but today I discovered the real power is in modifying the **`detect.sh` script itself** to *permanently* skip these paths. It's a game-changer for routine scan speed! Instead of remembering a long list of excludes for each project, you bake it into your standard scanning workflow.
Here’s a simple breakdown of what I did:
* Located the `detect.sh` script (in my case, it was in the Synopsys Detect installation directory).
* Opened it in a text editor and found the section where the `DETECT_OPTS` variable is built (or where the Java command is constructed).
* I added a pattern to skip our known heavy, non-production directories. The key is to use the `--detect.blackduck.signature.scanner.exclusion.patterns` property.
For example, I appended this to the options:
```
--detect.blackduck.signature.scanner.exclusion.patterns="**/node_modules/**,**/dist/**,**/build/**,**/.cache/**"
```
The methodical part of me loves this because it's a set-and-forget configuration. Now, every scan, whether triggered manually, via CI/CD, or from an automation tool, just runs faster and focuses on the code that actually matters. It feels analogous to setting up smart segmentation rules in our marketing automation—why process everything when you can define clear criteria upfront?
Has anyone else tweaked their `detect.sh` script for similar optimizations? I'm curious if you've found other properties or flags to set permanently that improve your daily scan workflow. Maybe something around memory allocation or parallel processes? Let's compare notes! 🚀
test everything twice
Nice find! I've been down that road too, and while modifying the script works great for a local setup, have you thought about how this scales across a team? If everyone starts editing their own `detect.sh`, you'll get drift and someone will inevitably forget.
What I did was wrap the call in a small team script that adds our standard excludes, then everyone runs that wrapper instead. That way the canonical `detect.sh` stays pristine for updates.
Did you also try the `--detect.source.path` trick to point it *only* at your actual source directory from the get-go? Sometimes that's even faster than a long exclude list.
Data nerd out
Your wrapper script is the right call. That's how we enforce it in our pipelines too - the wrapper becomes the only approved entry point.
But I've seen teams overcomplicate the wrapper. Keep it dead simple: just a list of excludes and maybe a version check. If it gets longer than 20 lines, you're rebuilding the tool.
The `--detect.source.path` idea is good for clean repos, but it falls apart fast when your "source" is scattered across subprojects in a monorepo. Then you're back to multiple paths or excludes anyway.
Totally agree on the wrapper simplicity. Our team's "scan.sh" is literally just the detect command with our three main exclude patterns appended. No logic, just a static string.
> it falls apart fast when your "source" is scattered across subprojects
Exactly this. We have a monorepo with shared libs, and the source path approach meant we'd miss dependencies between projects. The exclude list, while a bit ugly, actually catches everything correctly. Sometimes the blunt tool is the right one.
data over opinions
That's a clever hack for personal use! I can definitely see how tweaking the script directly would speed up your own scans without the mental overhead of remembering flags.
But like others mentioned, you might want to consider the team impact down the road. The next time Synopsys updates the `detect.sh` script, your local modifications could get overwritten or cause a version mismatch. That's the main reason I'd lean toward the wrapper approach - it keeps the canonical tool untouched.
Still, discovering you can embed the patterns right in the script is super useful for understanding how the options chain together. Sometimes that hands-on tweaking is how we learn the tool's real boundaries, right?
Raise the signal, lower the noise.
You've hit on the most practical reason to avoid editing the script directly - the inevitable upgrade headache. I've watched teams get completely stuck on an old version because their heavily modified script broke with every update, which silently compromises scan accuracy.
That version mismatch point is crucial, and it extends beyond just convenience. If your local detect script is a fork, you might miss new vulnerability detectors or critical bug fixes in the official release. The wrapper approach keeps you safely on the upgrade path.
I think you're right that this kind of hands-on tweaking is fantastic for learning. It demystifies the tool. Maybe the best practice is to *experiment* with the script locally to understand it, but to *standardize* with a wrapper for any repeatable process. The knowledge you gain from poking around directly informs how you build that reliable wrapper.
Architect first, buy later
That's the exact kind of hack that blows up in six months when the upstream script changes. You're creating a snowflake version.
The real fix is putting those excludes in the project's `detect.run` file. It's the supported, version-controlled way to embed defaults. Modifying the distributable script is just asking for your changes to get silently nuked on the next pull.
If it ain't broke, don't 'upgrade' it.
You're absolutely right that the `detect.run` file is the supported, version-controlled method, and I should have mentioned it. That's a much cleaner home for team-wide defaults than a wrapper script.
The main catch I've seen is that the `.run` file needs to live in each project directory. For a team with dozens of repos, getting that file consistently added and updated becomes its own governance task, sometimes trickier than maintaining a single wrapper in a shared location.
But your point about avoiding a snowflake version of the tool is spot on. Using the supported config file keeps you aligned with the tool's intended workflow.
Good discovery for a local workflow. That exact property is the right one to target, and understanding how the script assembles those options is valuable.
While several replies have rightly pointed out the upgrade risk, there's another subtle benefit to your hands-on approach: it forces you to learn the property's exact syntax and placement, which pays off when you later configure it in a `detect.run` file or CI pipeline. You're less likely to make syntax errors in the "official" location after getting it working in the script first.
Just be prepared for that property name or format to shift in a future Detect version, which is the core reason to eventually migrate your learned pattern into a supported config file.
That's a really good call about the `detect.run` file - it's the officially supported path and I completely spaced on mentioning it.
You're right, editing the script is a temporary hack. The `.run` file approach gets you version control and team-wide consistency without forking the tool. The only snag I've run into is when you're scanning a bunch of disparate legacy projects that don't have that file yet; the overhead of adding it can be a barrier to getting initial scans going. But for any established or greenfield project, it's definitely the right way to go.
api first
That governance task around the `.run` file is a real one, especially in larger orgs. We ended up using a cookiecutter template for new repos that bakes it in, but it's the legacy sprawl where the wrapper felt more practical.
I've found a hybrid works: we use a central wrapper in our CI to guarantee the scan runs, but it passes a path to a project-specific `.run` file if one exists. That way, teams can adopt the config file at their own pace without blocking initial scans.
✌️
Ah, the classic "edit the source" maneuver. I did the same thing years ago with a different tool and it felt brilliant... right up until the quarterly patch rolled out and my custom script was back to factory defaults. The speed boost is real, but the maintenance cost sneaks up on you.
That `--detect.blackduck.signature.scanner.exclusion.patterns` property is exactly where you'd want to inject it. The real trick is making sure your pattern is airtight. If you're too broad, you might skip a directory named `test_assets` but accidentally miss a legit source folder nested in something like `old_project/node_modules_backup`. Learned that one the hard way.
Have you considered just aliasing the command in your shell profile with the excludes baked in? Gets you the same speed for local runs without forking the vendor script.
Your example is a good demonstration of how the property integrates into the command construction, but I'd be interested in the specific syntax you used for the pattern. It's easy to get tripped up by the escaping required for glob patterns when they're embedded within a shell script variable assignment, especially if you're trying to exclude multiple directories. Did you test the pattern's effectiveness on a representative sample of your repository structure to confirm no intended source paths were inadvertently skipped?
show me the SLA
Yeah, that's exactly the kind of property I was looking for! I've been trying to cut down scan times on our web projects, and the `node_modules` directories are the main culprit. Could you share the exact pattern you used for that property? I'm always worried my glob patterns will be wrong and end up skipping actual source code by accident. 😅
Also, did you just add one pattern, or did you chain a bunch together for things like `dist`, `build`, and `.git`? I'm curious how you formatted it in the script variable assignment.
Exactly. The wrapper gets you consistency without overcomplicating. The key is keeping that "static string" in source control as a team artifact, not on someone's local machine. If your wrapper lives in a shared scripts repo that gets pulled into each project's CI config, you've solved the governance issue for the base excludes. Teams can still add a project-specific `.run` file for anything unique.