ci: backport of conditional system tests configuration (#6758)

We backport the changes to the system tests GitHub action configuration
to get its benefits on lower release branches, since the jobs are now
marked as required on PRs.

## Checklist

- [x] Change(s) are motivated and described in the PR description.
- [x] Testing strategy is described if automated tests are not included
in the PR.
- [x] Risk is outlined (performance impact, potential for breakage,
maintainability, etc).
- [x] Change is maintainable (easy to change, telemetry, documentation).
- [x] [Library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
are followed. If no release note is required, add label
`changelog/no-changelog`.
- [x] Documentation is included (in-code, generated user docs, [public
corp docs](https://github.com/DataDog/documentation/)).
- [x] Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist

- [ ] Title is accurate.
- [ ] No unnecessary changes are introduced.
- [ ] Description motivates each change.
- [ ] Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes unless absolutely necessary.
- [ ] Testing strategy adequately addresses listed risk(s).
- [ ] Change is maintainable (easy to change, telemetry, documentation).
- [ ] Release note makes sense to a user of the library.
- [ ] Reviewer has explicitly acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment.
- [ ] Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)
- [ ] If this PR touches code that signs or publishes builds or
packages, or handles credentials of any kind, I've requested a review
from `@DataDog/security-design-and-guidance`.
- [ ] This PR doesn't touch any of that.

Author: P403n1x87

.github/workflows/system-tests.yml

@@ -2,13 +2,32 @@ name: System Tests
 
 on:
   push:
+    branches:
+      - 0.x
+      - 1.x
+  pull_request:
   workflow_dispatch: {}
   schedule:
     - cron: '00 04 * * 2-6'
 
 jobs:
+  needs-run:
+    runs-on: ubuntu-latest
+    outputs:
+      outcome: ${{ steps.run_needed.outcome }}
+    steps:
+      - uses: actions/checkout@v3
+      - id: run_needed
+        name: Check if run is needed
+        run:  |
+          git fetch origin ${{ github.event.pull_request.base.sha }}
+          export PATHS=$(git diff --name-only HEAD ${{ github.event.pull_request.base.sha }})
+          python -c "import os,sys,fnmatch;sys.exit(not bool([_ for pattern in {'ddtrace/*', 'setup*', 'pyproject.toml', '.github/workflows/system-tests.yml'} for _ in fnmatch.filter(os.environ['PATHS'].splitlines(), pattern)]))"
+        continue-on-error: true
+
   system-tests:
     runs-on: ubuntu-latest
+    needs: needs-run
     strategy:
       matrix:
         include:
@@ -25,115 +44,146 @@ jobs:
       DD_API_KEY: 1234567890abcdef1234567890abcdef
     steps:
       - name: Setup python 3.9
+        if: needs.needs-run.outputs.outcome == 'success'
         uses: actions/setup-python@v4
         with:
           python-version: '3.9'
 
       - name: Checkout system tests
+        if: needs.needs-run.outputs.outcome == 'success'
         uses: actions/checkout@v3
         with:
           repository: 'DataDog/system-tests'
 
       - name: Checkout dd-trace-py
+        if: needs.needs-run.outputs.outcome == 'success'
         uses: actions/checkout@v3
         with:
           path: 'binaries/dd-trace-py'
           fetch-depth: 0
 
       - name: Build
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./build.sh
 
       - name: Run
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh
 
       - name: Run REMOTE_CONFIG_MOCKED_BACKEND_ASM_FEATURES
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh REMOTE_CONFIG_MOCKED_BACKEND_ASM_FEATURES
 
       - name: Run REMOTE_CONFIG_MOCKED_BACKEND_LIVE_DEBUGGING
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh REMOTE_CONFIG_MOCKED_BACKEND_LIVE_DEBUGGING
 
       - name: Run REMOTE_CONFIG_MOCKED_BACKEND_ASM_DD
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh REMOTE_CONFIG_MOCKED_BACKEND_ASM_DD
 
       - name: Run APPSEC_MISSING_RULES
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh APPSEC_MISSING_RULES
 
       - name: Run APPSEC_CUSTOM_RULES
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh APPSEC_CUSTOM_RULES
 
       - name: Run APPSEC_CORRUPTED_RULES
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh APPSEC_CORRUPTED_RULES
 
       - name: Run APPSEC_RULES_MONITORING_WITH_ERRORS
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh APPSEC_RULES_MONITORING_WITH_ERRORS
 
       - name: Run APPSEC_BLOCKING
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh APPSEC_BLOCKING
 
       - name: Run APPSEC_DISABLED
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh APPSEC_DISABLED
 
       - name: Run APPSEC_LOW_WAF_TIMEOUT
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh APPSEC_LOW_WAF_TIMEOUT
 
       - name: Run APPSEC_CUSTOM_OBFUSCATION
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh APPSEC_CUSTOM_OBFUSCATION
 
       - name: Run APPSEC_RATE_LIMITER
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh APPSEC_RATE_LIMITER
 
       - name: Run APPSEC_BLOCKING_FULL_DENYLIST
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh APPSEC_BLOCKING_FULL_DENYLIST
 
       - name: Run APPSEC_REQUEST_BLOCKING
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh APPSEC_REQUEST_BLOCKING
 
       - name: Run APPSEC_RUNTIME_ACTIVATION
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh APPSEC_RUNTIME_ACTIVATION
 
       - name: Run APPSEC_WAF_TELEMETRY
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh APPSEC_WAF_TELEMETRY
 
       - name: Run SAMPLING
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh SAMPLING
 
       # even on failures, we want to have artifact to be able to investigate
       # The compress step speed up a lot the upload artifact process
       - name: Compress artifact
-        if: ${{ always() }}  
+        if: needs.needs-run.outputs.outcome == 'success'
         run: tar -czvf artifact.tar.gz $(ls | grep logs)
 
       - name: Upload artifact
         uses: actions/upload-artifact@v3
-        if: ${{ always() }}
+        if: needs.needs-run.outputs.outcome == 'success'
         with:
           name: logs_${{ matrix.weblog-variant }}
           path: artifact.tar.gz
 
   parametric:
     runs-on: ubuntu-latest
+    needs: needs-run
     env:
       TEST_LIBRARY: python
       PYTHON_DDTRACE_PACKAGE: git+https://github.com/Datadog/dd-trace-py.git@${{ github.sha }}
     steps:
       - name: Checkout system tests
+        if: needs.needs-run.outputs.outcome == 'success'
         uses: actions/checkout@v3
         with:
           repository: 'DataDog/system-tests'
+
       - uses: actions/setup-python@v4
+        if: needs.needs-run.outputs.outcome == 'success'
         with:
           python-version: '3.9'
+
       - name: Build
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./build.sh -i runner
+
       - name: Run
+        if: needs.needs-run.outputs.outcome == 'success'
         run: ./run.sh PARAMETRIC
 
       - name: Compress artifact
-        if: ${{ always() }}  
+        if: needs.needs-run.outputs.outcome == 'success'
         run: tar -czvf artifact.tar.gz $(ls | grep logs)
+
       - name: Upload artifact
         uses: actions/upload-artifact@v3
-        if: ${{ always() }}
+        if: needs.needs-run.outputs.outcome == 'success'
         with:
           name: logs_parametric
           path: artifact.tar.gz