fix: build manifest of both builds succeed plus more (#8729)

### **PR Type**
Enhancement


___

### **Description**
- Split PR image builds by architecture

- Unify Dockerfile for both builds

- Improve build cache isolation per arch

- Gate final job on both builds success


___

### Diagram Walkthrough


```mermaid
flowchart LR
  A["build_pr_image_amd64"] -- "produces amd64 image" --> C["build"]
  B["build_pr_image_arm64"] -- "produces arm64 image" --> C
  C -- "runs only if both succeed" --> D["post-build steps"]
```



<details> <summary><h3> File Walkthrough</h3></summary>

<table><thead><tr><th></th><th align="left">Relevant
files</th></tr></thead><tbody><tr><td><strong>Enhancement</strong></td><td><table>
<tr>
  <td>
    <details>
<summary><strong>build-pr-image.yml</strong><dd><code>Split and harden
PR image build workflow</code>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; </dd></summary>
<hr>

.github/workflows/build-pr-image.yml

<ul><li>Rename jobs per arch: amd64/arm64<br> <li> Use single Dockerfile
path for both<br> <li> Add arch-scoped cache keys and prefixes<br> <li>
Make final job depend on both success</ul>


</details>


  </td>
<td><a
href="https://github.com/openobserve/openobserve/pull/8729/files#diff-ebeabab3ec6b3ad90cc66cb9c0d9f2ad72c7ec6116e30e9801241b46992742d6">+15/-22</a>&nbsp;
</td>

</tr>

<tr>
  <td>
    <details>
<summary><strong>Dockerfile.pr</strong><dd><code>Add unified runtime
Dockerfile for PR builds</code>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </dd></summary>
<hr>

deploy/build/Dockerfile.pr

<ul><li>Add Debian slim runtime base<br> <li> Install required runtime
packages<br> <li> Copy binary and init data dir<br> <li> Set default
command to run service</ul>


</details>


  </td>
<td><a
href="https://github.com/openobserve/openobserve/pull/8729/files#diff-0db44a1fcb127375b96718556fd43c738708efbcaf0f83a9bffe39d4bfa95a02">[link]</a>&nbsp;
&nbsp; </td>

</tr>
</table></td></tr></tr></tbody></table>

</details>

___

---------

Co-authored-by: mmosarafO2 <mosraf@openobserve.ai>

.github/workflows/api-testing.yml

@@ -40,38 +40,58 @@ jobs:
 
       - name: Checkout git repo
         uses: actions/checkout@v5
+        with:
+          fetch-depth: 0
 
-      - name: Check if API code has changes and skip if none
+      - name: Check if API code has changes
+        id: check_changes
         run: |
-          if [[ -n "${{ github.event.before }}" ]] && ! git diff --name-only ${{ github.event.before }} ${{ github.sha }} | grep -q "^src/"; then
-            echo "API code hasn't changed, skipping unit tests"
-            exit 0
+          if [ -n "${{ github.event.before }}" ]; then
+            if git diff --name-only ${{ github.event.before }} ${{ github.sha }} | grep -qE '^src/|^Cargo\.(toml|lock)$'; then
+              echo "has_changes=true" >> $GITHUB_OUTPUT
+            else
+              echo "has_changes=false" >> $GITHUB_OUTPUT
+            fi
+          else
+            # For new branches or when before is unavailable, check against base branch
+            if git diff --name-only origin/${{ github.base_ref || 'main' }} ${{ github.sha }} | grep -qE '^src/|^Cargo\.(toml|lock)$'; then
+              echo "has_changes=true" >> $GITHUB_OUTPUT
+            else
+              echo "has_changes=false" >> $GITHUB_OUTPUT
+            fi
           fi
 
       - name: Setup Rust Toolchain
+        if: steps.check_changes.outputs.has_changes == 'true'
         uses: dtolnay/rust-toolchain@master
         with:
           toolchain: nightly-2025-07-20
 
       - name: Setup Rust Cache
+        if: steps.check_changes.outputs.has_changes == 'true'
         uses: Swatinem/rust-cache@v2
         with:
           cache-on-failure: true
+          prefix-key: api-testing
 
       - name: Install Protoc
+        if: steps.check_changes.outputs.has_changes == 'true'
         uses: arduino/setup-protoc@v3
         with:
           version: "21.12"
 
       - name: Build OpenObserve debug binary
+        if: steps.check_changes.outputs.has_changes == 'true'
         run: cargo build --features mimalloc
 
       - name: Setup Python
+        if: steps.check_changes.outputs.has_changes == 'true'
         uses: actions/setup-python@v5
         with:
           python-version: "3.11.6"
 
       - name: Setup rye
+        if: steps.check_changes.outputs.has_changes == 'true'
         uses: eifinger/setup-rye@v4
         with:
           enable-cache: true
@@ -79,19 +99,24 @@ jobs:
           version: "0.27.0"
 
       - name: Start OpenObserve
+        if: steps.check_changes.outputs.has_changes == 'true'
         run: target/debug/openobserve &
 
       - name: Wait for start
+        if: steps.check_changes.outputs.has_changes == 'true'
         run: sleep 15
 
       - name: Pin cpython
+        if: steps.check_changes.outputs.has_changes == 'true'
         run: rye pin cpython@3.11.6
         working-directory: tests/api-testing/
 
       - name: Rye sync
+        if: steps.check_changes.outputs.has_changes == 'true'
         run: rye sync
         working-directory: tests/api-testing/
 
       - name: Run tests
+        if: steps.check_changes.outputs.has_changes == 'true'
         run: rye run pytest --force-sugar
         working-directory: tests/api-testing/