chore: CI build times optimization (DDC caching)

.github/workflows/test-linux.yml

@@ -105,6 +105,27 @@ jobs:
           UNREAL_VERSION: ${{ inputs.unreal-version }}
         run: unzip sentry-unreal-*-engine"$UNREAL_VERSION".zip -d checkout/sample/Plugins/sentry
 
+      - name: Compute DDC cache key
+        id: ddc-cache-key
+        run: |
+          HASH="${{ hashFiles('checkout/sample/Content/**', 'checkout/sample/Config/**/*.ini', 'checkout/sample/*.uproject') }}"
+          KEY="ue-${{ inputs.unreal-version }}-linux-ddc-${HASH}"
+          echo "key=${KEY}" >> $GITHUB_OUTPUT
+          echo "DDC cache key: ${KEY}"
+
+      - name: Configure project-local DDC
+        shell: pwsh
+        run: ./checkout/scripts/configure-local-ddc.ps1 -ProjectPath checkout/sample
+
+      - name: Restore cached DDC
+        id: cache-ddc
+        uses: actions/cache/restore@v4
+        with:
+          path: checkout/sample/DerivedDataCache
+          key: ${{ steps.ddc-cache-key.outputs.key }}
+          restore-keys: |
+            ue-${{ inputs.unreal-version }}-linux-ddc
+
       - name: Set permissions for sample
         # sentry-native requires write access to sample project directory in order to initialize itself properly
         run: docker exec -w /workspace/checkout unreal chmod -R +x sample
@@ -117,7 +138,7 @@ jobs:
         run: |
           docker exec unreal bash -c "
             mkdir -p ~/.config/Unreal\ Engine/UnrealBuildTool ;
-            cp /workspace/checkout/.github/BuildConfiguration.xml ~/.config/Unreal\ Engine/UnrealBuildTool/ "            
+            cp /workspace/checkout/.github/BuildConfiguration.xml ~/.config/Unreal\ Engine/UnrealBuildTool/ "
 
       - name: Run tests
         id: run-tests
@@ -139,6 +160,7 @@ jobs:
             -platform=Linux \
             -nop4 \
             -cook \
+            -iterate \
             -build \
             -stage \
             -prereqss \
@@ -154,6 +176,13 @@ jobs:
             -NoSplash \
             -NullRHI          
 
+      - name: Save DDC to cache
+        if: ${{ success() && steps.cache-ddc.outputs.cache-hit != 'true' }}
+        uses: actions/cache/save@v4
+        with:
+          path: checkout/sample/DerivedDataCache
+          key: ${{ steps.ddc-cache-key.outputs.key }}
+
       - name: Collect sample test info
         if: ${{ always() && steps.run-tests.outcome == 'failure' }}
         uses: actions/upload-artifact@v4

.github/workflows/test-windows.yml

@@ -52,6 +52,27 @@ jobs:
           New-Item -ItemType Directory -Path "$env:WORKSPACE_PATH\checkout\sample\Plugins\sentry" -Force
           Expand-Archive -Path "sentry-unreal-*-engine$env:UNREAL_VERSION.zip" -DestinationPath "$env:WORKSPACE_PATH\checkout\sample\Plugins\sentry" -Force
 
+      - name: Compute DDC cache key
+        id: ddc-cache-key
+        run: |
+          $hash = "${{ hashFiles('checkout/sample/Content/**', 'checkout/sample/Config/**/*.ini', 'checkout/sample/*.uproject') }}"
+          $key = "ue-${{ inputs.unreal-version }}-win64-ddc-${hash}"
+          echo "key=${key}" >> $env:GITHUB_OUTPUT
+          echo "DDC cache key: ${key}"
+
+      - name: Configure project-local DDC
+        shell: pwsh
+        run: ./checkout/scripts/configure-local-ddc.ps1 -ProjectPath checkout/sample
+
+      - name: Restore cached DDC
+        id: cache-ddc
+        uses: actions/cache/restore@v4
+        with:
+          path: checkout/sample/DerivedDataCache
+          key: ${{ steps.ddc-cache-key.outputs.key }}
+          restore-keys: |
+            ue-${{ inputs.unreal-version }}-win64-ddc
+
       - name: Update engine's build configuration
         run: |
           docker exec unreal powershell -Command 'New-Item -ItemType Directory -Path "$env:USERPROFILE\AppData\Roaming\Unreal Engine\UnrealBuildTool" -Force'
@@ -77,6 +98,7 @@ jobs:
             -platform=Win64 `
             -nop4 `
             -cook `
+            -iterate `
             -build `
             -stage `
             -prereqss `
@@ -91,6 +113,13 @@ jobs:
             -NoSplash `
             -NullRHI
 
+      - name: Save DDC to cache
+        if: ${{ success() && steps.cache-ddc.outputs.cache-hit != 'true' }}
+        uses: actions/cache/save@v4
+        with:
+          path: checkout/sample/DerivedDataCache
+          key: ${{ steps.ddc-cache-key.outputs.key }}
+
       - name: Collect sample test info
         if: ${{ always() && steps.run-tests.outcome == 'failure' }}
         uses: actions/upload-artifact@v4

scripts/configure-local-ddc.ps1

@@ -0,0 +1,51 @@
+#!/usr/bin/env pwsh
+<#
+.SYNOPSIS
+    Configures Unreal Engine to use project-local Derived Data Cache (DDC).
+
+.DESCRIPTION
+    This script modifies the project's DefaultEngine.ini to add DDC configuration
+    that forces Unreal to store the DDC within the project directory instead of
+    the user's home directory. This enables DDC caching in CI environments.
+
+.PARAMETER ProjectPath
+    Path to the Unreal project directory containing Config/DefaultEngine.ini
+
+.EXAMPLE
+    ./configure-local-ddc.ps1 -ProjectPath "sample"
+#>
+
+param(
+    [Parameter(Mandatory=$true)]
+    [string]$ProjectPath
+)
+
+$ErrorActionPreference = "Stop"
+
+$configPath = Join-Path $ProjectPath "Config/DefaultEngine.ini"
+
+if (-not (Test-Path $configPath)) {
+    Write-Error "DefaultEngine.ini not found at: $configPath"
+    exit 1
+}
+
+Write-Host "Configuring project-local DDC for: $ProjectPath"
+
+$ddcConfig = @"
+
+[InstalledDerivedDataBackendGraph]
+MinimumDaysToKeepFile=7
+Root=(Type=KeyLength, Length=120, Inner=AsyncPut)
+AsyncPut=(Type=AsyncPut, Inner=Hierarchy)
+Hierarchy=(Type=Hierarchical, Inner=Boot, Inner=Pak, Inner=EnginePak, Inner=Local, Inner=Shared)
+Boot=(Type=Boot, Filename="%GAMEDIR%DerivedDataCache/Boot.ddc", MaxCacheSize=512)
+Local=(Type=FileSystem, ReadOnly=false, Clean=false, Flush=false, PurgeTransient=true, DeleteUnused=true, UnusedFileAge=34, FoldersToClean=-1, Path="%GAMEDIR%DerivedDataCache", EnvPathOverride=UE-LocalDataCachePath, EditorOverrideSetting=LocalDerivedDataCache)
+Shared=(Type=FileSystem, ReadOnly=false, Clean=false, Flush=false, DeleteUnused=true, UnusedFileAge=10, FoldersToClean=-1, Path="%GAMEDIR%DerivedDataCache/Shared", EnvPathOverride=UE-SharedDataCachePath, EditorOverrideSetting=SharedDerivedDataCache, CommandLineOverride=SharedDataCachePath)
+Pak=(Type=ReadPak, Filename="%GAMEDIR%DerivedDataCache/DDC.ddp")
+EnginePak=(Type=ReadPak, Filename="%ENGINEDIR%DerivedDataCache/Compressed.ddp")
+"@
+
+Add-Content -Path $configPath -Value $ddcConfig
+
+Write-Host "✓ DDC configuration added to $configPath"
+Write-Host "  DDC will be stored at: <ProjectDir>/DerivedDataCache/"