Fix aspire deploy of Python apps when uv.lock doesn't exist

src/Aspire.Hosting.Python/PythonAppResourceBuilderExtensions.cs

@@ -398,6 +398,10 @@ private static IResourceBuilder<PythonAppResource> AddPythonAppCore(
                         _ => throw new InvalidOperationException($"Unsupported entrypoint type: {entrypointType}")
                     };
 
+                    // Check if uv.lock exists in the working directory
+                    var uvLockPath = Path.Combine(resource.WorkingDirectory, "uv.lock");
+                    var hasUvLock = File.Exists(uvLockPath);
+
                     var builderStage = context.Builder
                         .From($"ghcr.io/astral-sh/uv:python{pythonVersion}-bookworm-slim", "builder")
                         .EmptyLine()
@@ -406,20 +410,45 @@ private static IResourceBuilder<PythonAppResource> AddPythonAppCore(
                         .Env("UV_LINK_MODE", "copy")
                         .EmptyLine()
                         .WorkDir("/app")
-                        .EmptyLine()
-                        .Comment("Install dependencies first for better layer caching")
-                        .Comment("Uses BuildKit cache mounts to speed up repeated builds")
-                        .RunWithMounts(
-                            "uv sync --locked --no-install-project --no-dev",
-                            "type=cache,target=/root/.cache/uv",
-                            "type=bind,source=uv.lock,target=uv.lock",
-                            "type=bind,source=pyproject.toml,target=pyproject.toml")
-                        .EmptyLine()
-                        .Comment("Copy the rest of the application source and install the project")
-                        .Copy(".", "/app")
-                        .RunWithMounts(
-                            "uv sync --locked --no-dev",
-                            "type=cache,target=/root/.cache/uv");
+                        .EmptyLine();
+
+                    if (hasUvLock)
+                    {
+                        // If uv.lock exists, use locked mode for reproducible builds
+                        builderStage
+                            .Comment("Install dependencies first for better layer caching")
+                            .Comment("Uses BuildKit cache mounts to speed up repeated builds")
+                            .RunWithMounts(
+                                "uv sync --locked --no-install-project --no-dev",
+                                "type=cache,target=/root/.cache/uv",
+                                "type=bind,source=uv.lock,target=uv.lock",
+                                "type=bind,source=pyproject.toml,target=pyproject.toml")
+                            .EmptyLine()
+                            .Comment("Copy the rest of the application source and install the project")
+                            .Copy(".", "/app")
+                            .RunWithMounts(
+                                "uv sync --locked --no-dev",
+                                "type=cache,target=/root/.cache/uv");
+                    }
+                    else
+                    {
+                        // If uv.lock doesn't exist, copy pyproject.toml and generate lock file
+                        builderStage
+                            .Comment("Copy pyproject.toml to install dependencies")
+                            .Copy("pyproject.toml", "/app/")
+                            .EmptyLine()
+                            .Comment("Install dependencies and generate lock file")
+                            .Comment("Uses BuildKit cache mount to speed up repeated builds")
+                            .RunWithMounts(
+                                "uv sync --no-install-project --no-dev",
+                                "type=cache,target=/root/.cache/uv")
+                            .EmptyLine()
+                            .Comment("Copy the rest of the application source and install the project")
+                            .Copy(".", "/app")
+                            .RunWithMounts(
+                                "uv sync --no-dev",
+                                "type=cache,target=/root/.cache/uv");
+                    }
 
                     var runtimeBuilder = context.Builder
                         .From($"python:{pythonVersion}-slim-bookworm", "app")

tests/Aspire.Hosting.Python.Tests/AddPythonAppTests.cs

@@ -999,6 +999,76 @@ await Verify(scriptDockerfileContent)
             .AppendContentAsFile(executableDockerfileContent);
     }
 
+    [Fact]
+    public async Task WithUvEnvironment_GeneratesDockerfileInPublishMode_WithoutUvLock()
+    {
+        using var sourceDir = new TempDirectory();
+        using var outputDir = new TempDirectory();
+        var projectDirectory = sourceDir.Path;
+
+        // Create a UV-based Python project with pyproject.toml but NO uv.lock
+        var pyprojectContent = """
+            [project]
+            name = "test-app"
+            version = "0.1.0"
+            requires-python = ">=3.12"
+            dependencies = []
+
+            [build-system]
+            requires = ["hatchling"]
+            build-backend = "hatchling.build"
+            """;
+
+        var scriptContent = """
+            print("Hello from UV project!")
+            """;
+
+        File.WriteAllText(Path.Combine(projectDirectory, "pyproject.toml"), pyprojectContent);
+        // Note: NO uv.lock file created
+        File.WriteAllText(Path.Combine(projectDirectory, "main.py"), scriptContent);
+
+        var manifestPath = Path.Combine(projectDirectory, "aspire-manifest.json");
+
+        using var builder = TestDistributedApplicationBuilder.Create(DistributedApplicationOperation.Publish, publisher: "manifest", outputPath: outputDir.Path);
+
+        // Add Python resources with different entrypoint types
+        builder.AddPythonScript("script-app", projectDirectory, "main.py")
+            .WithUvEnvironment();
+
+        builder.AddPythonModule("module-app", projectDirectory, "mymodule")
+            .WithUvEnvironment();
+
+        builder.AddPythonExecutable("executable-app", projectDirectory, "pytest")
+            .WithUvEnvironment();
+
+        var app = builder.Build();
+
+        app.Run();
+
+        // Verify that Dockerfiles were generated for each entrypoint type
+        var scriptDockerfilePath = Path.Combine(outputDir.Path, "script-app.Dockerfile");
+        Assert.True(File.Exists(scriptDockerfilePath), "Dockerfile should be generated for script entrypoint");
+
+        var moduleDockerfilePath = Path.Combine(outputDir.Path, "module-app.Dockerfile");
+        Assert.True(File.Exists(moduleDockerfilePath), "Dockerfile should be generated for module entrypoint");
+
+        var executableDockerfilePath = Path.Combine(outputDir.Path, "executable-app.Dockerfile");
+        Assert.True(File.Exists(executableDockerfilePath), "Dockerfile should be generated for executable entrypoint");
+
+        var scriptDockerfileContent = File.ReadAllText(scriptDockerfilePath);
+        var moduleDockerfileContent = File.ReadAllText(moduleDockerfilePath);
+        var executableDockerfileContent = File.ReadAllText(executableDockerfilePath);
+
+        // Verify the Dockerfiles don't use --locked flag
+        Assert.DoesNotContain("--locked", scriptDockerfileContent);
+        Assert.DoesNotContain("--locked", moduleDockerfileContent);
+        Assert.DoesNotContain("--locked", executableDockerfileContent);
+
+        await Verify(scriptDockerfileContent)
+            .AppendContentAsFile(moduleDockerfileContent)
+            .AppendContentAsFile(executableDockerfileContent);
+    }
+
     [Fact]
     public async Task WithVSCodeDebugSupport_RemovesScriptArgumentForScriptEntrypoint()
     {

tests/Aspire.Hosting.Python.Tests/Snapshots/AddPythonAppTests.WithUvEnvironment_GeneratesDockerfileInPublishMode_WithoutUvLock#00.verified.txt

@@ -0,0 +1,46 @@
+FROM ghcr.io/astral-sh/uv:python3.12-bookworm-slim AS builder
+
+# Enable bytecode compilation and copy mode for the virtual environment
+ENV UV_COMPILE_BYTECODE=1
+ENV UV_LINK_MODE=copy
+
+WORKDIR /app
+
+# Copy pyproject.toml to install dependencies
+COPY pyproject.toml /app/
+
+# Install dependencies and generate lock file
+# Uses BuildKit cache mount to speed up repeated builds
+RUN --mount=type=cache,target=/root/.cache/uv \
+    uv sync --no-install-project --no-dev
+
+# Copy the rest of the application source and install the project
+COPY . /app
+RUN --mount=type=cache,target=/root/.cache/uv \
+    uv sync --no-dev
+
+FROM python:3.12-slim-bookworm AS app
+
+# ------------------------------
+# 🚀 Runtime stage
+# ------------------------------
+# Create non-root user for security
+RUN groupadd --system --gid 999 appuser && useradd --system --gid 999 --uid 999 --create-home appuser
+
+# Copy the application and virtual environment from builder
+COPY --from=builder --chown=appuser:appuser /app /app
+
+# Add virtual environment to PATH and set VIRTUAL_ENV
+ENV PATH=/app/.venv/bin:${PATH}
+ENV VIRTUAL_ENV=/app/.venv
+ENV PYTHONDONTWRITEBYTECODE=1
+ENV PYTHONUNBUFFERED=1
+
+# Use the non-root user to run the application
+USER appuser
+
+# Set working directory
+WORKDIR /app
+
+# Run the application
+ENTRYPOINT ["python","main.py"]

tests/Aspire.Hosting.Python.Tests/Snapshots/AddPythonAppTests.WithUvEnvironment_GeneratesDockerfileInPublishMode_WithoutUvLock#01.verified.txt

@@ -0,0 +1,46 @@
+FROM ghcr.io/astral-sh/uv:python3.12-bookworm-slim AS builder
+
+# Enable bytecode compilation and copy mode for the virtual environment
+ENV UV_COMPILE_BYTECODE=1
+ENV UV_LINK_MODE=copy
+
+WORKDIR /app
+
+# Copy pyproject.toml to install dependencies
+COPY pyproject.toml /app/
+
+# Install dependencies and generate lock file
+# Uses BuildKit cache mount to speed up repeated builds
+RUN --mount=type=cache,target=/root/.cache/uv \
+    uv sync --no-install-project --no-dev
+
+# Copy the rest of the application source and install the project
+COPY . /app
+RUN --mount=type=cache,target=/root/.cache/uv \
+    uv sync --no-dev
+
+FROM python:3.12-slim-bookworm AS app
+
+# ------------------------------
+# 🚀 Runtime stage
+# ------------------------------
+# Create non-root user for security
+RUN groupadd --system --gid 999 appuser && useradd --system --gid 999 --uid 999 --create-home appuser
+
+# Copy the application and virtual environment from builder
+COPY --from=builder --chown=appuser:appuser /app /app
+
+# Add virtual environment to PATH and set VIRTUAL_ENV
+ENV PATH=/app/.venv/bin:${PATH}
+ENV VIRTUAL_ENV=/app/.venv
+ENV PYTHONDONTWRITEBYTECODE=1
+ENV PYTHONUNBUFFERED=1
+
+# Use the non-root user to run the application
+USER appuser
+
+# Set working directory
+WORKDIR /app
+
+# Run the application
+ENTRYPOINT ["python","-m","mymodule"]

tests/Aspire.Hosting.Python.Tests/Snapshots/AddPythonAppTests.WithUvEnvironment_GeneratesDockerfileInPublishMode_WithoutUvLock#02.verified.txt

@@ -0,0 +1,46 @@
+FROM ghcr.io/astral-sh/uv:python3.12-bookworm-slim AS builder
+
+# Enable bytecode compilation and copy mode for the virtual environment
+ENV UV_COMPILE_BYTECODE=1
+ENV UV_LINK_MODE=copy
+
+WORKDIR /app
+
+# Copy pyproject.toml to install dependencies
+COPY pyproject.toml /app/
+
+# Install dependencies and generate lock file
+# Uses BuildKit cache mount to speed up repeated builds
+RUN --mount=type=cache,target=/root/.cache/uv \
+    uv sync --no-install-project --no-dev
+
+# Copy the rest of the application source and install the project
+COPY . /app
+RUN --mount=type=cache,target=/root/.cache/uv \
+    uv sync --no-dev
+
+FROM python:3.12-slim-bookworm AS app
+
+# ------------------------------
+# 🚀 Runtime stage
+# ------------------------------
+# Create non-root user for security
+RUN groupadd --system --gid 999 appuser && useradd --system --gid 999 --uid 999 --create-home appuser
+
+# Copy the application and virtual environment from builder
+COPY --from=builder --chown=appuser:appuser /app /app
+
+# Add virtual environment to PATH and set VIRTUAL_ENV
+ENV PATH=/app/.venv/bin:${PATH}
+ENV VIRTUAL_ENV=/app/.venv
+ENV PYTHONDONTWRITEBYTECODE=1
+ENV PYTHONUNBUFFERED=1
+
+# Use the non-root user to run the application
+USER appuser
+
+# Set working directory
+WORKDIR /app
+
+# Run the application
+ENTRYPOINT ["pytest"]