anomalyco/sst · error

uv build failed: %w

Error message

uv build failed: %w

What it means

runUvBuild shells out to the `uv` tool (uv build command, via runUvCommand) to build a workspace package defined in pyproject.toml. If the uv process itself fails to start or errors out (not a non-zero exit code, which produces the exit-code variant), this error wraps the exec error. The package cannot be built, so the function's dependencies cannot be assembled.

Source

Thrown at pkg/runtime/python/build.go:1480

	if cmd.OutputDir != "" {
		args = append(args, "--out-dir="+cmd.OutputDir)
	}

	args = append(args, "--no-sources")

	workingDir := cmd.PackageDir
	if workingDir == "" {
		workingDir = "."
	}

	result, err := runUvCommand(ctx, "uv", args, workingDir)
	if err != nil {
		slog.Error("UV build command failed",
			"package", cmd.PackageName,
			"command", "uv "+strings.Join(args, " "),
			"error", err)
		return fmt.Errorf("uv build failed: %w", err)
	}

	if !result.Success {
		return fmt.Errorf("uv build failed (exit code %d): %s", result.ExitCode, result.Stderr)
	}

	return nil
}

// runUvExport executes a UV export command
func runUvExport(ctx context.Context, cmd *uvExportCommand) error {
	args := []string{"export"}

	if cmd.AllPackages {
		args = append(args, "--all-packages")
	} else if cmd.PackageName != "" {
		args = append(args, "--package="+cmd.PackageName)
	}

View on GitHub (pinned to a0bd20f762)

Solutions

1. Install uv (curl -LsSf https://astral.sh/uv/install.sh | sh) and confirm `uv --version` works in the same shell/toolchain used to run the build
2. Verify the working directory for the build exists (the package dir with pyproject.toml) and contains a valid [build-system] section
3. Check that the uv binary is executable and on PATH for the process running the deploy/CI step
4. Read the wrapped error and slog output — it logs the exact `uv ...` command that failed
5. Build the package manually with `uv build` in the package directory to reproduce the underlying failure

Example fix

// before (CI)
# uv not installed in image
=> uv build failed: exec: "uv": executable file not found in $PATH
// after (Dockerfile)
RUN curl -LsSf https://astral.sh/uv/install.sh | sh
ENV PATH="/root/.local/bin:${PATH}"

# before building with SST, verify uv is available
if ! command -v uv >/dev/null 2>&1; then
  echo "uv is required but not installed"; exit 1
fi
uv --version

if err := buildPackage(ctx, cmd); err != nil {
    if strings.Contains(err.Error(), `executable file not found in $PATH`) {
        // uv missing: surface install instructions to the user
    }
    return err
}

When it happens

Trigger: buildPackage invokes runUvBuild for a workspace package and runUvCommand returns an error — typically the `uv` binary is not installed or not on PATH, the working directory is missing, or spawning the process failed (exec.ErrNotFound / permission denied).

Common situations: CI image or dev machine without uv installed; uv not on PATH for the build process (nvm/asdf version manager shims); wrong PATH in container; uv binary present but not executable.

Related errors

• uv build failed (exit code %d): %s
• UV export failed: %w
• uv pip install timed out after 15 minutes - check network co
• failed to run uv pip install: %v %s Function: %s Handler: %
• %s

AI-assisted analysis of anomalyco/sst@a0bd20f762 (2026-08-30). Data as JSON: /api/errors/947e7c420ce431d4. Report an issue: GitHub.