MSc David Spielmann
david.spielmann@unisg.ch
david-spielmann-74a10919a
0009-0004-1715-2059
DaSpielmann
davidspielmann
https://david-spielmann.ch

School of Computer Science
Torstrasse 25
9000 St. Gallen, Switzerland

I joined the Programming Group as a PhD student in May 2023. I obtained my Bachelor’s degree in Computer Science from ETH Zurich and a joint Master’s degree from ETH Zurich and EPF Lausanne with a focus on security and distributed systems. As part of my Master’s thesis, I used to examine power side-channel attacks on remotely accessible FPGAs. My current research interests encompass software engineering and security, with a particular focus on improving the reliability of Infrastructure as Code (IaC) to ensure robust and consistent cloud deployments.

Publications

1. MSR
   

   TerraDS: A Dataset for Terraform HCL Programs

   Christoph Bühler, David Spielmann, Roland Meier, Guido Salvaneschi

   In Proceedings of the IEEE/ACM 22nd International Conference on Mining Software Repositories (MSR), MSR, 2025

   Abstract PDF

   Infrastructure as Code (IaC) aims to automate infrastructure management by enabling the definition of infrastructure configurations in programs, rather than manually configuring hardware or cloud resources. Terraform is one of the most widely used IaC tools, gaining significant traction in recent years, as highlighted by its large and active user community and widespread adoption in both open-source and enterprise environments. Terraform’s code is written in the HashiCorp Configuration Language (HCL), which defines the infrastructure in a declarative manner. Despite the widespread adoption of Terraform, there is no large-scale dataset available for researchers to study IaC Terraform programs systematically. To address this gap, we present TerraDS, the first dataset of publicly available Terraform programs written in HCL. TerraDS contains the HCL code and the metadata of 67,360 open source repositories with permissive open-source licenses. The dataset includes 279,344 Terraform modules with 1,773,991 registered resources, all compiled into a reusable archive ( 335 MB).

2. TSE
   ProTI
   

   Automated Infrastructure as Code Program Testing

   Daniel Sokolowski, David Spielmann, Guido Salvaneschi

   IEEE Transactions on Software Engineering 50 (6), 2024

   Abstract PDF Supp Code Website

   Infrastructure as Code (IaC) enables efficient deployment and operation, which are crucial to releasing software quickly. As setups can be complex, developers implement IaC programs in general-purpose programming languages like TypeScript and Python, using PL-IaC solutions like Pulumi and AWS CDK. The reliability of such IaC programs is even more relevant than in traditional software because a bug in IaC impacts the whole system. Yet, even though testing is a standard development practice, it is rarely used for IaC programs. For instance, in August 2022, less than 1% of the public Pulumi IaC programs on GitHub implemented tests. Available IaC program testing techniques severely limit the development velocity or require much development effort. To solve these issues, we propose Automated Configuration Testing (ACT), a methodology to test IaC programs in many configurations quickly and with low effort. ACT automatically mocks all resource definitions in the IaC program and uses generator and oracle plugins for test generation and validation. We implement ACT in ProTI, a testing tool for Pulumi TypeScript with a type-based generator and oracle, and support for application specifications. Our evaluation with 6081 programs from GitHub and artificial benchmarks shows that ProTI can directly be applied to existing IaC programs, quickly finds bugs where current techniques are infeasible, and enables reusing existing generators and oracles thanks to its pluggable architecture.

3. MSR
   

   The PIPr Dataset of Public Infrastructure as Code Programs

   Daniel Sokolowski, David Spielmann, Guido Salvaneschi

   In Proceedings of the IEEE/ACM 21st International Conference on Mining Software Repositories, MSR, 2024

   Abstract PDF

   With Programming Languages Infrastructure as Code (PL-IaC), developers implement IaC programs in popular imperative programming languages like Python and Typescript. Such programs generate the declarative target state of the deployment, i.e., they describe what to set up, not how to set it up. Despite the popularity of PL-IaC, which has grown more than ten times from 2020 to 2023, we know little about how developers apply it and how IaC programs differ from other software. Such knowledge is essential to effectively use existing software engineering techniques and develop new ones for PL-IaC. To shed light on PL-IaC in practice, we present PIPr, the first systematic PL-IaC dataset. PIPr is based on 37712 public IaC programs on GitHub from August 2022 and includes initial analyses, assessing the programming languages, testing techniques, and licenses of the IaC programs. Beyond the metadata and analysis results of all IaC programs, PIPr contains the code of all 15504 IaC programs whose licenses permit redistribution. PIPr sets the ground for future in-depth investigations on PL-IaC in practice.

4. ICSE Companion
   ProTI
   

   Unleashing the Giants: Enabling Advanced Testing for Infrastructure as Code

   Daniel Sokolowski, David Spielmann, Guido Salvaneschi

   In Companion Proceedings of the 46th International Conference on Software Engineering, ICSE Companion, 2024

   Abstract PDF

   Infrastructure as Code (IaC) programs are written in imperative programming languages like Python or TypeScript while declaratively defining the target state of software deployments, which the IaC solution then sets up, e.g., Pulumi and AWS CDK. Through a repository mining study and analysis, we noticed that testing IaC programs poses a dilemma: current techniques are either slow and expensive or require prohibitively high development effort. To solve this issue, we introduce Automated Configuration Testing (ACT), enabling efficient testing with low development effort. ACT automates the tedious aspects of unit testing IaC programs and is extensible through a plugin system for test generators and oracles. ACT is already effective with simple type-based plugins, and leveraging existing giants, i.e., advanced test generation and oracle techniques, in new plugins will further boost its effectiveness.

5. CONFLANG
   ProTI
   

   Creed for Speed: Comprehensive Infrastructure as Code Testing

   Daniel Sokolowski, David Spielmann, Guido Salvaneschi

   Presentation at the 2nd Workshop on Configuration Languages (CONFLANG), 2023

   Abstract PDF

   With Programming Languages Infrastructure as Code (PL-IaC), developers implement imperative IaC programs in one of many general-purpose programming languages, e.g., TypeScript, Python, or Go, to declaratively describe deployments. Using these languages provides access to quality assurance techniques and tools developed for traditional software; however, programmers routinely rely on prohibitively slow integration testing – if they test at all. As a result, even simple bugs are found late, tremendously slowing down the development process.

   To improve the velocity of PL-IaC development, we propose ProTI, an automated unit testing approach that quickly tests PL-IaC programs in many different configurations. ProTI mocks all cloud resources, replacing them with pluggable oracles that validate all resources configurations and a generator for realistic test inputs. We implemented ProTI for Pulumi TypeScript with simple generator and oracle plugins. Our experience of testing with ProTI encourages the exploration of more sophisticated oracles and generators, leading to the early detection of more bugs. ProTI enables programmers to rapidly prototype, explore, and plug in new oracles and generators for efficient PL-IaC program testing.

6. SPLASH Companion
   ProTI
   

   Extensible Testing for Infrastructure as Code

   David Spielmann, Daniel Sokolowski, Guido Salvaneschi

   In Companion Proceedings of the 2023 ACM SIGPLAN International Conference on Systems, Programming, Languages, and Applications: Software for Humanity, SPLASH Companion, 2023

   Abstract PDF

   Developers automate deployments with Programming Languages Infrastructure as Code (PL-IaC) by implementing IaC programs in popular languages like TypeScript and Python. Yet, systematic testing—well established for high-velocity software development—is rarely applied to IaC programs because IaC testing techniques are either slow or require extensive development effort. To solve this dilemma, we develop ProTI, a novel IaC unit testing approach, and implement it for Pulumi TypeScript. Our preliminary experiments with simple type-based test case generators and oracles show that ProTI can find bugs reliably in a short time, often without writing any additional testing code. ProTI’s extensible plugin architecture allows combining, adopting, and experimenting with new approaches, opening the discussion about novel generators and oracles for efficient IaC testing.

7. TCHES
   

   RDS: FPGA Routing Delay Sensors for Effective Remote Power Analysis Attacks

   David Spielmann, Ognjen Glamočanin, Mirjana Stojilović

   IACR Transactions on Cryptographic Hardware and Embedded Systems 198 (2), 2023

   Abstract PDF

   State-of-the-art sensors for measuring FPGA voltage fluctuations are time-to-digital converters (TDCs). They allow detecting voltage fluctuations in the order of a few nanoseconds. The key building component of a TDC is a delay line, typically implemented as a chain of fast carry propagation multiplexers. In FPGAs, the fast carry chains are constrained to dedicated logic and routing, and need to be routed strictly vertically. In this work, we present an alternative approach to designing on-chip voltage sensors, in which the FPGA routing resources replace the carry logic. We present three variants of what we name a routing delay sensor (RDS): one vertically constrained, one horizontally constrained, and one free of any constraints. We perform a thorough experimental evaluation on both the Sakura-X side-channel evaluation board and the Alveo U200 datacenter card, to evaluate the performance of RDS sensors in the context of a remote power side-channel analysis attack. The results show that our best RDS implementation in most cases outperforms the TDC. On average, for breaking the full 128-bit key of an AES-128 cryptographic core, an adversary requires 35% fewer side-channel traces when using the RDS than when using the TDC. Besides making the attack more effective, given the absence of the placement and routing constraint, the RDS sensor is also easier to deploy.