Bloomberg 1© 2024 Bloomberg Finance L.P. All rights reserved. Dependency Injection in C++: A Practical Guide CppCon 2024 September 18, 2024 Pete Muldoon Senior Engineering LeadBloomberg 4 Questions it8 Bloomberg Where will we be going ? • Talk will be about inserting meaningful Dependency Injection in applications • Using various DI methods to achieve functionality swapping / instrumentation (or just giving up) • Talk is rooted in a real-world system not theory9 Bloomberg Dependency Injection : 1. Decreases coupling between functionality blocks 2. Used to make a class/function independent

It’s complicated! •Unit tests •Integration tests •Fuzz testing •libFuzzer •AFL •Fault injection •Failpoint, https://www.freebsd.org/cgi/man.cgi?query=fail •Jepsen, https://github.com/jepsen-io/jepsen com/jepsen-io/jepsen Tests •A framework for distributed systems verification, with fault injection
 •Found bugs •Redis •etcd •Cassandra
 … 
 Jepsen Jepsen: How does it work? N1 N2 N3 N4 N5 Control TiDB Cluster

. 10CPP INJECTION / SECURITY BREACH CPP INJECTION / SECURITY BREACH 5 . 11CPP INJECTION / SECURITY BREACH CPP INJECTION / SECURITY BREACH 5 . 11CPP INJECTION / SECURITY BREACH CPP INJECTION / SECURITY Password='' 5 . 11CPP INJECTION / SECURITY BREACH CPP INJECTION / SECURITY BREACH CPP INJECTION CPP INJECTION SELECT * FROM Users WHERE Name='' or 1==1--' and Password='' 5 . 11CPP INJECTION / SECURITY BREACH BREACH CPP INJECTION / SECURITY BREACH CPP INJECTION CPP INJECTION SELECT * FROM Users WHERE Name='' or 1==1--' and Password='' int main() { jit<"[]{ std::cout << \""s + std::getenv("USER") + "\"; }">();

1. Dependency Injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Constructor-based Dependency Injection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Setter-based Dependency Injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Examples of Dependency Injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.2.2. Dependency Injection of Test Fixtures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 3.5.7. Dependency Injection of Test Fixtures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 Dependency Injection with SpringExtension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Spring Framework 1. Getting Started with Spring 2. Introduction to the Spring Framework Dependency Injection and Inversion of Control Framework Modules Core Container AOP and Instrumentation Messaging Data Dependency Injection Constructor-based dependency injection Constructor argument resolution Setter-based dependency injection Dependency resolution process Examples of dependency injection Dependencies Limitations and disadvantages of autowiring Excluding a bean from autowiring Method injection Lookup method injection Arbitrary method replacement Bean scopes The singleton scope The prototype scope

and started to use the term Dependency Injection. His article then continued to explain the ideas underpinning the Inversion of Control (IoC) and Dependency Injection (DI) principle. If you need a decent decent insight into IoC and DI, please do refer to said article : http://martinfowler.com/articles/injection.html. Java applications (a loose term which runs the gamut from constrained applets to full-fledged Core package is the most fundamental part of the framework and provides the IoC and Dependency Injection features. The basic concept here is the BeanFactory, which provides a sophisticated implementation

and started to use the term Dependency Injection. His article then continued to explain the ideas underpinning the Inversion of Control (IoC) and Dependency Injection (DI) principle. If you need a decent decent insight into IoC and DI, please do refer to said article : http://martinfowler.com/articles/injection.html. Java applications (a loose term which runs the gamut from constrained applets to full-fledged Core package is the most fundamental part of the framework and provides the IoC and Dependency Injection features. The basic concept here is the BeanFactory, which provides a sophisticated implementation

and started to use the term Dependency Injection. His article then continued to explain the ideas underpinning the Inversion of Control (IoC) and Dependency Injection (DI) principle. If you need a decent decent insight into IoC and DI, please do refer to said article : http://martinfowler.com/articles/injection.html. Java applications (a loose term which runs the gamut from constrained applets to full-fledged Core package is the most fundamental part of the framework and provides the IoC and Dependency Injection features. The basic concept here is the BeanFactory, which provides a sophisticated implementation

and started to use the term Dependency Injection. His article then continued to explain the ideas underpinning the Inversion of Control (IoC) and Dependency Injection (DI) principle. If you need a decent decent insight into IoC and DI, please do refer to said article : http://martinfowler.com/articles/injection.html. Java applications (a loose term which runs the gamut from constrained applets to full-fledged Core package is the most fundamental part of the framework and provides the IoC and Dependency Injection features. The basic concept here is the BeanFactory, which provides a sophisticated implementation