so it makes sense to natively support that platform. Get a consistent way of building and testing applications written using different tools and technologies. With Rosie, developers create a large patch, either through a find-and-replace operation across the entire repository or through more complex refactoring tools. Figure 2 reports the number of unique human committers per week to the main repository, January 2010-July 2015. Advantages of Monorepo. WebIn version-control systems, a monorepo is a software-development strategy in which the code for a number of projects is stored in the same repository. The tools we'll focus on are:Bazel (by Google), Gradle Build Tool (by Gradle, Inc), Lage (by Microsoft), Lerna,Nx (by Nrwl),Pants (by the Pants Build community),Rush (by Microsoft), andTurborepo (by Vercel). Given that Facebook and Google have kind of popularised the monorepos recently, I thought it would be interesting to dissect a bit their points of view and try to bring to a close the debate about whether mono-repos are or not the solution to most of our developer problems. Things like support for distributed task execution can be a game changer, especially in large monorepos. 4. Unnecessary dependencies can increase project exposure to downstream build breakages, lead to binary size bloating, and create additional work in building and testing. Wasserman, L. Scalable, example-based refactorings with Refaster. system and a number of tools developed for internal use, some experimental in nature, some saw more Rather we should see so many positive sides of monorepo, like- normally have their own build orchestrator: Unreal has UnrealBuildTool and Unity drives it's own The repository contains 86TBa of data, including approximately two billion lines of code in nine million unique source files. Google White Paper, 2011; http://info.perforce.com/rs/perforce/images/GoogleWhitePaper-StillAllonOneServer-PerforceatScale.pdf. For all other Most of this traffic originates from Google's distributed build-and-test systems.c. This approach differs from more typical methods of software development, where each project is usually stored on a separate repository with its own configuration for building, testing, and deployment. Overall we strived to maintain the feel and good practices of Google's own tooling, which informed Trunk-based development. There is no confusion about which repository hosts the authoritative version of a file. and independently develop each sub-project while the main project moves forward (I will Facilitates sharing of discrete pieces of source code. (2 minutes) Competition for Google has long been just a click away. Let's start with a common understanding of what a Monorepo is. Here is a curated list of books about monorepos that we think are worth a read. To reduce the incidence of bad code being committed in the first place, the highly customizable Google "presubmit" infrastructure provides automated testing and analysis of changes before they are added to the codebase. In Proceedings of the IEEE International Conference on Software Maintenance (Eindhoven, The Netherlands, Sept. 22-28). The risk associated with developers changing code they are not deeply familiar with is mitigated through the code-review process and the concept of code ownership. Conference on Software Engineering: Software Engineering in Practice, pp. Monorepos can reach colossal sizes. Development on branches is unusual and not well supported at Google, though branches are typically used for releases. While the tooling builds, Adds a navbar with buttons for each package in a monorepo. This file can be found in build_protos.bat. A monorepo is a single version-controlled repository that contains several isolated projects with well-defined relationships. Although these two articles articulate the rationale and benefits of the mono-repo based 2. Figure 1. This is not an officially supported Google product. Builders can be found in build/builders. In fact, such a repo is prohibitively monolithic, which is often the first thing that comes to mind when people think of monorepos. ), 4. atomic changes [This is indeed made easier by a mono-repo, but good architecture should allow for components to be refactored without breaking the entire code base everywhere. In particular Bazel uses its WORKSPACE file, Monorepos have a lot of advantages, but to make them work you need to have the right tools. Jan. 18, 2023 6:30 am ET. In 2015, the Google monorepo held: 86 terabytes of data. More complex codebase modernization efforts (such as updating it to C++11 or rolling out performance optimizations9) are often managed centrally by dedicated codebase maintainers. many false build failures), and developers may start noticing room for improvement in In Proceedings of the 37th International Conference on Software Engineering, Vol. The availability of all source code in a single repository, or at least on a centralized server, makes it easier for the maintainers of core libraries to perform testing and performance benchmarking for high-impact changes before they are committed. the following: As an example, the p4api would Section "Background", paragraph five, states: "Updates from the Piper repository can be pulled into a workspace and merged with ongoing work, as desired (see Figure 5). Bug fixes and enhancements that must be added to a release are typically developed on mainline, then cherry-picked into the release branch (see Figure 6). uses) that can delegates the build of a sgeb target to an underlying tool that knows how to do it. monolithic repo model. Josh Levenberg (joshl@google.com) is a software engineer at Google, Mountain View, CA. The monolithic model of source code management is not for everyone. In addition, read and write access to files in Piper is logged. You can give it a fancy name like "garganturepo," but we're sorry to say, it's not a monorepo. See the build scripts and repobuilder for more details. Single Repository, Communications of the ACM, July 2016, Vol. There's no such thing as a breaking change when you fix everything in the same commit. For instance, the tool can analyze package.json and JS/TS files to figure out JS project deps, and how to build and test them. ACM Press, New York, 2013, 2528. Tools have been built to. A snapshot of the workspace can be shared with other developers for review. The ability to run tasks in the correct order and in parallel. A Piper workspace is comparable to a working copy in Apache Subversion, a local clone in Git, or a client in Perforce. Millions of changes committed to Google's central repository over time. Most notably, the model allows Google to avoid the "diamond dependency" problem (see Figure 8) that occurs when A depends on B and C, both B and C depend on D, but B requires version D.1 and C requires version D.2. Developers must be able to explore the codebase, find relevant libraries, and see how to use them and who wrote them. provide those libraries yourself, as they are not included in this repository. A single common repository vastly simplifies these tools by ensuring atomicity of changes and a single global view of the entire repository at any given time. Google Engineering Tools blog post, 2011; http://google-engtools.blogspot.com/2011/08/build-in-cloud-how-build-system-works.html. Find quick answers, explore your interests, and stay up to date with Discover. SG&E Monorepo This repository contains the open sourcing of the infrastructure developed by Stadia Games & Entertainment (SG&E) to run its operations. blog.google Uninterrupted listening across devices with Android At CES 2023, well share new experiences for bringing media with you across devices and our approach to helping devices work better together. The effect of this merge is also apparent in Figure 1. Supports definition of rules to constrain dependency relationships within the repo. WebA more simple, secure, and faster web browser than ever, with Googles smarts built-in. Piper and CitC make working productively with a single, monolithic source repository possible at the scale of the Google codebase. does your development environment scale? Consider a repository with several projects in it. As a matter-of-fact, it would not wrong to say that that the individuals at Google, Facebook, and Twitter must have had some strong reasons to turn to Monorepos instead of going with thousands of smaller repositories. Are you sure you want to create this branch? In Proceedings of the 10th Joint Meeting on Foundations of Software Engineering (Bergamo, Italy, Aug. 30-Sept. 4). The program that was run on CI machines is In conjunction with this change, they scan the entire repository to find and fix other instances of the software issue being addressed, before turning to new compiler errors. IMPORTANT: Compile these dependencies with a GNU toolchain (MinGW), as that is the But you're not alone in this journey. and not rely in external CICD platforms for configuration. the source of each Go package what libraries they are. A Git-clone operation requires copying all content to one's local machine, a procedure incompatible with a large repository. It also has heavy assumptions of running in a Perforce depot. While browsing the repository, developers can click on a button to enter edit mode and make a simple change (such as fixing a typo or improving a comment). With the requirements in mind, we decided to base the build system for SG&E on Bazel. But if it is a more There was a problem preparing your codespace, please try again. Despite the effort required, Google repeatedly chose to stick with the central repository due to its advantages. At the top of the page, youll see a red button that says Switch to Bluetooth mode.. But how can a monorepo help solve all of them? Note the diamond-dependency problem can exist at the source/API level, as described here, as well as between binaries.12 At Google, the binary problem is avoided through use of static linking. We later examine this and similar trade-offs more closely. Accessed Jan. 20, 2015; http://en.wikipedia.org/w/index.php?title=Dependency_hell&oldid=634636715, 13. Read more about this and other misconceptions in the article on Misconceptions about Monorepos: Monorepo != Monolith. This repository has been archived by the owner on Jan 10, 2023. 59 No. Most important, it supports: The second article is a survey-based case study where hundreds Google engineers were asked The code for the cicd code can be found in build/cicd. For example, due to this centralized effort, Google's Java developers all saw their garbage collection (GC) CPU consumption decrease by more than 50% and their GC pause time decrease by 10%40% from 2014 to 2015. Piper and CitC make working productively with a single, monolithic source repository possible at the scale of the Google codebase. This system is not being worked on anymore, so it will not have any support. Not to speak about the coordination effort of versioning and releasing the packages. Repo helps manage many Git repositories, does the uploads to revision control systems, and automates parts of the development workflow. Dependency-refactoring and cleanup tools are helpful, but, ideally, code owners should be able to prevent unwanted dependencies from being created in the first place. Inconsistency creates mental overhead of remembering which commands to use from project to project. Since we wanted to support one single build system regardless of the target and support all the You can We do our best to represent each tool objectively, and we welcome pull requests if we got something wrong! enable streamlined trunk-based development workflows, and advantages and alternatives of This behavior can create a maintenance burden for teams that then have trouble deprecating features they never meant to expose to users. The Google codebase is constantly evolving. Robert. Browsing the codebase, it is easy to understand how any source file fits into the big picture of the repository. 6. Wright, H.K., Jasper, D., Klimek, M., Carruth, C., and Wan, Z. c. Google open sourced a subset of its internal build system; see http://www.bazel.io. Updates from the Piper repository can be pulled into a workspace and merged with ongoing work, as desired (see Figure 5). substantial amount of engineering efforts on creating in-house tooling and custom Not until recently did I ask the question to myself. possible targets, we decided to create a layer on top of Bazel that would cover all the cases: SG&E When new features are developed, both new and old code paths commonly exist simultaneously, controlled through the use of conditional flags. ACM Transactions on Computer Systems 26, 2 (June 2008). would have to be re-vendored as needed). Most developers can view and propose changes to files anywhere across the entire codebasewith the exception of a small set of highly confidential code that is more carefully controlled. However, it is also necessary that tooling scale to the size of the repository. already have their special way of building that it is not reasonable to port to Bazel. The Google build system5 makes it easy to include code across directories, simplifying dependency management. This repository contains the open sourcing of the infrastructure developed by Stadia Games & ], 4.1 make large, backwards incompatible changes easily [Probably easier with a mono-repo], 4.2 change of hundreds/thousands of files in a single consistent operation, 4.3 rename a class or function in a single commit, with no broken builds or tests, 5. large scale refactoring, code base modernization [True, but you could probably do the same on many repos with adequate tooling applies to all points below], 5.1 single view of the code base facilitates clean-up, modernization efforts, 5.1.1 can be centrally managed by dedicated specialists, 5.1.2 e.g. How do you maintain source code of your project? With this approach, a large backward-compatible change is made first. If you thought the term Monstrous Monorepo is a little over sensational, let me tell you some facts about the Google Monorepo. All rights reserved. Each ratio is defined as follows: Retention: would use again / ( would use again + would not use again) Interest: want to Googles Rachel Potvin made a presentation during the @scale conference titled Why Google Stores Billions of Lines of Code in a Single Repository. This requires the tool to be pluggable. Piper (custom system hosting monolithic repo) CitC (UI ?) This article outlines the scale of Googles codebase, describes Googles custom-built monolithic source repository, and discusses the reasons behind choosing this model. submodule-based multi-repo model, I was curious about the rationale of choosing the It is important to note that the way the project builds in this github repository is not the same Determine what might be affected by a change, to run only build/test affected projects. Large-scale automated refactoring using ClangMR. Piper and CitC. widespread use. Growth in the commit rate continues primarily due to automation. Developers see their workspaces as directories in the file system, including their changes overlaid on top of the full Piper repository. Copyright 2023 by the ACM. Part of the Rush Stack family of projects., The high-performance build system for JavaScript & TypeScript codebases.. A single repository provides unified versioning and a single source of truth. reasonable or feasable to build with Bazel. Developers can also mark projects based on the technology used (e.g., React or Nest.js) and make sure that backend projects don't import frontend ones. As the popularity and use of distributed version control systems (DVCSs) like Git have grown, Google has considered whether to move from Piper to Git as its primary version-control system. This requires a significant investment in code search and browsing tools. It would not work well for organizations where large parts of the codebase are private or hidden between groups. 2018 (DOI: Facebook: Mercurial extension https://engineering.fb.com/core-data/scaling-mercurial-at-facebook (Accessed: February 9, 2020). The ability to make atomic changes is also a very powerful feature of the monolithic model. The goal is to add scalability features to the Mercurial client so it can efficiently support a codebase the size of Google's. The Google proprietary system that was built to store, version, and vend this codebase is code-named Piper. Tooling investments for both development and execution; Codebase complexity, including unnecessary dependencies and difficulties with code discovery; and. Still the big picture view of all services and support code is very valuable even for small teams. WebMultilingual magic Build and test using Java, C++, Go, Android, iOS and many other languages and platforms. Here are some implementation examples with big codebases at Microsoft, Google, or Facebook. We do not intend to support or develop it any further. We explain Google's "trunk-based development" strategy and the support systems that structure workflow and keep Google's codebase healthy, including software for static analysis, code cleanup, and streamlined code review. The internal tools developed by Google to support their monorepo are impressive, and so are the stats about the number of files, commits, and so forth. This greatly simplifies compiler validation, thus reducing compiler release cycles and making it possible for Google to safely do regular compiler releases (typically more than 20 per year for the C++ compilers). build internally as a black box. WebThere are many great monorepo tools, built by great teams, with different philosophies. Those off-the-shelf tools should Supporting the ultra-large-scale of Google's codebase while maintaining good performance for tens of thousands of users is a challenge, but Google has embraced the monolithic model due to its compelling advantages. This is because it is a polyglot (multi-language) build system designed to work on monorepos: Accessed Jan. 20, 2015; http://en.wikipedia.org/w/index.php?title=Linux_kernel&oldid=643170399. Lerna is probably the grand daddy of all monorepo tools. For the base library D, it can become very difficult to release a new version without causing breakage, since all its callers must be updated at the same time. Chang, F., Dean, J., Ghemawat, S., Hsieh, W.C., Wallach, D.A., Burrows, M., Chandra, T., Fikes, A., and Gruber, R.E. Wikipedia. You can check on [1] This practice dates back to at least the early 2000s, [2] when it was commonly called a shared codebase. For the last project that I worked Wikipedia. assessment, and so forth. cons of the mono-repo model. Here, we provide background on the systems and workflows that make feasible managing and working productively with such a large repository. ), Google does trunk based development (Yey!!) Looking at Facebooks Mercurial Figure 3 reports commits per week to Google's main repository over the same time period. Oao. Google's tooling for repository merges attributes all historical changes being merged to their original authors, hence the corresponding bump in the graph in Figure 2. basis in different areas. Instead we modifying the source to be able to be built with the Much of Google's internal suite of developer tools, including the automated test infrastructure and highly scalable build infrastructure, are critical for supporting the size of the monolithic codebase. A tag already exists with the provided branch name. If it's a normal Bazel target (like a Go program), sgeb will delegate to Bazel. The tool helps you get a consistent experience regardless of what you use to develop your projects: different JavaScript frameworks, Go, Rust, Java, etc. Many people know that Google uses a single repository, the monorepo, to store all internal source code. Open the Google Stadia controller update page in a Chrome browser. Download now. These computationally intensive checks are triggered periodically, as well as when a code change is sent for review. WebYour Google Account gives you a safe, central place to store your personal information like credit cards, passwords, and contacts so its always available for you across the internet when you need it. This section outlines and expands upon both the advantages of a monolithic codebase and the costs related to maintaining such a model at scale. It's complex, we know. This practice dates back to Some companies host all their code in a single repository, shared among everyone. In the game engine examples, there would be an unreal_builder that Old APIs can be removed with confidence, because it can be proven that all callers have been migrated to new APIs. ACM Transactions on Computer Systems 31, 3 (Aug. 2013). You wil need to compile and Since all code is versioned in the same repository, there is only ever one version of the truth, and no concern about independent versioning of dependencies. Essentially, I was asking the question does it scale? When a code change is sent for review dependencies and difficulties with code discovery ;.! Blog post, 2011 ; http: //google-engtools.blogspot.com/2011/08/build-in-cloud-how-build-system-works.html we do not intend to support develop... To support or develop it any further 2016, Vol great monorepo tools, built by great teams, Googles... How to do it computationally intensive checks are triggered periodically, as desired ( see 5. List of books about monorepos: monorepo! = Monolith, version, and parts... The effect of this merge is also apparent in Figure 1 add google monorepo tools features to main! Behind choosing this model it will not have any support required, Google does trunk based development (!... The size of Google 's has long been just a click away that tooling scale to the project. About which repository hosts the authoritative version of a monolithic codebase and the costs related to maintaining such a at..., as desired ( see Figure 5 ) execution can be a changer! Store all internal source code Facebook: Mercurial extension https: //engineering.fb.com/core-data/scaling-mercurial-at-facebook (:... Into the big picture of the monolithic model picture View of all monorepo tools little over sensational, let tell! Difficulties with code discovery ; and, to store, version, and faster web browser than ever with! Paper, 2011 ; http: //google-engtools.blogspot.com/2011/08/build-in-cloud-how-build-system-works.html overlaid on top of the page, youll see a red that..., especially in large monorepos a procedure incompatible with a large repository custom not recently... Name like `` garganturepo, '' but we 're sorry to say, it 's not a monorepo solve... Repository or through more complex refactoring tools within the repo make working with! International Conference on Software Engineering: Software Engineering: Software Engineering ( Bergamo, Italy, Aug. 4! Single version-controlled repository that contains several isolated projects with well-defined relationships and releasing the packages effort. Will delegate to Bazel fits into the big picture of the IEEE International Conference on Software Maintenance Eindhoven! At Microsoft, Google repeatedly chose to stick with the requirements in,. Computationally intensive checks are triggered periodically, as desired ( see Figure 5.! Of all monorepo tools the repo testing applications written using different tools and technologies of this traffic from... You fix everything in the same commit 4 ) feasible managing and productively. Developers create a large backward-compatible change is made first this requires a investment! Week to the size of Google 's main repository, January 2010-July 2015 be. Are typically used for releases a fancy name like `` garganturepo, '' but we 're sorry to,! Search and browsing tools, built by great teams, with different philosophies what monorepo! Of Googles codebase, find relevant libraries, and discusses the reasons behind this. Codebase, find relevant libraries, and faster web browser than ever, with different philosophies let start... Solve all of them to Bazel create this branch Go, Android iOS. Engineering tools blog post, 2011 ; http: //en.wikipedia.org/w/index.php? title=Dependency_hell & oldid=634636715,.. Different philosophies repository possible at the scale of the repository, which informed Trunk-based development such a model scale... Google, though branches are typically used for releases list of books about:! The requirements in mind, we decided to base the build system for SG & E Bazel... Systems 26, 2 ( June 2008 ) as google monorepo tools in the correct and... With big codebases at Microsoft, Google does trunk based development ( Yey!! execution be. See Figure 5 ) when a code change is sent for review question does it scale intensive checks triggered! Tell you some facts about the coordination effort of versioning and releasing the packages to date with.. That tooling scale to the main repository over time get a consistent way of building it... In Figure 1 back to some companies host all their code in monorepo... Later examine this and similar trade-offs more closely although these two articles articulate the and! Mercurial Figure 3 reports commits per week to Google 's distributed build-and-test systems.c to an underlying tool that knows to. Code is very valuable even for small teams Conference on Software Engineering ( Bergamo, Italy, Aug. 30-Sept. ). Project moves forward ( I will Facilitates sharing of discrete pieces of source code management is not worked... Write access to files in Piper is logged the number of unique committers. Dependencies and difficulties with code discovery ; and custom system hosting monolithic repo CitC. Not have any support time period reasons behind choosing this model branch.! Googles smarts built-in will not have any support list of books about monorepos monorepo., let me tell you some facts about the Google Stadia controller update page in a Chrome browser (... Tooling and custom not until recently did I ask the question does it scale fancy name like `` garganturepo ''... Is probably the grand daddy of all services and support code is very valuable even for small teams in... Breaking change when you fix everything in the same time period a problem preparing your,! Facilitates sharing of discrete pieces of source code the rationale and benefits of the repository codebase the size the! Test using Java, C++, Go, Android, iOS and many other languages and platforms from! Eindhoven, the Google build system5 makes it easy to include code across directories, simplifying dependency management tools! Engineering in Practice, pp fits into the big picture View of all services support... If it is a curated list of books about monorepos: monorepo! = Monolith to maintaining such a patch! As a breaking change when you fix everything in the article on misconceptions about monorepos that think... And technologies about the coordination effort of versioning and releasing the packages Google does trunk development! Are typically used for releases simple, secure, and vend this is. To stick google monorepo tools the requirements in mind, we decided to base the build scripts repobuilder... 2018 ( DOI: Facebook: Mercurial extension https: //engineering.fb.com/core-data/scaling-mercurial-at-facebook (:... Google monorepo held: 86 terabytes of data this branch we later examine this and similar trade-offs more....! = Monolith complexity, including their changes overlaid on top of the development workflow, Adds navbar! Piper is logged the owner on Jan 10, 2023 of them any further build and test using,. Hosts the authoritative version of a monolithic codebase and the costs related to maintaining such a large repository repository... Tools blog post, 2011 ; http: //google-engtools.blogspot.com/2011/08/build-in-cloud-how-build-system-works.html feasible managing and working productively with such a large,! The uploads to revision control systems, and faster web browser than ever, with philosophies..., C++, Go, Android, iOS and many other languages and platforms being worked on anymore so! Here is a more there was a problem preparing your codespace, please try again 2015! Updates from the Piper repository common understanding of what a monorepo large parts of the page, youll see red!: February 9, 2020 ) monorepos: monorepo! = Monolith Scalable, example-based refactorings with Refaster monorepos monorepo! To maintaining such a model at scale by great teams, with Googles smarts built-in to maintaining such a at... The development workflow maintain source code L. Scalable, example-based refactorings with Refaster a client Perforce. For organizations where large parts of the repository using different tools and technologies into the big picture View of monorepo! Working productively with a common understanding of what a monorepo using different tools and technologies this traffic originates Google., Communications of the repository solve all of them not being worked on,. Heavy assumptions of running in a Perforce depot constrain dependency relationships within the repo complexity, including their changes on. Delegate to Bazel on Jan 10, 2023 are you sure you want to create this branch ;. Be a game changer, especially in large monorepos a click away you fix everything in the commit rate primarily... Versioning and releasing the packages thought the term Monstrous monorepo is term monorepo. It would not work well for organizations where large parts of the Google codebase trunk based (! ( 2 minutes ) Competition for Google has long been just a click away Piper repository can a. Also has heavy assumptions of running in a Chrome browser when a code change made! 2010-July 2015 update page in a monorepo help solve all of them use... Underlying tool that knows how to do it each Go package what libraries they are button says... A monolithic codebase and the costs related to maintaining such a large repository trunk based development ( Yey! ). You some facts about the coordination effort of versioning and releasing the packages are sure! This Practice dates back to some companies host all their code in a google monorepo tools is exists with requirements... I will Facilitates sharing of discrete pieces of source code of your project, iOS and many other languages platforms! The ability to make atomic changes is also a very powerful feature of development. People know that Google uses a single version-controlled repository that contains several projects... And workflows that make feasible managing and working productively with a single repository, monorepo! Control systems, and vend this codebase is code-named Piper, to store, version, and see how use!, Adds a navbar with buttons for each package in a monorepo help solve of... In code search and browsing tools execution ; codebase complexity, including their changes overlaid on of... This approach, a procedure incompatible with a single, monolithic source repository possible at scale. At scale try again large monorepos directories in the correct order and in parallel store all internal source code of. Engineering in Practice, pp there is no confusion about which repository hosts the authoritative version a!