We’ve heard your feedback: deploying Cadence has been a challenge, especially with limited documentation on operational aspects. So far, we’ve only provided a few docker compose files to help you get started on a development machine. However, deploying and managing Cadence at scale requires a deep understanding of underlying services, configurations and their dependencies. To address these challenges, we’re launching several initiatives to make it easier to deploy and operate Cadence clusters. These include deployment specs for common scenarios, monitoring dashboards, alerts, runbooks, and more comprehensive documentation. Introducing Cadence Kubernetes Helm Chart v0 Today, we are happy to announce the release of Cadence Kubernetes Helm Chart v0. This will be the starting point for standardizing Cadence deployments on Kubernetes. We chose Kubernetes because it's the leading compute pla ...

At Uber, we run several big multitenant Cadence clusters with hundreds of domains in each. The clusters being multi-tenant means potential noisy neighbor effects between domains. An essential aspect of avoiding this is managing how workflows interact with our infrastructure to prevent any single workflow from causing instability for the whole cluster. To this end, we are excited to introduce Workflow ID-based rate limits — a new feature designed to protect our clusters from problematic workflows and ensure stability across the board. Why Workflow ID-based Rate Limits? We already have rate limits for how many requests can be sent to a domain. However, since Cadence is sharded on the workflow ID, a user-provided input, an overused workflow with a particular id might overwhelm a shard by making too many requests. There are two main ways this happens: A user starts, or signals the ...

If you haven’t heard about Cadence, this section is for you. In a short description, Cadence is a code-driven workflow orchestration engine. The definition itself may not tell enough, so it would help splitting it into three parts: What’s a workflow? (everyone has a different definition) Why does it matter to be code-driven? Benefits of Cadence What is a Workflow? workflow.png In the simplest definition, it is “a multi-step execution”. Step here represents individual operations that are a little heavier than small in-process function calls. Although they are not limited to those: it could be a separate service call, processing a large dataset, map-reduce, thread sleep, scheduling next run, waiting for an external input, starting a sub workflow etc. It’s anything a user thinks as a single unit of logic in their code. Those steps often have dependencies among themselves. Some steps, including the very first step, might ...

NO. This change will not trigger non-deterministic error. An Activity is the smallest unit of execution for Cadence and what happens inside activities are not recorded as historical events and therefore will not be replayed. In short, this change is deterministic and it is fine to modify logic inside activities. Does changing the workflow definition trigger non-determinstic errors? YES. This is a very typical non-deterministic error. When a new workflow code change is deployed, Cadence will find if it is compatible with Cadence history. Changes to workflow definition will fail the replay process of Cadence as it finds the new workflow definition imcompatible with previous historical events. Here is a list of common workflow definition changes. Changing workflow parameter counts Changing workflow parameter types Changing workflow return types The following changes are not categorized as definition changes and therefore will not trigger non-deterministic e ...

Welcome to the latest of our regular monthly Community Spotlight updates that gives you news from in and around the Cadence community! It's been a couple of months since our last update so we have a lot of updates to share with you. Please see below for a roundup of the highlights: Proposal for Cadence Native Authentication Community member Mantas Sidlauskas has drafted a proposal around Cadence native authentication and is asking for community feedback. If you are interested in reviewing the current proposal and providing comments or feedback then please find the proposal details at the link below: Cadence Native Authentication Proposal This is a great example of how we can focus on collaborating together to find a collective solution. A big thank you to Mantas for initiating this work and we hope to see the result ...