Love the idea. Personally, I'd keep using the existing Camel XML DSL if possible. You can still embed it in the CRD. The operator that deploys it could inspect it and figure whats the most optimized runtime that can support the DSL. Perhaps if it's only using the restricted set of camel components supported by camel-go (https://github.com/lburgazzoli/camel-go) then is uses that. Otherwise it falls back to using camel spring boot.
For that to work I think we need the different runtime implementations to provide a way to ask them: 'hey do you support running this camel route?' Not a trivial thing to respond to, it might require a build step in there for traditional Camel runtimes. On Fri, Jul 13, 2018 at 4:32 AM Antonin Stefanutti <anto...@stefanutti.fr> wrote: > Hi Nicola, > > I love the idea. > > I just wonder whether YAML/JSON is an expressive enough format in the long > term. But as you’ve mentioned, starting simple would enable experimenting > some very interesting / promising optimisations. So it seems worth taking > that path, instead of trying to embed a complex DSL or the existing XML DSL > into the CRD. > > Definitely +1 > > > On 13 Jul 2018, at 01:30, Nicola Ferraro <ni.ferr...@gmail.com> wrote: > > > > Hi Cameleers, > > it's now passed some time since I started thinking about a new project > that > > we can begin here at Apache Camel, and I'd like to have your opinion. > > > > We've already been targeting cloud-native applications with Camel, > > especially on top of Kubernetes, that is becoming "the standard" cloud > > platform. But writing a Camel integration and running it on Kubernetes > > requires some effort: choosing the base platform (spring-boot, karaf, > > simple main?), adding health checks (actuator?), packaging a docker image > > and creating the Kubernetes resources (fabric8-maven-plugin, helm?), > > publishing the image on a docker registry, then finally deploying the > > resources on a Kubernetes cluster. > > > > The resulting integration container is then far from being optimal from a > > resource consumption point of view: it is likely that a Camel Spring-Boot > > application will require at least 200MB of RAM and also some CPU shares > > because of polling threads used by many components. > > > > In case people use a CI/CD pipeline, it will take also a long time to get > > from a code update to having a Kubernetes POD up and running. > > Apart from compilation and image push/pull time, also startup time is > often > > ~10 seconds for Camel + Spring-Boot in a container with standard limits > on > > resources, making it difficult to propose this combination for > "serverless > > integration" (this term is becoming increasingly more popular). > > > > So, my proposal is to start to investigate a "more cloud-native" approach > > to integration: *making Camel integrations first-class citizens in > > Kubernetes, and making them super fast and lightweight.* > > > > We can base the project on Kubernetes Custom Resource Definitions (CRD) > > < > https://kubernetes.io/docs/concepts/extend-kubernetes/api-extension/custom-resources/ > >, > > for example a Integration CRD and have a Kubernetes "operator" > > <https://coreos.com/operators/> taking care of: > > - Optimizing the integration that we want to run > > - Packaging in a container > > - Running it on Kubernetes > > - Managing its entire lifecycle > > > > A Kubernetes-native integration may look like: > > > > ------------------- > > kind: "Integration" > > apiVersion: "camel.apache.org/v1alpha1" > > metadata: > > name: "example" > > spec: > > replicas: 1 > > routes: > > - id: timer > > route: > > - type: endpoint > > uri: timer:tick > > - type: endpoint > > uri: log:info > > ------------------- > > > > For those who are not familiar with Kubernetes resources, this kind of > > YAML/JSON resource definitions are really common. > > The example route is embedded in the Kubernetes resource declaration and > > follows a basic "flow DSL". We may start from a basic one and evolve it > as > > new requirements arrive from the community. > > > > I've made a very simple (but working) POC here: > > https://github.com/nicolaferraro/integration-operator. > > > > This idea of a "Cloud-Native Camel" on Kubernetes (project codename can > be " > > *Kamel*", if you like it :D), will be an enabler for a lot of nice > features. > > > > For example, we can propose "Kamel" as "ideal" platform for "serverless > > integration" (I see many people reinventing the wheel out there): the > > operator can reduce resource consumption of a single integration by > > optimizing the runtime and also pause/resume integrations when they are > not > > used, that is the basic idea behind "serverless" (e.g. think to > > HTTP-triggered integrations, but not only). > > Focusing on serverless will bring more emphasis on push-based > notifications > > (webhooks, cloud events <https://cloudevents.io/>), that are rarely > used in > > Camel components, that prefer a poll based approach being it simpler to > use > > in classic deployments, but not so good in the cloud, where more > resources > > become higher direct costs for the users. > > > > The presence of the simplified DSL enables also experimenting on > "*reduced* > > subsets of Camel" implemented in languages other than Java, for example > one > > language that has a reactive approach on thread scheduling and a really > low > > memory footprint, like Go. > > > > But apart from this kind of experiments (that are valid IMO), the "Kamel" > > optimizer will have free room to choose the right platform for the > > integration that the user wants to run, including, in the future, doing > AOT > > compilation using Graal/VM (less memory, faster startup) if the features > > (components) used in the integration are supporting it (maybe we can add > > AOT compilation in the roadmap for Camel 3). > > A silly optimization: integrations starting from "timer:..." may be > > scheduled directly with Kubernetes CronJobs, so they will consume > resources > > only when actually running. > > > > Being the final integrations lightweight and being the DSL > > language-independent, we may see a increased adoption of Camel also as > > agile integration layer for not-only-java applications (both "cloud" and > > "serverless" applications). > > > > I'm the first one that would like to work on a project ilke this. I've > > worked on many Kubernetes/Openshift based applications and frameworks in > > the past years, also on operators and CRDs, and I think this way of > > redesigning integrations has a lot of potential. > > > > Integrations will not be necessarily limited to the simplified DSL, but > we > > can add extension points for scripting and even custom libraries > (although > > limiting the freedom of the optimizer). > > > > The most important thing: it may become a great project, since it's > driven > > by a great community. > > > > So, what do you think? Is it crazy enough? > > > > Nicola > > -- Hiram Chirino Engineering | Red Hat, Inc. hchir...@redhat.com | fusesource.com | redhat.com skype: hiramchirino | twitter: @hiramchirino
