forked from LaconicNetwork/kompose
83 lines
3.2 KiB
Markdown
83 lines
3.2 KiB
Markdown
# Architecture and Internal Design
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* TOC
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{:toc}
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`kompose` has 3 stages: Loader, Transformer and Outputter. Each Stage should have well defined interface so it is easy to write new Loader, Transformer or Outputters and plug it in. Currently only Loader and Transformer interfaces are defined.
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## Loader
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Loader reads input file (now `kompose` supports [Docker Compose](https://docs.docker.com/compose) v1, v2 and [Docker Distributed Application Bundle](https://blog.docker.com/2016/06/docker-app-bundle/) file) and converts it to KomposeObject.
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Loader is represented by a Loader interface:
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```go
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type Loader interface {
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LoadFile(file string) kobject.KomposeObject
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}
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```
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Every loader “implementation” should be placed into `kompose/pkg/loader` (like compose & bundle). More input formats will be supported in future. You can take a look for more details at:
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* [kompose/pkg/loader](https://github.com/kubernetes/kompose/tree/master/pkg/loader)
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* [kompose/pkg/loader/bundle](https://github.com/kubernetes/kompose/tree/master/pkg/loader/bundle)
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* [kompose/pkg/loader/compose](https://github.com/kubernetes/kompose/tree/master/pkg/loader/compose)
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## KomposeObject
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`KomposeObject` is Kompose internal representation of all containers loaded from input file. First version of `KomposeObject` looks like this (source: [kobject.go](https://github.com/kubernetes/kompose/blob/master/pkg/kobject/kobject.go)):
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```go
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// KomposeObject holds the generic struct of Kompose transformation
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type KomposeObject struct {
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ServiceConfigs map[string]ServiceConfig
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}
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// ServiceConfig holds the basic struct of a container
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type ServiceConfig struct {
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ContainerName string
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Image string
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Environment []EnvVar
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Port []Ports
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Command []string
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WorkingDir string
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Args []string
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Volumes []string
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Network []string
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Labels map[string]string
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Annotations map[string]string
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CPUSet string
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CPUShares int64
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CPUQuota int64
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CapAdd []string
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CapDrop []string
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Entrypoint []string
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Expose []string
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Privileged bool
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Restart string
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User string
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}
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```
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## Transformer
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Transformer takes KomposeObject and converts it to target/output format (at this moment, there are sets of kubernetes/openshift objects). Similar to `Loader`, Transformer is represented by a Transformer interface:
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```go
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type Transformer interface {
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Transform(kobject.KomposeObject, kobject.ConvertOptions) []runtime.Object
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}
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```
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If you wish to add more providers which contain different kind of objects, transformer would be the place to look into. At this moment Kompose supports Kubernetes (by default) and Openshift providers. More details at:
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* [kompose/pkg/transformer](https://github.com/kubernetes/kompose/tree/master/pkg/transformer)
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* [kompose/pkg/transformer/kubernetes](https://github.com/kubernetes/kompose/tree/master/pkg/transformer/kubernetes)
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* [kompose/pkg/transformer/openshift](https://github.com/kubernetes/kompose/tree/master/pkg/transformer/openshift)
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## Outputter
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Outputter takes Transformer result and executes given action. For example action can be displaying result to stdout or directly deploying artifacts to Kubernetes/OpenShift.
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