README
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pkg/provisioners/application
Intention
pkg/provisioners/application is the provisioner adapter for CD-managed Helm applications. It turns a managed resource plus an application lookup function into the canonical CD driver operations needed to create, update, and delete an application instance.
This package is not a generic Helm abstraction and it is not merely a thin wrapper around the CD driver. It encodes the repository's model for:
- resolving which version of a
HelmApplicationapplies to the current managed resource - deriving a stable application identity from that resource
- translating resource scope, remote-cluster scope, and optional generator customizations into a
cd.HelmApplication - delegating the actual application lifecycle to the CD driver
Like pkg/provisioners/remotecluster, this package is tightly coupled to the context-based provisioning-scope model described in pkg/client. It expects context to carry both the managed resource and the active cluster scope that determine where the application should be installed.
Invariants And Guard Rails
- Within the current in-tree CD/application model, this is the main provisioner adapter for CD-managed Helm applications.
New(applicationGetter)requires a lookup function that resolves the effectiveHelmApplicationobject and version for the current context. The provisioner does not own application discovery itself.Provision()andDeprovision()both callinitialize()at execution time, not at construction time, so application resolution happens in a path that can return normal reconcile errors.- Application identity is derived from both sides of the relationship: the application name selected during initialization and the managed resource labels carried in context. Those resource labels are sorted deterministically so the CD-layer identity remains stable.
- Destination cluster identity comes from the active
client.ClusterContextin context. Descendants are therefore expected to run under the correct provisioning scope before this provisioner is invoked. InNamespace()overrides the application namespace explicitly. Otherwise the namespace comes from the application version, falling back todefault.WithGenerator()is the historical customization seam for adding implicit release names, parameters, values, namespace metadata, ignored-difference customizations, and lifecycle hooks around an otherwise standard application template.AllowDegraded()deliberately weakens the success condition so degraded application health is accepted for cases where that is an intentional repository policy.PreDeprovisionHookruns before application deletion andPostProvisionHookruns only after successful provisioning.- Deprovision propagates
remotecluster.BackgroundDeletionFromContext(ctx)into the CD driver's delete path so descendant cleanup can respect doomed-remote semantics.
Caveats
- This package mixes several concerns in one place: application lookup, version selection, identity derivation, template customization, lifecycle hooks, remote-scope interpretation, and CD-driver delegation.
- The package is heavily context-driven. It assumes the managed resource is already present in context and that the active cluster scope has already been set correctly. If either hidden prerequisite is missing or wrong, behavior will be wrong in ways the constructor cannot prevent.
WithGenerator()is intentionally open-ended and therefore compromise-prone. It is a plugin-styleanyplus a pile of optional interface assertions, not a clean extension model. The typed generator interfaces are useful, but the genericCustomizerhook is effectively an escape hatch and should be treated with suspicion.AllowDegraded()is not a neutral option. It encodes a policy exception that should only be used when degraded application health is genuinely acceptable for that application.PreDeprovisionHookandPostProvisionHookare operational escape hatches around the main CD lifecycle. Useful, but also evidence that some managed applications still need extra bespoke handling.getResourceID()still depends onutil.Keys()for deterministic label ordering. That is one of the remaining obstacles to deleting the now-obsolete helper inpkg/util.- This package is coupled to the CD/application model. If the old in-tree CD layer continues to shrink or is replaced, this package would likely need to be split or redesigned rather than carried forward unchanged.
Documentation
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Index ¶
- func FromContext(ctx context.Context) unikornv1.ManagableResourceInterface
- func NewContext(ctx context.Context, resource unikornv1.ManagableResourceInterface) context.Context
- type Customizer
- type GetterFunc
- type NamespaceLabeler
- type Paramterizer
- type PostProvisionHook
- type PreDeprovisionHook
- type Provisioner
- type ReleaseNamer
- type ValuesGenerator
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func FromContext ¶
func FromContext(ctx context.Context) unikornv1.ManagableResourceInterface
func NewContext ¶
Types ¶
type Customizer ¶
type Customizer interface {
Customize(version unikornv1.SemanticVersion) ([]cd.HelmApplicationField, error)
}
Customizer is a generic generator interface that implemnets raw customizations to the application template. Try to avoid using this.
type GetterFunc ¶
type GetterFunc func(ctx context.Context) (*unikornv1.HelmApplication, *unikornv1.SemanticVersion, error)
ApplicationGetter abstracts away how an application is looked up for a specific entity.
type NamespaceLabeler ¶ added in v1.4.0
type NamespaceLabeler interface {
NamespaceMetadata(ctx context.Context, version unikornv1.SemanticVersion) (map[string]string, map[string]string, error)
}
NamespaceLabeler is an interface you can implement in a generator, to give a namespace created by the CD labels and annotations.
type Paramterizer ¶
type Paramterizer interface {
Parameters(ctx context.Context, version unikornv1.SemanticVersion) (map[string]string, error)
}
Paramterizer is an interface that allows generators to supply a list of parameters to Helm. These are in addition to those defined by the application template. At present, there is nothing special about overriding, it just appends, so ensure the explicit and implicit sets don't overlap.
type PostProvisionHook ¶
PostProvisionHook is an interface that lets an application provisioner run a callback when provisioning has completed successfully.
type PreDeprovisionHook ¶ added in v0.1.87
PreDeprovisionHook is an interface that lets an application deprovisioner run a callback before deprovisioning an application e.g. to handle manual resource deletion.
type Provisioner ¶
type Provisioner struct {
// Metadata defines the application name, this directly affects
// the application what will be searched for in the application bundle
// defined in the resource. It will also be the default Application ID
// name, unless overridden by Name.
provisioners.Metadata
// contains filtered or unexported fields
}
Provisioner deploys an application that is keyed to a specific resource. For example, ArgoCD dictates that applications be installed in the same namespace, so we use the resource to define a unique set of labels that identifies that resource out of all others, and add in the application name to uniquely identify the application within that resource.
func New ¶
func New(applicationGetter GetterFunc) *Provisioner
New returns a new initialized provisioner object.
func (*Provisioner) AllowDegraded ¶
func (p *Provisioner) AllowDegraded() *Provisioner
AllowDegraded accepts a degraded status as a success for an application.
func (*Provisioner) Deprovision ¶
func (p *Provisioner) Deprovision(ctx context.Context) error
Deprovision implements the Provision interface.
func (*Provisioner) InNamespace ¶
func (p *Provisioner) InNamespace(namespace string) *Provisioner
InNamespace deploys the application into an explicit namespace.
func (*Provisioner) Provision ¶
func (p *Provisioner) Provision(ctx context.Context) error
Provision implements the Provision interface.
func (*Provisioner) WithGenerator ¶
func (p *Provisioner) WithGenerator(generator any) *Provisioner
WithGenerator registers an object that can generate implicit configuration where you cannot do it all from the default set of arguments.
type ReleaseNamer ¶
ReleaseNamer is an interface that allows generators to supply an implicit release name to Helm.
type ValuesGenerator ¶
type ValuesGenerator interface {
Values(ctx context.Context, version unikornv1.SemanticVersion) (any, error)
}
ValuesGenerator is an interface that allows generators to supply a raw values.yaml file to Helm. This accepts an object that can be marshaled to YAML.
Source Files