terraform/internal/providercache/installer_events.go

145 lines
7.3 KiB
Go

package providercache
import (
"context"
"github.com/hashicorp/terraform/addrs"
"github.com/hashicorp/terraform/internal/getproviders"
)
// InstallerEvents is a collection of function references that can be
// associated with an Installer object in order to be notified about various
// installation lifecycle events during an install operation.
//
// The set of supported events is primarily motivated by allowing ongoing
// progress reports in the UI of the command running provider installation,
// and so this only exposes information interesting to display and does not
// allow the recipient of the events to influence the ongoing process.
//
// Any of the fields may be left as nil to signal that the caller is not
// interested in the associated event. It's better to leave a field set to
// nil than to assign a do-nothing function into it because the installer
// may choose to skip preparing certain temporary data structures if it can see
// that a particular event is not used.
type InstallerEvents struct {
// The PendingProviders event is called prior to other events to give
// the recipient prior notice of the full set of distinct provider
// addresses it can expect to see mentioned in the other events.
//
// A recipient driving a UI might, for example, use this to pre-allocate
// UI space for status reports for all of the providers and then update
// those positions in-place as other events arrive.
PendingProviders func(reqs map[addrs.Provider]getproviders.VersionConstraints)
// ProviderAlreadyInstalled is called for any provider that was included
// in PendingProviders but requires no further action because a suitable
// version is already present in the local provider cache directory.
//
// This event can also appear after the QueryPackages... series if
// querying determines that a version already available is the newest
// available version.
ProviderAlreadyInstalled func(provider addrs.Provider, selectedVersion getproviders.Version)
// The BuiltInProvider... family of events describe the outcome for any
// requested providers that are built in to Terraform. Only one of these
// methods will be called for each such provider, and no other method
// will be called for them except that they are included in the
// aggregate PendingProviders map.
//
// The "Available" event reports that the requested builtin provider is
// available in this release of Terraform. The "Failure" event reports
// either that the provider is unavailable or that the request for it
// is invalid somehow.
BuiltInProviderAvailable func(provider addrs.Provider)
BuiltInProviderFailure func(provider addrs.Provider, err error)
// The QueryPackages... family of events delimit the operation of querying
// a provider source for information about available packages matching
// a particular version constraint, prior to selecting a single version
// to install.
//
// A particular install operation includes only one query per distinct
// provider, so a caller can use the provider argument as a unique
// identifier to correlate between successive events.
//
// The Begin, Success, and Failure events will each occur only once per
// distinct provider. The Retry event can occur zero or more times, and
// signals a failure that the installer is considering transient.
QueryPackagesBegin func(provider addrs.Provider, versionConstraints getproviders.VersionConstraints)
QueryPackagesSuccess func(provider addrs.Provider, selectedVersion getproviders.Version)
QueryPackagesRetry func(provider addrs.Provider, err error)
QueryPackagesFailure func(provider addrs.Provider, err error)
// The LinkFromCache... family of events delimit the operation of linking
// a selected provider package from the system-wide shared cache into the
// current configuration's local cache.
//
// This sequence occurs instead of the FetchPackage... sequence if the
// QueryPackages... sequence selects a version that is already in the
// system-wide cache, and thus we will skip fetching it from the
// originating provider source and take it from the shared cache instead.
//
// Linking should, in most cases, be a much faster operation than
// fetching. However, it could still potentially be slow in some unusual
// cases like a particularly large source package on a system where symlinks
// are impossible, or when either of the cache directories are on a network
// filesystem accessed over a slow link.
LinkFromCacheBegin func(provider addrs.Provider, version getproviders.Version, cacheRoot string)
LinkFromCacheSuccess func(provider addrs.Provider, version getproviders.Version, localDir string)
LinkFromCacheFailure func(provider addrs.Provider, version getproviders.Version, err error)
// The FetchPackage... family of events delimit the operation of retrieving
// a package from a particular source location.
//
// A particular install operation includes only one fetch per distinct
// provider, so a caller can use the provider argument as a unique
// identifier to correlate between successive events.
//
// A particular provider will either notify the LinkFromCache... events
// or the FetchPackage... events, never both in the same install operation.
//
// The Query, Begin, Success, and Failure events will each occur only once
// per distinct provider. The Retry event can occur zero or more times, and
// signals a failure that the installer is considering transient.
FetchPackageMeta func(provider addrs.Provider, version getproviders.Version) // fetching metadata prior to real download
FetchPackageBegin func(provider addrs.Provider, version getproviders.Version, location getproviders.PackageLocation)
FetchPackageSuccess func(provider addrs.Provider, version getproviders.Version, localDir string, authResult *getproviders.PackageAuthenticationResult)
FetchPackageRetry func(provider addrs.Provider, version getproviders.Version, err error)
FetchPackageFailure func(provider addrs.Provider, version getproviders.Version, err error)
// HashPackageFailure is called if the installer is unable to determine
// the hash of the contents of an installed package after installation.
// In that case, the selection will not be recorded in the target cache
// directory's lock file.
HashPackageFailure func(provider addrs.Provider, version getproviders.Version, err error)
}
// OnContext produces a context with all of the same behaviors as the given
// context except that it will additionally carry the receiving
// InstallerEvents.
//
// Passing the resulting context to an installer request will cause the
// installer to send event notifications via the callbacks inside.
func (e *InstallerEvents) OnContext(ctx context.Context) context.Context {
return context.WithValue(ctx, ctxInstallerEvents, e)
}
// installerEventsForContext looks on the given context for a registered
// InstallerEvents and returns a pointer to it if so.
//
// For caller convenience, if there is no events object attached to the
// given context this function will construct one that has all of its
// fields set to nil and return that, freeing the caller from having to
// do a nil check on the result before dereferencing it.
func installerEventsForContext(ctx context.Context) *InstallerEvents {
v := ctx.Value(ctxInstallerEvents)
if v != nil {
return v.(*InstallerEvents)
}
return &InstallerEvents{}
}
type ctxInstallerEventsType int
const ctxInstallerEvents = ctxInstallerEventsType(0)