open-nomad/client/fingerprint/fingerprint.go
Chelsea Holland Komlo b8e8064835 code review fixup
2018-01-31 18:34:03 -05:00

110 lines
3.4 KiB
Go

package fingerprint
import (
"fmt"
"log"
"sort"
"time"
cstructs "github.com/hashicorp/nomad/client/structs"
)
// EmptyDuration is to be used by fingerprinters that are not periodic.
const (
EmptyDuration = time.Duration(0)
// TightenNetworkTimeoutsConfig is a config key that can be used during
// tests to tighten the timeouts for fingerprinters that make network calls.
TightenNetworkTimeoutsConfig = "test.tighten_network_timeouts"
)
func init() {
// Initialize the list of available fingerprinters per platform. Each
// platform defines its own list of available fingerprinters.
initPlatformFingerprints(hostFingerprinters)
}
var (
// hostFingerprinters contains the host fingerprints which are available for a
// given platform.
hostFingerprinters = map[string]Factory{
"arch": NewArchFingerprint,
"consul": NewConsulFingerprint,
"cpu": NewCPUFingerprint,
"host": NewHostFingerprint,
"memory": NewMemoryFingerprint,
"network": NewNetworkFingerprint,
"nomad": NewNomadFingerprint,
"signal": NewSignalFingerprint,
"storage": NewStorageFingerprint,
"vault": NewVaultFingerprint,
}
// envFingerprinters contains the fingerprints that are environment specific.
// This should run after the host fingerprinters as they may override specific
// node resources with more detailed information.
envFingerprinters = map[string]Factory{
"env_aws": NewEnvAWSFingerprint,
"env_gce": NewEnvGCEFingerprint,
}
)
// BuiltinFingerprints is a slice containing the key names of all registered
// fingerprints available. The order of this slice should be preserved when
// fingerprinting.
func BuiltinFingerprints() []string {
fingerprints := make([]string, 0, len(hostFingerprinters))
for k := range hostFingerprinters {
fingerprints = append(fingerprints, k)
}
sort.Strings(fingerprints)
for k := range envFingerprinters {
fingerprints = append(fingerprints, k)
}
return fingerprints
}
// NewFingerprint is used to instantiate and return a new fingerprint
// given the name and a logger
func NewFingerprint(name string, logger *log.Logger) (Fingerprint, error) {
// Lookup the factory function
factory, ok := hostFingerprinters[name]
if !ok {
factory, ok = envFingerprinters[name]
if !ok {
return nil, fmt.Errorf("unknown fingerprint '%s'", name)
}
}
// Instantiate the fingerprint
f := factory(logger)
return f, nil
}
// Factory is used to instantiate a new Fingerprint
type Factory func(*log.Logger) Fingerprint
// Fingerprint is used for doing "fingerprinting" of the
// host to automatically determine attributes, resources,
// and metadata about it. Each of these is a heuristic, and
// many of them can be applied on a particular host.
type Fingerprint interface {
// Fingerprint is used to update properties of the Node,
// and returns a diff of updated node attributes and a potential error.
Fingerprint(*cstructs.FingerprintRequest, *cstructs.FingerprintResponse) error
// Periodic is a mechanism for the fingerprinter to indicate that it should
// be run periodically. The return value is a boolean indicating if it
// should be periodic, and if true, a duration.
Periodic() (bool, time.Duration)
}
// StaticFingerprinter can be embedded in a struct that has a Fingerprint method
// to make it non-periodic.
type StaticFingerprinter struct{}
func (s *StaticFingerprinter) Periodic() (bool, time.Duration) {
return false, EmptyDuration
}