open-nomad/client/driver/driver.go

82 lines
2.2 KiB
Go

package driver
import (
"fmt"
"log"
"sync"
"github.com/hashicorp/nomad/client/config"
"github.com/hashicorp/nomad/client/fingerprint"
"github.com/hashicorp/nomad/nomad/structs"
)
// BuiltinDrivers contains the built in registered drivers
// which are available for allocation handling
var BuiltinDrivers = map[string]Factory{
"exec": NewExecDriver,
"java": NewJavaDriver,
"docker": NewDockerDriver,
}
// NewDriver is used to instantiate and return a new driver
// given the name and a logger
func NewDriver(name string, logger *log.Logger, config *config.Config) (Driver, error) {
// Lookup the factory function
factory, ok := BuiltinDrivers[name]
if !ok {
return nil, fmt.Errorf("unknown driver '%s'", name)
}
// Instantiate the driver
f := factory(logger, config)
return f, nil
}
// Factory is used to instantiate a new Driver
type Factory func(*log.Logger, *config.Config) Driver
// Driver is used for execution of tasks. This allows Nomad
// to support many pluggable implementations of task drivers.
// Examples could include LXC, Docker, Qemu, etc.
type Driver interface {
// Drivers must support the fingerprint interface for detection
fingerprint.Fingerprint
// Start is used to being task execution
Start(ctx *ExecContext, task *structs.Task) (DriverHandle, error)
// Open is used to re-open a handle to a task
Open(ctx *ExecContext, handleID string) (DriverHandle, error)
}
// DriverHandle is an opaque handle into a driver used for task
// manipulation
type DriverHandle interface {
// Returns an opaque handle that can be used to re-open the handle
ID() string
// WaitCh is used to return a channel used wait for task completion
WaitCh() chan error
// Update is used to update the task if possible
Update(task *structs.Task) error
// Kill is used to stop the task
Kill() error
}
// ExecContext is shared between drivers within an allocation
type ExecContext struct {
sync.Mutex
// AllocDir is the directory used for storing any state
// of this allocation. It will be purged on alloc destroy.
AllocDir string
}
// NewExecContext is used to create a new execution context
func NewExecContext() *ExecContext {
ctx := &ExecContext{}
return ctx
}