open-nomad/client/driver/driver.go

130 lines
3.7 KiB
Go

package driver
import (
"fmt"
"log"
"sync"
"github.com/hashicorp/nomad/client/allocdir"
"github.com/hashicorp/nomad/client/config"
"github.com/hashicorp/nomad/client/driver/environment"
"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{
"docker": NewDockerDriver,
"exec": NewExecDriver,
"java": NewJavaDriver,
"qemu": NewQemuDriver,
}
// NewDriver is used to instantiate and return a new driver
// given the name and a logger
func NewDriver(name string, ctx *DriverContext) (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(ctx)
return f, nil
}
// Factory is used to instantiate a new Driver
type Factory func(*DriverContext) 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)
}
// DriverContext is a means to inject dependencies such as loggers, configs, and
// node attributes into a Driver without having to change the Driver interface
// each time we do it. Used in conjection with Factory, above.
type DriverContext struct {
taskName string
config *config.Config
logger *log.Logger
node *structs.Node
}
// NewDriverContext initializes a new DriverContext with the specified fields.
// This enables other packages to create DriverContexts but keeps the fields
// private to the driver. If we want to change this later we can gorename all of
// the fields in DriverContext.
func NewDriverContext(taskName string, config *config.Config, node *structs.Node, logger *log.Logger) *DriverContext {
return &DriverContext{
taskName: taskName,
config: config,
node: node,
logger: logger,
}
}
// 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 contains information about the alloc directory structure.
AllocDir *allocdir.AllocDir
}
// NewExecContext is used to create a new execution context
func NewExecContext(alloc *allocdir.AllocDir) *ExecContext {
return &ExecContext{AllocDir: alloc}
}
// TaskEnvironmentVariables converts exec context and task configuration into a
// TaskEnvironment.
func TaskEnvironmentVariables(ctx *ExecContext, task *structs.Task) environment.TaskEnvironment {
env := environment.NewTaskEnivornment()
env.SetMeta(task.Meta)
if ctx.AllocDir != nil {
env.SetAllocDir(ctx.AllocDir.AllocDir)
}
if task.Resources != nil {
env.SetMemLimit(task.Resources.MemoryMB)
env.SetCpuLimit(task.Resources.CPU)
if len(task.Resources.Networks) > 0 {
network := task.Resources.Networks[0]
env.SetTaskIp(network.IP)
env.SetPorts(network.MapDynamicPorts())
}
}
return env
}