139 lines
3.9 KiB
Go
139 lines
3.9 KiB
Go
package driver
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import (
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"fmt"
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"log"
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"strings"
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"sync"
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"github.com/hashicorp/nomad/client/config"
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"github.com/hashicorp/nomad/client/fingerprint"
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"github.com/hashicorp/nomad/nomad/structs"
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)
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// BuiltinDrivers contains the built in registered drivers
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// which are available for allocation handling
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var BuiltinDrivers = map[string]Factory{
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"docker": NewDockerDriver,
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"exec": NewExecDriver,
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"java": NewJavaDriver,
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"qemu": NewQemuDriver,
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}
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// NewDriver is used to instantiate and return a new driver
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// given the name and a logger
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func NewDriver(name string, ctx *DriverContext) (Driver, error) {
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// Lookup the factory function
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factory, ok := BuiltinDrivers[name]
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if !ok {
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return nil, fmt.Errorf("unknown driver '%s'", name)
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}
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// Instantiate the driver
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f := factory(ctx)
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return f, nil
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}
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// Factory is used to instantiate a new Driver
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type Factory func(*DriverContext) Driver
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// Driver is used for execution of tasks. This allows Nomad
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// to support many pluggable implementations of task drivers.
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// Examples could include LXC, Docker, Qemu, etc.
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type Driver interface {
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// Drivers must support the fingerprint interface for detection
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fingerprint.Fingerprint
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// Start is used to being task execution
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Start(ctx *ExecContext, task *structs.Task) (DriverHandle, error)
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// Open is used to re-open a handle to a task
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Open(ctx *ExecContext, handleID string) (DriverHandle, error)
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}
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// DriverContext is a means to inject dependencies such as loggers, configs, and
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// node attributes into a Driver without having to change the Driver interface
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// each time we do it. Used in conjection with Factory, above.
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type DriverContext struct {
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config *config.Config
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logger *log.Logger
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node *structs.Node
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}
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// NewDriverContext initializes a new DriverContext with the specified fields.
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// This enables other packages to create DriverContexts but keeps the fields
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// private to the driver. If we want to change this later we can gorename all of
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// the fields in DriverContext.
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func NewDriverContext(config *config.Config, node *structs.Node, logger *log.Logger) *DriverContext {
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return &DriverContext{
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config: config,
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node: node,
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logger: logger,
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}
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}
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// DriverHandle is an opaque handle into a driver used for task
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// manipulation
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type DriverHandle interface {
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// Returns an opaque handle that can be used to re-open the handle
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ID() string
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// WaitCh is used to return a channel used wait for task completion
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WaitCh() chan error
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// Update is used to update the task if possible
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Update(task *structs.Task) error
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// Kill is used to stop the task
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Kill() error
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}
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// ExecContext is shared between drivers within an allocation
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type ExecContext struct {
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sync.Mutex
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// AllocDir is the directory used for storing any state
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// of this allocation. It will be purged on alloc destroy.
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AllocDir string
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}
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// NewExecContext is used to create a new execution context
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func NewExecContext() *ExecContext {
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ctx := &ExecContext{}
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return ctx
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}
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// PopulateEnvironment converts exec context and task configuration into
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// environment variables so they can be passed along to a driver.
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//
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// The output is a list of strings with NAME=value pairs.
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func PopulateEnvironment(ctx *ExecContext, task *structs.Task) []string {
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env := []string{}
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env = append(env, fmt.Sprintf("NOMAD_ALLOC_DIR=%s", ctx.AllocDir))
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if task.Resources != nil {
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env = append(env, fmt.Sprintf("NOMAD_MEMORY_LIMIT=%d", task.Resources.MemoryMB))
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env = append(env, fmt.Sprintf("NOMAD_CPU_LIMIT=%d", task.Resources.CPU))
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if len(task.Resources.Networks) > 0 {
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network := task.Resources.Networks[0]
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// IP address for this task
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env = append(env, fmt.Sprintf("NOMAD_IP=%s", network.IP))
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// Named ports for this task
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for label, port := range network.MapDynamicPorts() {
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env = append(env, fmt.Sprintf("NOMAD_PORT_%s=%d", label, port))
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}
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}
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}
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// Meta values
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for key, value := range task.Meta {
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env = append(env, fmt.Sprintf("NOMAD_META_%s=%s", strings.ToUpper(key), value))
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}
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return env
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}
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