forked from hashicorp/nomad
/
template_hook.go
158 lines (127 loc) · 3.91 KB
/
template_hook.go
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package taskrunner
import (
"context"
"fmt"
"sync"
log "github.com/hashicorp/go-hclog"
"github.com/hashicorp/nomad/client/allocrunner/interfaces"
ti "github.com/hashicorp/nomad/client/allocrunner/taskrunner/interfaces"
"github.com/hashicorp/nomad/client/allocrunner/taskrunner/template"
"github.com/hashicorp/nomad/client/config"
"github.com/hashicorp/nomad/client/taskenv"
"github.com/hashicorp/nomad/nomad/structs"
)
type templateHookConfig struct {
// logger is used to log
logger log.Logger
// lifecycle is used to interact with the task's lifecycle
lifecycle ti.TaskLifecycle
// events is used to emit events
events ti.EventEmitter
// templates is the set of templates we are managing
templates []*structs.Template
// clientConfig is the Nomad Client configuration
clientConfig *config.Config
// envBuilder is the environment variable builder for the task.
envBuilder *taskenv.Builder
}
type templateHook struct {
config *templateHookConfig
// logger is used to log
logger log.Logger
// templateManager is used to manage any consul-templates this task may have
templateManager *template.TaskTemplateManager
managerLock sync.Mutex
// vaultToken is the current Vault token
vaultToken string
// taskDir is the task directory
taskDir string
}
func newTemplateHook(config *templateHookConfig) *templateHook {
h := &templateHook{
config: config,
}
h.logger = config.logger.Named(h.Name())
return h
}
func (*templateHook) Name() string {
return "template"
}
func (h *templateHook) Prestart(ctx context.Context, req *interfaces.TaskPrestartRequest, resp *interfaces.TaskPrestartResponse) error {
h.managerLock.Lock()
defer h.managerLock.Unlock()
// If we have already run prerun before exit early.
if h.templateManager != nil {
return nil
}
// Store the current Vault token and the task directory
h.taskDir = req.TaskDir.Dir
h.vaultToken = req.VaultToken
unblockCh, err := h.newManager()
if err != nil {
return err
}
// Wait for the template to render
select {
case <-ctx.Done():
case <-unblockCh:
}
return nil
}
func (h *templateHook) newManager() (unblock chan struct{}, err error) {
unblock = make(chan struct{})
m, err := template.NewTaskTemplateManager(&template.TaskTemplateManagerConfig{
UnblockCh: unblock,
Lifecycle: h.config.lifecycle,
Events: h.config.events,
Templates: h.config.templates,
ClientConfig: h.config.clientConfig,
VaultToken: h.vaultToken,
TaskDir: h.taskDir,
EnvBuilder: h.config.envBuilder,
MaxTemplateEventRate: template.DefaultMaxTemplateEventRate,
})
if err != nil {
h.logger.Error("failed to create template manager", "error", err)
return nil, err
}
h.templateManager = m
return unblock, nil
}
func (h *templateHook) Stop(ctx context.Context, req *interfaces.TaskStopRequest, resp *interfaces.TaskStopResponse) error {
h.managerLock.Lock()
defer h.managerLock.Unlock()
// Shutdown any created template
if h.templateManager != nil {
h.templateManager.Stop()
}
return nil
}
// Handle new Vault token
func (h *templateHook) Update(ctx context.Context, req *interfaces.TaskUpdateRequest, resp *interfaces.TaskUpdateResponse) error {
h.managerLock.Lock()
defer h.managerLock.Unlock()
// Nothing to do
if h.templateManager == nil {
return nil
}
// Check if the Vault token has changed
if req.VaultToken == h.vaultToken {
return nil
} else {
h.vaultToken = req.VaultToken
}
// Shutdown the old template
h.templateManager.Stop()
h.templateManager = nil
// Create the new template
if _, err := h.newManager(); err != nil {
err := fmt.Errorf("failed to build template manager: %v", err)
h.logger.Error("failed to build template manager", "error", err)
h.config.lifecycle.Kill(context.Background(),
structs.NewTaskEvent(structs.TaskKilling).
SetFailsTask().
SetDisplayMessage(fmt.Sprintf("Template update %v", err)))
}
return nil
}