34d4bb7ea0
* #9 Implement routes to list, get and delete execution environments. A refactoring was required to introduce the ExecutionEnvironment interface. * Fix MR comments, linting issues and bug that lead to e2e test failure * Add e2e tests * Add unit tests
382 lines
15 KiB
Go
382 lines
15 KiB
Go
package nomad
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import (
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"context"
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"errors"
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"fmt"
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nomadApi "github.com/hashicorp/nomad/api"
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"github.com/hashicorp/nomad/nomad/structs"
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"github.com/openHPI/poseidon/internal/config"
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"github.com/openHPI/poseidon/pkg/logging"
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"github.com/openHPI/poseidon/pkg/nullio"
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"io"
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"strconv"
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"time"
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)
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var (
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log = logging.GetLogger("nomad")
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ErrorExecutorCommunicationFailed = errors.New("communication with executor failed")
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ErrorEvaluation = errors.New("evaluation could not complete")
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ErrorPlacingAllocations = errors.New("failed to place all allocations")
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ErrorLoadingJob = errors.New("failed to load job")
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ErrorNoAllocatedResourcesFound = errors.New("no allocated resources found")
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)
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type AllocationProcessor func(*nomadApi.Allocation)
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// ExecutorAPI provides access to a container orchestration solution.
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type ExecutorAPI interface {
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apiQuerier
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// LoadEnvironmentJobs loads all environment jobs.
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LoadEnvironmentJobs() ([]*nomadApi.Job, error)
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// LoadRunnerJobs loads all runner jobs specific for the environment.
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LoadRunnerJobs(environmentID string) ([]*nomadApi.Job, error)
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// LoadRunnerIDs returns the IDs of all runners of the specified environment which are running and not about to
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// get stopped.
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LoadRunnerIDs(environmentID string) (runnerIds []string, err error)
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// LoadRunnerPortMappings returns the mapped ports of the runner.
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LoadRunnerPortMappings(runnerID string) ([]nomadApi.PortMapping, error)
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// RegisterRunnerJob creates a runner job based on the template job.
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// It registers the job and waits until the registration completes.
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RegisterRunnerJob(template *nomadApi.Job) error
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// MonitorEvaluation monitors the given evaluation ID.
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// It waits until the evaluation reaches one of the states complete, canceled or failed.
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// If the evaluation was not successful, an error containing the failures is returned.
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// See also https://github.com/hashicorp/nomad/blob/7d5a9ecde95c18da94c9b6ace2565afbfdd6a40d/command/monitor.go#L175
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MonitorEvaluation(evaluationID string, ctx context.Context) error
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// WatchAllocations listens on the Nomad event stream for allocation events.
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// Depending on the incoming event, any of the given function is executed.
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WatchAllocations(ctx context.Context, onNewAllocation, onDeletedAllocation AllocationProcessor) error
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// ExecuteCommand executes the given command in the allocation with the given id.
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// It writes the output of the command to stdout/stderr and reads input from stdin.
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// If tty is true, the command will run with a tty.
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ExecuteCommand(allocationID string, ctx context.Context, command []string, tty bool,
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stdin io.Reader, stdout, stderr io.Writer) (int, error)
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// MarkRunnerAsUsed marks the runner with the given ID as used. It also stores the timeout duration in the metadata.
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MarkRunnerAsUsed(runnerID string, duration int) error
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}
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// APIClient implements the ExecutorAPI interface and can be used to perform different operations on the real
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// Executor API and its return values.
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type APIClient struct {
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apiQuerier
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}
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// NewExecutorAPI creates a new api client.
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// One client is usually sufficient for the complete runtime of the API.
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func NewExecutorAPI(nomadConfig *config.Nomad) (ExecutorAPI, error) {
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client := &APIClient{apiQuerier: &nomadAPIClient{}}
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err := client.init(nomadConfig)
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return client, err
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}
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// init prepares an apiClient to be able to communicate to a provided Nomad API.
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func (a *APIClient) init(nomadConfig *config.Nomad) error {
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if err := a.apiQuerier.init(nomadConfig); err != nil {
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return fmt.Errorf("error initializing API querier: %w", err)
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}
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return nil
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}
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func (a *APIClient) LoadRunnerIDs(environmentID string) (runnerIDs []string, err error) {
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list, err := a.listJobs(environmentID)
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if err != nil {
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return nil, err
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}
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for _, jobListStub := range list {
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allocationRunning := jobListStub.JobSummary.Summary[TaskGroupName].Running > 0
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if jobListStub.Status == structs.JobStatusRunning && allocationRunning {
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runnerIDs = append(runnerIDs, jobListStub.ID)
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}
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}
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return runnerIDs, nil
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}
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func (a *APIClient) LoadRunnerPortMappings(runnerID string) ([]nomadApi.PortMapping, error) {
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alloc, err := a.apiQuerier.allocation(runnerID)
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if err != nil {
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return nil, fmt.Errorf("error querying allocation for runner %s: %w", runnerID, err)
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}
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if alloc.AllocatedResources == nil {
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return nil, ErrorNoAllocatedResourcesFound
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}
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return alloc.AllocatedResources.Shared.Ports, nil
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}
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func (a *APIClient) LoadRunnerJobs(environmentID string) ([]*nomadApi.Job, error) {
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runnerIDs, err := a.LoadRunnerIDs(environmentID)
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if err != nil {
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return []*nomadApi.Job{}, fmt.Errorf("couldn't load jobs: %w", err)
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}
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var occurredError error
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jobs := make([]*nomadApi.Job, 0, len(runnerIDs))
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for _, id := range runnerIDs {
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job, err := a.apiQuerier.job(id)
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if err != nil {
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if occurredError == nil {
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occurredError = ErrorLoadingJob
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}
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occurredError = fmt.Errorf("%w: couldn't load job info for runner %s - %v", occurredError, id, err)
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continue
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}
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jobs = append(jobs, job)
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}
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return jobs, occurredError
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}
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func (a *APIClient) MonitorEvaluation(evaluationID string, ctx context.Context) error {
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stream, err := a.apiQuerier.EvaluationStream(evaluationID, ctx)
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if err != nil {
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return fmt.Errorf("failed retrieving evaluation stream: %w", err)
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}
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// If ctx is canceled, the stream will be closed by Nomad and we exit the for loop.
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return receiveAndHandleNomadAPIEvents(stream, handleEvaluationEvent)
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}
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func (a *APIClient) WatchAllocations(ctx context.Context,
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onNewAllocation, onDeletedAllocation AllocationProcessor) error {
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startTime := time.Now().UnixNano()
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stream, err := a.AllocationStream(ctx)
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if err != nil {
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return fmt.Errorf("failed retrieving allocation stream: %w", err)
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}
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pendingAllocations := make(map[string]bool)
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handler := func(event *nomadApi.Event) (bool, error) {
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return false, handleAllocationEvent(startTime, pendingAllocations, event, onNewAllocation, onDeletedAllocation)
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}
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err = receiveAndHandleNomadAPIEvents(stream, handler)
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return err
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}
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// nomadAPIEventHandler is a function that receives a nomadApi.Event and processes it.
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// It is called by an event listening loop. For each received event, the function is called.
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// If done is true, the calling function knows that it should break out of the event listening
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// loop.
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type nomadAPIEventHandler func(event *nomadApi.Event) (done bool, err error)
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// receiveAndHandleNomadAPIEvents receives events from the Nomad event stream and calls the handler function for
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// each received event. It skips heartbeat events and returns an error if the received events contain an error.
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func receiveAndHandleNomadAPIEvents(stream <-chan *nomadApi.Events, handler nomadAPIEventHandler) error {
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// If original context is canceled, the stream will be closed by Nomad and we exit the for loop.
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for events := range stream {
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if events.IsHeartbeat() {
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continue
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}
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if err := events.Err; err != nil {
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return fmt.Errorf("error receiving events: %w", err)
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}
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for _, event := range events.Events {
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// Don't take the address of the loop variable as the underlying value might change
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eventCopy := event
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done, err := handler(&eventCopy)
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if err != nil || done {
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return err
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}
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}
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}
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return nil
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}
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// handleEvaluationEvent is a nomadAPIEventHandler that returns whether the evaluation described by the event
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// was successful.
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func handleEvaluationEvent(event *nomadApi.Event) (bool, error) {
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eval, err := event.Evaluation()
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if err != nil {
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return true, fmt.Errorf("failed to monitor evaluation: %w", err)
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}
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switch eval.Status {
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case structs.EvalStatusComplete, structs.EvalStatusCancelled, structs.EvalStatusFailed:
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return true, checkEvaluation(eval)
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}
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return false, nil
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}
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// handleAllocationEvent is a nomadAPIEventHandler that processes allocation events.
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// If a new allocation is received, onNewAllocation is called. If an allocation is deleted, onDeletedAllocation
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// is called. The pendingAllocations map is used to store allocations that are pending but not started yet. Using the
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// map the state is persisted between multiple calls of this function.
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func handleAllocationEvent(startTime int64, pendingAllocations map[string]bool, event *nomadApi.Event,
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onNewAllocation, onDeletedAllocation AllocationProcessor) error {
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if event.Type != structs.TypeAllocationUpdated {
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return nil
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}
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alloc, err := event.Allocation()
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if err != nil {
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return fmt.Errorf("failed to retrieve allocation from event: %w", err)
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} else if alloc == nil {
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return nil
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}
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// When starting the API and listening on the Nomad event stream we might get events that already
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// happened from Nomad as it seems to buffer them for a certain duration.
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// Ignore old events here.
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if alloc.ModifyTime < startTime {
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return nil
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}
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if alloc.ClientStatus == structs.AllocClientStatusRunning {
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switch alloc.DesiredStatus {
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case structs.AllocDesiredStatusStop:
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onDeletedAllocation(alloc)
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case structs.AllocDesiredStatusRun:
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// is first event that marks the transition between pending and running?
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_, ok := pendingAllocations[alloc.ID]
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if ok {
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onNewAllocation(alloc)
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delete(pendingAllocations, alloc.ID)
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}
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}
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}
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if alloc.ClientStatus == structs.AllocClientStatusPending && alloc.DesiredStatus == structs.AllocDesiredStatusRun {
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// allocation is started, wait until it runs and add to our list afterwards
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pendingAllocations[alloc.ID] = true
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}
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return nil
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}
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// checkEvaluation checks whether the given evaluation failed.
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// If the evaluation failed, it returns an error with a message containing the failure information.
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func checkEvaluation(eval *nomadApi.Evaluation) (err error) {
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if len(eval.FailedTGAllocs) == 0 {
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if eval.Status != structs.EvalStatusComplete {
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err = fmt.Errorf("%w: %q", ErrorEvaluation, eval.Status)
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}
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} else {
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err = fmt.Errorf("evaluation %q finished with status %q but %w", eval.ID, eval.Status, ErrorPlacingAllocations)
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for taskGroup, metrics := range eval.FailedTGAllocs {
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err = fmt.Errorf("%w\n%s: %#v", err, taskGroup, metrics)
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}
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if eval.BlockedEval != "" {
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err = fmt.Errorf("%w\nEvaluation %q waiting for additional capacity to place remainder", err, eval.BlockedEval)
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}
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}
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return err
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}
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func (a *APIClient) MarkRunnerAsUsed(runnerID string, duration int) error {
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job, err := a.job(runnerID)
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if err != nil {
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return fmt.Errorf("couldn't retrieve job info: %w", err)
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}
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configTaskGroup := FindOrCreateConfigTaskGroup(job)
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configTaskGroup.Meta[ConfigMetaUsedKey] = ConfigMetaUsedValue
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configTaskGroup.Meta[ConfigMetaTimeoutKey] = strconv.Itoa(duration)
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_, err = a.RegisterNomadJob(job)
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if err != nil {
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return fmt.Errorf("couldn't update runner config: %w", err)
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}
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return nil
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}
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func (a *APIClient) LoadEnvironmentJobs() ([]*nomadApi.Job, error) {
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jobStubs, err := a.listJobs(TemplateJobPrefix)
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if err != nil {
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return []*nomadApi.Job{}, fmt.Errorf("couldn't load jobs: %w", err)
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}
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jobs := make([]*nomadApi.Job, 0, len(jobStubs))
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for _, jobStub := range jobStubs {
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job, err := a.apiQuerier.job(jobStub.ID)
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if err != nil {
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return []*nomadApi.Job{}, fmt.Errorf("couldn't load job info for job %v: %w", jobStub.ID, err)
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}
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jobs = append(jobs, job)
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}
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return jobs, nil
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}
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// ExecuteCommand executes the given command in the given allocation.
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// If tty is true, Nomad would normally write stdout and stderr of the command
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// both on the stdout stream. However, if the InteractiveStderr server config option is true,
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// we make sure that stdout and stderr are split correctly.
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// In order for the stderr splitting to work, the command must have the structure
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// []string{..., "sh", "-c", "my-command"}.
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func (a *APIClient) ExecuteCommand(allocationID string,
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ctx context.Context, command []string, tty bool,
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stdin io.Reader, stdout, stderr io.Writer) (int, error) {
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if tty && config.Config.Server.InteractiveStderr {
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return a.executeCommandInteractivelyWithStderr(allocationID, ctx, command, stdin, stdout, stderr)
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}
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exitCode, err := a.apiQuerier.Execute(allocationID, ctx, command, tty, stdin, stdout, stderr)
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if err != nil {
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return 1, fmt.Errorf("error executing command in API: %w", err)
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}
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return exitCode, nil
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}
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// executeCommandInteractivelyWithStderr executes the given command interactively and splits stdout
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// and stderr correctly. Normally, using Nomad to execute a command with tty=true (in order to have
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// an interactive connection and possibly a fully working shell), would result in stdout and stderr
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// to be served both over stdout. This function circumvents this by creating a fifo for the stderr
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// of the command and starting a second execution that reads the stderr from that fifo.
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func (a *APIClient) executeCommandInteractivelyWithStderr(allocationID string, ctx context.Context,
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command []string, stdin io.Reader, stdout, stderr io.Writer) (int, error) {
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// Use current nano time to make the stderr fifo kind of unique.
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currentNanoTime := time.Now().UnixNano()
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// We expect the command to be like []string{..., "sh", "-c", "my-command"}.
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oldCommand := command[len(command)-1]
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// Take the last command which is the one to be executed and wrap it to redirect stderr.
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command[len(command)-1] = wrapCommandForStderrFifo(currentNanoTime, oldCommand)
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stderrExitChan := make(chan int)
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go func() {
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// Catch stderr in separate execution.
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exit, err := a.Execute(allocationID, ctx, stderrFifoCommand(currentNanoTime), true,
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nullio.Reader{}, stderr, io.Discard)
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if err != nil {
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log.WithError(err).WithField("runner", allocationID).Warn("Stderr task finished with error")
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}
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stderrExitChan <- exit
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}()
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exit, err := a.Execute(allocationID, ctx, command, true, stdin, stdout, io.Discard)
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// Wait until the stderr catch command finished to make sure we receive all output.
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<-stderrExitChan
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return exit, err
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}
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const (
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// stderrFifoFormat represents the format we use for our stderr fifos. The %d should be unique for the execution
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// as otherwise multiple executions are not possible.
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// Example: "/tmp/stderr_1623330777825234133.fifo".
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stderrFifoFormat = "/tmp/stderr_%d.fifo"
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// stderrFifoCommandFormat, if executed, is supposed to create a fifo, read from it and remove it in the end.
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// Example: "mkfifo my.fifo && (cat my.fifo; rm my.fifo)".
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stderrFifoCommandFormat = "mkfifo %s && (cat %s; rm %s)"
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// stderrWrapperCommandFormat, if executed, is supposed to wait until a fifo exists (it sleeps 10ms to reduce load
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// cause by busy waiting on the system). Once the fifo exists, the given command is executed and its stderr
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// redirected to the fifo.
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// Example: "until [ -e my.fifo ]; do sleep 0.01; done; (echo \"my.fifo exists\") 2> my.fifo".
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stderrWrapperCommandFormat = "until [ -e %s ]; do sleep 0.01; done; (%s) 2> %s"
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)
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func stderrFifoCommand(id int64) []string {
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stderrFifoPath := stderrFifo(id)
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return []string{"sh", "-c", fmt.Sprintf(stderrFifoCommandFormat, stderrFifoPath, stderrFifoPath, stderrFifoPath)}
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}
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func wrapCommandForStderrFifo(id int64, command string) string {
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stderrFifoPath := stderrFifo(id)
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return fmt.Sprintf(stderrWrapperCommandFormat, stderrFifoPath, command, stderrFifoPath)
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}
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func stderrFifo(id int64) string {
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return fmt.Sprintf(stderrFifoFormat, id)
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}
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