hashicorp/nomad · warning

must provide log type (stdout/stderr)

Error message

must provide log type (stdout/stderr)

What it means

logTypeNotPresentErr is a sentinel error for log requests whose Type is neither "stdout" nor "stderr". The client maps this field onto a filename variant, so anything else is rejected. Returned with HTTP 400 Bad Request from the logs endpoints.

Source

Thrown at client/fs_endpoint.go:36

	"syscall"
	"time"

	metrics "github.com/hashicorp/go-metrics/compat"
	"github.com/hashicorp/go-msgpack/v2/codec"
	"github.com/hpcloud/tail/watch"

	"github.com/hashicorp/nomad/acl"
	"github.com/hashicorp/nomad/client/allocdir"
	sframer "github.com/hashicorp/nomad/client/lib/streamframer"
	cstructs "github.com/hashicorp/nomad/client/structs"
	"github.com/hashicorp/nomad/nomad/structs"
)

var (
	allocIDNotPresentErr = fmt.Errorf("must provide a valid alloc id")
	pathNotPresentErr    = fmt.Errorf("must provide a file path")
	taskNotPresentErr    = fmt.Errorf("must provide task name")
	logTypeNotPresentErr = fmt.Errorf("must provide log type (stdout/stderr)")
	invalidOrigin        = fmt.Errorf("origin must be start or end")
)

const (
	// streamFramesBuffer is the number of stream frames that will be buffered
	// before back pressure is applied on the stream framer.
	streamFramesBuffer = 32

	// streamFrameSize is the maximum number of bytes to send in a single frame
	streamFrameSize = 64 * 1024

	// streamHeartbeatRate is the rate at which a heartbeat will occur to detect
	// a closed connection without sending any additional data
	streamHeartbeatRate = 1 * time.Second

	// streamBatchWindow is the window in which file content is batched before
	// being flushed if the frame size has not been hit.
	streamBatchWindow = 200 * time.Millisecond

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Set the type parameter to exactly "stdout" or "stderr" (lowercase)
2. In code, normalize/validate the log type before the request: switch t { case "stdout", "stderr": ... default: reject }
3. If you need both streams, issue two requests rather than a combined value

Example fix

// before
req := &cstructs.FsLogsRequest{AllocID: id, Task: "web", Type: "out"}
// after
req := &cstructs.FsLogsRequest{AllocID: id, Task: "web", Type: "stdout"}

switch logType {
case "stdout", "stderr":
    // ok
default:
    return fmt.Errorf("log type must be exactly \"stdout\" or \"stderr\", got %q", logType)
}

func isValidLogType(t string) bool {
    return t == "stdout" || t == "stderr"
}

r, err := client.AllocFS().Logs(alloc, task, "", false, logType, "end", 0, ctx.Done(), nil)
if err != nil && strings.Contains(err.Error(), "must provide log type") {
    log.Printf("bad log type %q, falling back to stdout", logType)
    return client.AllocFS().Logs(alloc, task, "", false, "stdout", "end", 0, ctx.Done(), nil)
}

When it happens

Trigger: Calling logs/Logs with a req.Type value outside {"stdout", "stderr"} — empty string, "out", "1", "both", etc.

Common situations: CLI/API callers using abbreviations like 'out' or numeric fd identifiers; template variables defaulting to empty; mixing up the parameter name (passing log level or file name where type is expected).

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• must provide task name
• origin must be start or end
• missing policy name
• Unknown log level
• command is not present

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/e2df5bab80ddff9b. Report an issue: GitHub.