ipfs/kubo · error

CheckCIDSize: getting dag: %w

Error message

CheckCIDSize: getting dag: %w

What it means

CheckCIDSize fetches the DAG node for a CID via dagAPI.Get before enforcing the 2MiB block-size limit. If fetching the node fails (block not found, datastore error, context cancel), the cause is wrapped with this prefix. It is a wrapping error: the real reason is the wrapped err.

Source

Thrown at core/commands/cmdutils/utils.go:32

const (
	AllowBigBlockOptionName = "allow-big-block"
	// SoftBlockLimit is the maximum block size for bitswap transfer.
	// If this value changes, update the "2MiB" strings in error messages below.
	SoftBlockLimit  = 2 * 1024 * 1024 // https://specs.ipfs.tech/bitswap-protocol/#block-sizes
	MaxPinNameBytes = 255             // Maximum number of bytes allowed for a pin name
)

var AllowBigBlockOption cmds.Option

func init() {
	AllowBigBlockOption = cmds.BoolOption(AllowBigBlockOptionName, "Disable block size check and allow creation of blocks bigger than 2MiB. WARNING: such blocks won't be transferable over the standard bitswap.").WithDefault(false)
}

func CheckCIDSize(req *cmds.Request, c cid.Cid, dagAPI coreiface.APIDagService) error {
	n, err := dagAPI.Get(req.Context, c)
	if err != nil {
		return fmt.Errorf("CheckCIDSize: getting dag: %w", err)
	}

	nodeSize, err := n.Size()
	if err != nil {
		return fmt.Errorf("CheckCIDSize: getting node size: %w", err)
	}

	return CheckBlockSize(req, nodeSize)
}

func CheckBlockSize(req *cmds.Request, size uint64) error {
	allowAnyBlockSize, _ := req.Options[AllowBigBlockOptionName].(bool)
	if allowAnyBlockSize {
		return nil
	}

	// Block size is limited to SoftBlockLimit (2MiB) as defined in the bitswap spec.
	// https://specs.ipfs.tech/bitswap-protocol/#block-sizes

View on GitHub (pinned to 329838acdf)

Solutions

1. Inspect the wrapped error for the real cause (not found, timeout, context cancelled)
2. Ensure the block exists locally or the node can fetch it (routing/peers online)
3. Verify the CID is valid for the configured codec/resolver
4. Retry if the failure was a transient network/context issue

// ensure block is present before size check
_, err := dagAPI.Get(ctx, c)
if err != nil {
    return fmt.Errorf("block unavailable, aborting size check: %w", err)
}

if err := cmdutils.CheckCIDSize(req, c, dagAPI); err != nil {
    if errors.Is(err, context.Canceled) || isNotFound(err) {
        return err // non-retryable
    }
    // transient: retry with backoff
}

When it happens

Trigger: Calling dag put/export paths that call CheckCIDSize with a CID that is not in the local store, a malformed/unresolvable CID, cancelled request context, or a failing blockservice/datastore.

Common situations: `ipfs dag put` with --allow-of-big-block logic on a CID that hasn't been fetched; operations on offloaded blocks when the daemon is offline; context cancelled mid-request.

Related errors

• CheckCIDSize: getting node size: %w
• dagStore: key was not a cid: %w
• dagStore: key was not a cid: had %d bytes leftover
• checking if new root exists: %w
• new root %s does not exist locally; fetch it first with 'ipf

AI-assisted analysis of ipfs/kubo@329838acdf (2026-09-03). Data as JSON: /api/errors/e12ced0a12710ae0. Report an issue: GitHub.