github.com/decred/dcrlnd@v0.7.6/labels/labels.go (about)

     1  // Package labels contains labels used to label transactions broadcast by lnd.
     2  // These labels are used across packages, so they are declared in a separate
     3  // package to avoid dependency issues.
     4  //
     5  // Labels for transactions broadcast by lnd have two set fields followed by an
     6  // optional set labelled data values, all separated by colons.
     7  //   - Label version: an integer that indicates the version lnd used
     8  //   - Label type: the type of transaction we are labelling
     9  //   - {field name}-{value}: a named field followed by its value, these items are
    10  //     optional, and there may be more than field present.
    11  //
    12  // For version 0 we have the following optional data fields defined:
    13  //   - shortchanid: the short channel ID that a transaction is associated with,
    14  //     with its value set to the uint64 short channel id.
    15  package labels
    16  
    17  import (
    18  	"fmt"
    19  
    20  	"github.com/decred/dcrlnd/lnwire"
    21  )
    22  
    23  // External labels a transaction as user initiated via the api. This
    24  // label is only used when a custom user provided label is not given.
    25  const External = "external"
    26  
    27  // TxLabelLimit is the length limit we impose on transaction labels.
    28  const TxLabelLimit = 500
    29  
    30  // ValidateAPI returns the generic api label if the label provided is empty.
    31  // This allows us to label all transactions published by the api, even if
    32  // no label is provided. If a label is provided, it is validated against
    33  // the known restrictions.
    34  func ValidateAPI(label string) (string, error) {
    35  	if len(label) > TxLabelLimit {
    36  		return "", fmt.Errorf("label length: %v exceeds "+
    37  			"limit of %v", len(label), TxLabelLimit)
    38  	}
    39  
    40  	// If no label was provided by the user, add the generic user
    41  	// send label.
    42  	if len(label) == 0 {
    43  		return External, nil
    44  	}
    45  
    46  	return label, nil
    47  }
    48  
    49  // LabelVersion versions our labels so they can be easily update to contain
    50  // new data while still easily string matched.
    51  type LabelVersion uint8
    52  
    53  // LabelVersionZero is the label version for labels that contain label type and
    54  // channel ID (where available).
    55  const LabelVersionZero LabelVersion = iota
    56  
    57  // LabelType indicates the type of label we are creating. It is a string rather
    58  // than an int for easy string matching and human-readability.
    59  type LabelType string
    60  
    61  const (
    62  	// LabelTypeChannelOpen is used to label channel opens.
    63  	LabelTypeChannelOpen LabelType = "openchannel"
    64  
    65  	// LabelTypeChannelClose is used to label channel closes.
    66  	LabelTypeChannelClose LabelType = "closechannel"
    67  
    68  	// LabelTypeJusticeTransaction is used to label justice transactions.
    69  	LabelTypeJusticeTransaction LabelType = "justicetx"
    70  
    71  	// LabelTypeSweepTransaction is used to label sweeps.
    72  	LabelTypeSweepTransaction LabelType = "sweep"
    73  )
    74  
    75  // LabelField is used to tag a value within a label.
    76  type LabelField string
    77  
    78  const (
    79  	// ShortChanID is used to tag short channel id values in our labels.
    80  	ShortChanID LabelField = "shortchanid"
    81  )
    82  
    83  // MakeLabel creates a label with the provided type and short channel id. If
    84  // our short channel ID is not known, we simply return version:label_type. If
    85  // we do have a short channel ID set, the label will also contain its value:
    86  // shortchanid-{int64 chan ID}.
    87  func MakeLabel(labelType LabelType, channelID *lnwire.ShortChannelID) string {
    88  	if channelID == nil {
    89  		return fmt.Sprintf("%v:%v", LabelVersionZero, labelType)
    90  	}
    91  
    92  	return fmt.Sprintf("%v:%v:%v-%v", LabelVersionZero, labelType,
    93  		ShortChanID, channelID.ToUint64())
    94  }