xdr2go

xdr2go is a little CLI tool to transform base64 XDR objects into a pretty Go code. This helps in writing mocks and testing. It's using fmt.GoStringer interface to print pretty Go code compared to a standard library implementation.

Why

Very often when writing tests we mock objects to make tests independent of other components. There are many ways we can create example XDR objects but they have disadvantages:

• For transactions we can use txnbuild package. The problem is that it allows building transactions only. Also, sometimes there's an existing transaction in the network we want to use in tests so building it using txnbuild requires extra time.
• fmt.Printf("%#v", value) prints a Go-syntax representation of the value. However, there are many problems with the way the values are printed using a standard GoStringer:
  • If the value is a struct with pointers it prints an hexadecimal memory address instead of it's value, ex:

    &xdr.TransactionEnvelope{Type: 2, V0: (*xdr.TransactionV0Envelope)(nil), V1: (*xdr.TransactionV1Envelope)(0xc0000aa2d0), FeeBump: (*xdr.FeeBumpTransactionEnvelope)(nil)
    

  • It prints redundant nil values that could be skipped.
  • Binary values like ed25519 keys and unions (ex. xdr.Asset) are rendered in a way that's hard to read.
  • Union discriminants are printed as decimal, instead of using a type variable.
  • uint32 values are printed in hex.
• I also checked https://godoc.org/github.com/kr/pretty. While it works fine, it also doesn't skip nil values and prints binary values and unions as standard Go printer.

Standard print:

xdr.TransactionEnvelope{Type: 2, V0: (*xdr.TransactionV0Envelope)(nil), V1: (*xdr.TransactionV1Envelope)(0xc0000aa2d0), FeeBump: (*xdr.FeeBumpTransactionEnvelope)(nil)

With GoStringer implementations:

xdr.TransactionEnvelope{Type: xdr.EnvelopeTypeEnvelopeTypeTx, V1: &xdr.TransactionV1Envelope{Tx: xdr.Transaction{SourceAccount: xdr.MustAddress("GAZ3T7HRWDBJ6SNQ7IWVUS65FP6QMCWHCALFYWX552KFV2O2RLOSRLKI"), Fee: 120, SeqNum: 122783846453215886, TimeBounds: &xdr.TimeBounds{MinTime: xdr.TimePoint(0), MaxTime: xdr.TimePoint(1594645065)}, Memo: xdr.Memo{Type: xdr.MemoTypeMemoNone}, Operations: []xdr.Operation{xdr.OperationBody{SourceAccount: &xdr.MustAddress("GBHC6AMZ3FWLYYHXITCIEZI6VXAU4IEMRCHLICXZXHOVSBFSWCRJ7JS7"), Body: &xdr.OperationBody{Type: xdr.OperationTypeManageSellOffer, ManageSellOfferOp: &xdr.ManageSellOfferOp{Selling: xdr.MustNewCreditAsset("LFEC", "GAG6FS3CR64QJHLHJU7HNXUB4KBLXVDFQBDXM5LG22WOM7CA2ITJAVD2"), Buying: xdr.MustNewNativeAsset(), Amount: 6, Price: xdr.Price{N: 9899999, D: 100000000}, OfferId: 0}}}}, Ext: xdr.TransactionExt{V: 0}}, Signatures: []xdr.DecoratedSignature{xdr.DecoratedSignature{Hint: xdr.SignatureHint{0xda, 0x8a, 0xdd, 0x28}, Signature: xdr.Signature{0x55, 0xb, 0xd0, 0x7d, 0xf3, 0x7, 0x71, 0x56, 0x99, 0x3c, 0x34, 0xfc, 0x47, 0xa0, 0xce, 0x2b, 0x39, 0xa, 0xc4, 0x8c, 0xb7, 0x80, 0x9f, 0x4c, 0xc8, 0x22, 0xae, 0xcc, 0xe9, 0x8b, 0x29, 0xb9, 0x80, 0x94, 0xab, 0x15, 0xbd, 0x6b, 0xc6, 0x3e, 0x2d, 0x12, 0x7a, 0x49, 0xa8, 0x83, 0x75, 0xdd, 0x21, 0x0, 0x14, 0x47, 0xdc, 0xf9, 0x4, 0xe7, 0xdb, 0x16, 0x5a, 0x6e, 0xb0, 0xd6, 0xc0, 0xd}}, xdr.DecoratedSignature{Hint: xdr.SignatureHint{0xb2, 0xb0, 0xa2, 0x9f}, Signature: xdr.Signature{0x6c, 0xb8, 0xe4, 0xd6, 0x39, 0xe2, 0x54, 0x3a, 0x51, 0xf1, 0xc1, 0x20, 0xb9, 0x5f, 0x7d, 0x8, 0xae, 0x31, 0x2c, 0xec, 0x19, 0xce, 0xb0, 0x3f, 0xb6, 0xe6, 0xfa, 0x25, 0xeb, 0x58, 0xf0, 0x33, 0xd1, 0x9f, 0x9a, 0xf5, 0xc2, 0x33, 0x7b, 0xa6, 0x45, 0x92, 0x18, 0xc0, 0x4d, 0xbf, 0x9d, 0xdf, 0xa0, 0xa5, 0x43, 0x73, 0x2a, 0x7c, 0x7d, 0xad, 0x67, 0x54, 0xad, 0xa6, 0xae, 0x30, 0xd1, 0xf}}}}}