[ANCHOR-508] SEP-6: Custody integration (#1179)

### Description

This implements the custody service RPC actions. This includes payments
as well as refunds.

### Context

SEP-6 will support custodians.

### Testing

- `./gradlew test`

### Documentation

- [stellar-docs](stellar/stellar-docs#253)

### Known limitations

N/A

.github/workflows/sub_gradle_test_and_build.yml

@@ -42,7 +42,7 @@ jobs:
 
       # Prepare Stellar Validation Tests
       - name: Pull Stellar Validation Tests Docker Image
-        run: docker pull stellar/anchor-tests:v0.6.7 &
+        run: docker pull stellar/anchor-tests:v0.6.9 &
 
       # Set up JDK 11
       - name: Set up JDK 11
@@ -109,7 +109,7 @@ jobs:
 
       - name: Run Stellar validation tool
         run: |
-          docker run --network host -v ${GITHUB_WORKSPACE}/platform/src/test/resources://config stellar/anchor-tests:v0.6.7 --home-domain http://host.docker.internal:8080 --seps 1 6 10 12 24 31 38 --sep-config //config/stellar-anchor-tests-sep-config.json --verbose
+          docker run --network host -v ${GITHUB_WORKSPACE}/platform/src/test/resources://config stellar/anchor-tests:v0.6.9 --home-domain http://host.docker.internal:8080 --seps 1 6 10 12 24 31 38 --sep-config //config/stellar-anchor-tests-sep-config.json --verbose
 
       - name: Upload Artifacts
         if: always()

core/src/main/java/org/stellar/anchor/config/Sep6Config.java

@@ -11,6 +11,8 @@ public interface Sep6Config {
 
   Features getFeatures();
 
+  DepositInfoGeneratorType getDepositInfoGeneratorType();
+
   @Getter
   @Setter
   @AllArgsConstructor
@@ -22,4 +24,10 @@ class Features {
     @SerializedName("claimable_balances")
     boolean claimableBalances;
   }
+
+  enum DepositInfoGeneratorType {
+    SELF,
+    CUSTODY,
+    NONE
+  }
 }

core/src/main/java/org/stellar/anchor/custody/CustodyService.java

@@ -5,9 +5,18 @@
 import org.stellar.anchor.api.rpc.method.DoStellarRefundRequest;
 import org.stellar.anchor.sep24.Sep24Transaction;
 import org.stellar.anchor.sep31.Sep31Transaction;
+import org.stellar.anchor.sep6.Sep6Transaction;
 
 public interface CustodyService {
 
+  /**
+   * Create custody transaction for SEP6 transaction
+   *
+   * @param txn SEP6 transaction
+   * @throws AnchorException if error happens
+   */
+  void createTransaction(Sep6Transaction txn) throws AnchorException;
+
   /**
    * Create custody transaction for SEP24 transaction
    *

core/src/main/java/org/stellar/anchor/sep6/Sep6DepositInfoGenerator.java

@@ -0,0 +1,16 @@
+package org.stellar.anchor.sep6;
+
+import org.stellar.anchor.api.exception.AnchorException;
+import org.stellar.anchor.api.shared.SepDepositInfo;
+
+public interface Sep6DepositInfoGenerator {
+
+  /**
+   * Gets the deposit info based on the input parameter.
+   *
+   * @param txn the original SEP-6 transaction the deposit info will be used for.
+   * @return a SepDepositInfo instance containing the destination address, memo and memoType.
+   * @throws AnchorException if the deposit info cannot be generated
+   */
+  SepDepositInfo generate(Sep6Transaction txn) throws AnchorException;
+}

core/src/main/java/org/stellar/anchor/sep6/Sep6Service.java

@@ -1,7 +1,6 @@
 package org.stellar.anchor.sep6;
 
 import static org.stellar.anchor.util.MemoHelper.*;
-import static org.stellar.sdk.xdr.MemoType.MEMO_HASH;
 
 import com.google.common.collect.ImmutableMap;
 import java.time.Instant;
@@ -190,7 +189,6 @@ public StartDepositResponse depositExchange(Sep10Jwt token, StartDepositExchange
             .amountFee(amounts.getAmountFee())
             .amountFeeAsset(amounts.getAmountFeeAsset())
             .amountExpected(request.getAmount())
-            .amountExpected(request.getAmount())
             .startedAt(Instant.now())
             .sep10Account(token.getAccount())
             .sep10AccountMemo(token.getAccountMemo())
@@ -270,10 +268,7 @@ public StartWithdrawResponse withdraw(Sep10Jwt token, StartWithdrawRequest reque
             .startedAt(Instant.now())
             .sep10Account(token.getAccount())
             .sep10AccountMemo(token.getAccountMemo())
-            .memo(generateMemo(id))
-            .memoType(memoTypeAsString(MEMO_HASH))
             .fromAccount(sourceAccount)
-            .withdrawAnchorAccount(asset.getDistributionAccount())
             .refundMemo(request.getRefundMemo())
             .refundMemoType(request.getRefundMemoType());
 
@@ -288,12 +283,7 @@ public StartWithdrawResponse withdraw(Sep10Jwt token, StartWithdrawRequest reque
             .transaction(TransactionHelper.toGetTransactionResponse(txn, assetService))
             .build());
 
-    return StartWithdrawResponse.builder()
-        .accountId(asset.getDistributionAccount())
-        .id(txn.getId())
-        .memo(txn.getMemo())
-        .memoType(memoTypeAsString(MEMO_HASH))
-        .build();
+    return StartWithdrawResponse.builder().id(txn.getId()).build();
   }
 
   public StartWithdrawResponse withdrawExchange(
@@ -364,10 +354,7 @@ public StartWithdrawResponse withdrawExchange(
             .startedAt(Instant.now())
             .sep10Account(token.getAccount())
             .sep10AccountMemo(token.getAccountMemo())
-            .memo(generateMemo(id))
-            .memoType(memoTypeAsString(MEMO_HASH))
             .fromAccount(sourceAccount)
-            .withdrawAnchorAccount(sellAsset.getDistributionAccount())
             .refundMemo(request.getRefundMemo())
             .refundMemoType(request.getRefundMemoType())
             .quoteId(request.getQuoteId());
@@ -383,12 +370,7 @@ public StartWithdrawResponse withdrawExchange(
             .transaction(TransactionHelper.toGetTransactionResponse(txn, assetService))
             .build());
 
-    return StartWithdrawResponse.builder()
-        .accountId(sellAsset.getDistributionAccount())
-        .id(txn.getId())
-        .memo(txn.getMemo())
-        .memoType(memoTypeAsString(MEMO_HASH))
-        .build();
+    return StartWithdrawResponse.builder().id(txn.getId()).build();
   }
 
   public GetTransactionsResponse findTransactions(Sep10Jwt token, GetTransactionsRequest request)

core/src/main/java/org/stellar/anchor/util/MemoHelper.java

@@ -6,7 +6,6 @@
 import java.util.Base64;
 import org.apache.commons.codec.DecoderException;
 import org.apache.commons.codec.binary.Hex;
-import org.apache.commons.lang3.StringUtils;
 import org.stellar.anchor.api.exception.SepException;
 import org.stellar.anchor.api.exception.SepValidationException;
 import org.stellar.sdk.*;
@@ -126,10 +125,4 @@ public static String memoAsString(Memo memo) throws SepException {
         throw new SepException("Unsupported value: " + memoTypeStr);
     }
   }
-
-  public static String generateMemo(String transactionId) {
-    String memo = StringUtils.truncate(transactionId, 32);
-    memo = StringUtils.leftPad(memo, 32, "0");
-    return new String(Base64.getEncoder().encode(memo.getBytes()));
-  }
 }

core/src/main/java/org/stellar/anchor/util/TransactionHelper.java

@@ -1,9 +1,8 @@
 package org.stellar.anchor.util;
 
-import static org.stellar.anchor.api.platform.PlatformTransactionData.Kind.DEPOSIT;
-import static org.stellar.anchor.api.platform.PlatformTransactionData.Kind.RECEIVE;
-import static org.stellar.anchor.api.platform.PlatformTransactionData.Kind.WITHDRAWAL;
+import static org.stellar.anchor.api.platform.PlatformTransactionData.Kind.*;
 
+import com.google.common.collect.ImmutableSet;
 import java.util.Optional;
 import javax.annotation.Nullable;
 import org.stellar.anchor.api.custody.CreateCustodyTransactionRequest;
@@ -22,6 +21,33 @@
 
 public class TransactionHelper {
 
+  public static CreateCustodyTransactionRequest toCustodyTransaction(Sep6Transaction txn) {
+    PlatformTransactionData.Kind kind = PlatformTransactionData.Kind.from(txn.getKind());
+    return CreateCustodyTransactionRequest.builder()
+        .id(txn.getId())
+        .memo(txn.getMemo())
+        .memoType(txn.getMemoType())
+        .protocol("6")
+        .fromAccount(
+            ImmutableSet.of(WITHDRAWAL, WITHDRAWAL_EXCHANGE).contains(kind)
+                ? txn.getFromAccount()
+                : null)
+        .toAccount(
+            ImmutableSet.of(DEPOSIT, DEPOSIT_EXCHANGE).contains(kind)
+                ? txn.getToAccount()
+                : txn.getWithdrawAnchorAccount())
+        .amount(
+            ImmutableSet.of(DEPOSIT, DEPOSIT_EXCHANGE).contains(kind)
+                ? txn.getAmountOut()
+                : Optional.ofNullable(txn.getAmountExpected()).orElse(txn.getAmountIn()))
+        .asset(
+            ImmutableSet.of(DEPOSIT, DEPOSIT_EXCHANGE).contains(kind)
+                ? txn.getAmountOutAsset()
+                : txn.getAmountInAsset())
+        .kind(txn.getKind())
+        .build();
+  }
+
   public static CreateCustodyTransactionRequest toCustodyTransaction(Sep24Transaction txn) {
     return CreateCustodyTransactionRequest.builder()
         .id(txn.getId())

core/src/test/kotlin/org/stellar/anchor/sep6/Sep6ServiceTest.kt

@@ -657,8 +657,6 @@ class Sep6ServiceTest {
       JSONCompareMode.LENIENT
     )
     assert(slotTxn.captured.id.isNotEmpty())
-    assert(slotTxn.captured.memo.isNotEmpty())
-    assertEquals(slotTxn.captured.memoType, "hash")
     assertNotNull(slotTxn.captured.startedAt)
 
     JSONAssert.assertEquals(
@@ -668,8 +666,6 @@ class Sep6ServiceTest {
     )
     assert(slotEvent.captured.id.isNotEmpty())
     assert(slotEvent.captured.transaction.id.isNotEmpty())
-    assert(slotEvent.captured.transaction.memo.isNotEmpty())
-    assertEquals(slotEvent.captured.transaction.memoType, "hash")
     assertNotNull(slotEvent.captured.transaction.startedAt)
 
     // Verify response
@@ -738,8 +734,6 @@ class Sep6ServiceTest {
       JSONCompareMode.LENIENT
     )
     assert(slotTxn.captured.id.isNotEmpty())
-    assert(slotTxn.captured.memo.isNotEmpty())
-    assertEquals(slotTxn.captured.memoType, "hash")
     assertNotNull(slotTxn.captured.startedAt)
 
     JSONAssert.assertEquals(
@@ -749,8 +743,6 @@ class Sep6ServiceTest {
     )
     assert(slotEvent.captured.id.isNotEmpty())
     assert(slotEvent.captured.transaction.id.isNotEmpty())
-    assert(slotEvent.captured.transaction.memo.isNotEmpty())
-    assertEquals(slotEvent.captured.transaction.memoType, "hash")
     assertNotNull(slotEvent.captured.transaction.startedAt)
 
     // Verify response
@@ -945,8 +937,6 @@ class Sep6ServiceTest {
       JSONCompareMode.LENIENT
     )
     assert(slotTxn.captured.id.isNotEmpty())
-    assert(slotTxn.captured.memo.isNotEmpty())
-    assertEquals(slotTxn.captured.memoType, "hash")
     assertNotNull(slotTxn.captured.startedAt)
 
     JSONAssert.assertEquals(
@@ -956,8 +946,6 @@ class Sep6ServiceTest {
     )
     assert(slotEvent.captured.id.isNotEmpty())
     assert(slotEvent.captured.transaction.id.isNotEmpty())
-    assert(slotEvent.captured.transaction.memo.isNotEmpty())
-    assertEquals(slotEvent.captured.transaction.memoType, "hash")
     assertNotNull(slotEvent.captured.transaction.startedAt)
 
     // Verify response
@@ -1018,8 +1006,6 @@ class Sep6ServiceTest {
       JSONCompareMode.LENIENT
     )
     assert(slotTxn.captured.id.isNotEmpty())
-    assert(slotTxn.captured.memo.isNotEmpty())
-    assertEquals(slotTxn.captured.memoType, "hash")
     assertNotNull(slotTxn.captured.startedAt)
 
     JSONAssert.assertEquals(
@@ -1029,8 +1015,6 @@ class Sep6ServiceTest {
     )
     assert(slotEvent.captured.id.isNotEmpty())
     assert(slotEvent.captured.transaction.id.isNotEmpty())
-    assert(slotEvent.captured.transaction.memo.isNotEmpty())
-    assertEquals(slotEvent.captured.transaction.memoType, "hash")
     assertNotNull(slotEvent.captured.transaction.startedAt)
 
     // Verify response

core/src/test/kotlin/org/stellar/anchor/sep6/Sep6ServiceTestData.kt

@@ -388,10 +388,8 @@ class Sep6ServiceTestData {
     val withdrawResJson =
       """
       {
-          "account_id": "GA7FYRB5VREZKOBIIKHG5AVTPFGWUBPOBF7LTYG4GTMFVIOOD2DWAL7I",
-          "memo_type": "hash"
       }
-    """
+      """
         .trimIndent()
 
     val withdrawTxnJson =
@@ -411,9 +409,7 @@ class Sep6ServiceTestData {
           "amountExpected": "100",
           "sep10Account": "GBLGJA4TUN5XOGTV6WO2BWYUI2OZR5GYQ5PDPCRMQ5XEPJOYWB2X4CJO",
           "sep10AccountMemo": "123",
-          "withdrawAnchorAccount": "GA7FYRB5VREZKOBIIKHG5AVTPFGWUBPOBF7LTYG4GTMFVIOOD2DWAL7I",
           "fromAccount": "GBLGJA4TUN5XOGTV6WO2BWYUI2OZR5GYQ5PDPCRMQ5XEPJOYWB2X4CJO",
-          "memoType": "hash",
           "refundMemo": "some text",
           "refundMemoType": "text"
         }
@@ -446,7 +442,6 @@ class Sep6ServiceTestData {
               "asset": "stellar:USDC:GDQOE23CFSUMSVQK4Y5JHPPYK73VYCNHZHA7ENKCV37P6SUEO6XQBKPP"
             },
             "source_account": "GBLGJA4TUN5XOGTV6WO2BWYUI2OZR5GYQ5PDPCRMQ5XEPJOYWB2X4CJO",
-            "memo_type": "hash",
             "refund_memo": "some text",
             "refund_memo_type": "text",
             "customers": {
@@ -477,9 +472,7 @@ class Sep6ServiceTestData {
           "amountFeeAsset": "stellar:USDC:GDQOE23CFSUMSVQK4Y5JHPPYK73VYCNHZHA7ENKCV37P6SUEO6XQBKPP",
           "sep10Account": "GBLGJA4TUN5XOGTV6WO2BWYUI2OZR5GYQ5PDPCRMQ5XEPJOYWB2X4CJO",
           "sep10AccountMemo": "123",
-          "withdrawAnchorAccount": "GA7FYRB5VREZKOBIIKHG5AVTPFGWUBPOBF7LTYG4GTMFVIOOD2DWAL7I",
           "fromAccount": "GBLGJA4TUN5XOGTV6WO2BWYUI2OZR5GYQ5PDPCRMQ5XEPJOYWB2X4CJO",
-          "memoType": "hash",
           "refundMemo": "some text",
           "refundMemoType": "text"
         }
@@ -503,7 +496,6 @@ class Sep6ServiceTestData {
               "asset": "stellar:USDC:GDQOE23CFSUMSVQK4Y5JHPPYK73VYCNHZHA7ENKCV37P6SUEO6XQBKPP"
             },
             "source_account": "GBLGJA4TUN5XOGTV6WO2BWYUI2OZR5GYQ5PDPCRMQ5XEPJOYWB2X4CJO",
-            "memo_type": "hash",
             "refund_memo": "some text",
             "refund_memo_type": "text",
             "customers": {
@@ -538,9 +530,7 @@ class Sep6ServiceTestData {
           "amountExpected": "100",
           "sep10Account": "GBLGJA4TUN5XOGTV6WO2BWYUI2OZR5GYQ5PDPCRMQ5XEPJOYWB2X4CJO",
           "sep10AccountMemo": "123",
-          "withdrawAnchorAccount": "GA7FYRB5VREZKOBIIKHG5AVTPFGWUBPOBF7LTYG4GTMFVIOOD2DWAL7I",
           "fromAccount": "GBLGJA4TUN5XOGTV6WO2BWYUI2OZR5GYQ5PDPCRMQ5XEPJOYWB2X4CJO",
-          "memoType": "hash",
           "quoteId": "test-quote-id",
           "refundMemo": "some text",
           "refundMemoType": "text"
@@ -569,7 +559,6 @@ class Sep6ServiceTestData {
             "amount_fee": { "amount": "2", "asset": "iso4217:USD" },
             "quote_id": "test-quote-id",
             "source_account": "GBLGJA4TUN5XOGTV6WO2BWYUI2OZR5GYQ5PDPCRMQ5XEPJOYWB2X4CJO",
-            "memo_type": "hash",
             "refund_memo": "some text",
             "refund_memo_type": "text",
             "customers": {
@@ -604,9 +593,7 @@ class Sep6ServiceTestData {
           "amountExpected": "100",
           "sep10Account": "GBLGJA4TUN5XOGTV6WO2BWYUI2OZR5GYQ5PDPCRMQ5XEPJOYWB2X4CJO",
           "sep10AccountMemo": "123",
-          "withdrawAnchorAccount": "GA7FYRB5VREZKOBIIKHG5AVTPFGWUBPOBF7LTYG4GTMFVIOOD2DWAL7I",
           "fromAccount": "GBLGJA4TUN5XOGTV6WO2BWYUI2OZR5GYQ5PDPCRMQ5XEPJOYWB2X4CJO",
-          "memoType": "hash",
           "refundMemo": "some text",
           "refundMemoType": "text"
         }
@@ -637,7 +624,6 @@ class Sep6ServiceTestData {
               "asset": "stellar:USDC:GDQOE23CFSUMSVQK4Y5JHPPYK73VYCNHZHA7ENKCV37P6SUEO6XQBKPP"
             },
             "source_account": "GBLGJA4TUN5XOGTV6WO2BWYUI2OZR5GYQ5PDPCRMQ5XEPJOYWB2X4CJO",
-            "memo_type": "hash",
             "refund_memo": "some text",
             "refund_memo_type": "text",
             "customers": {

integration-tests/src/test/kotlin/org/stellar/anchor/platform/AnchorPlatformCustodyEnd2EndTest.kt

@@ -28,4 +28,12 @@ class AnchorPlatformCustodyEnd2EndTest :
   fun runSep24Test() {
     singleton.sep24CustodyE2eTests.testAll()
   }
+
+  @Test
+  @Order(11)
+  fun runSep6Test() {
+    // The SEP-6 reference server implementation only implements RPC, so technically this test
+    // should be in the RPC test suite.
+    singleton.sep6E2eTests.testAll()
+  }
 }

integration-tests/src/test/kotlin/org/stellar/anchor/platform/AnchorPlatformEnd2EndTest.kt

@@ -31,6 +31,8 @@ class AnchorPlatformEnd2EndTest : AbstractIntegrationTest(TestConfig(testProfile
   @Test
   @Order(2)
   fun runSep6Test() {
+    // The SEP-6 reference server implementation only implements RPC, so technically this test
+    // should be in the RPC test suite.
     singleton.sep6E2eTests.testAll()
   }
 }