Add metadata (#33)

- Add support for arbitrary JSON metadata on transactions & accounts

Co-authored-by: Azorlogh <[email protected]>

api/http.go

@@ -104,9 +104,15 @@ func NewHttpAPI(lc fx.Lifecycle, resolver *ledger.Resolver) *HttpAPI {
 
 		err := l.(*ledger.Ledger).Commit([]core.Transaction{t})
 
-		c.JSON(200, gin.H{
+		res := gin.H{
 			"ok": err == nil,
-		})
+		}
+
+		if err != nil {
+			res["err"] = err.Error()
+		}
+
+		c.JSON(200, res)
 	})
 
 	r.POST("/:ledger/script", func(c *gin.Context) {
@@ -175,6 +181,52 @@ func NewHttpAPI(lc fx.Lifecycle, resolver *ledger.Resolver) *HttpAPI {
 		c.JSON(200, res)
 	})
 
+	r.POST("/:ledger/transactions/:id/metadata", func(c *gin.Context) {
+		l, _ := c.Get("ledger")
+
+		var m core.Metadata
+		c.ShouldBind(&m)
+
+		err := l.(*ledger.Ledger).SaveMeta(
+			"transaction",
+			c.Param("id"),
+			m,
+		)
+
+		res := gin.H{
+			"ok": err == nil,
+		}
+
+		if err != nil {
+			res["err"] = err.Error()
+		}
+
+		c.JSON(200, res)
+	})
+
+	r.POST("/:ledger/accounts/:id/metadata", func(c *gin.Context) {
+		l, _ := c.Get("ledger")
+
+		var m core.Metadata
+		c.ShouldBind(&m)
+
+		err := l.(*ledger.Ledger).SaveMeta(
+			"account",
+			c.Param("id"),
+			m,
+		)
+
+		res := gin.H{
+			"ok": err == nil,
+		}
+
+		if err != nil {
+			res["err"] = err.Error()
+		}
+
+		c.JSON(200, res)
+	})
+
 	h := &HttpAPI{
 		engine: r,
 		addr:   viper.GetString("server.http.bind_address"),

core/account.go

@@ -10,4 +10,5 @@ type Account struct {
 	Type     string                      `json:"type,omitempty"`
 	Balances map[string]int64            `json:"balances,omitempty"`
 	Volumes  map[string]map[string]int64 `json:"volumes,omitempty"`
+	Metadata Metadata                    `json:"metadata"`
 }

core/metadata.go

@@ -1,3 +1,5 @@
 package core
 
-type Metadata map[string]interface{}
+import "encoding/json"
+
+type Metadata map[string]json.RawMessage

go.mod

@@ -5,10 +5,11 @@ go 1.16
 require (
 	github.com/gin-contrib/cors v1.3.1
 	github.com/gin-gonic/gin v1.7.1
+	github.com/google/go-cmp v0.5.6 // indirect
 	github.com/huandu/go-sqlbuilder v1.12.1
 	github.com/jackc/pgx/v4 v4.11.0
 	github.com/mattn/go-sqlite3 v1.14.7
-	github.com/numary/machine v0.0.0-20210726090747-5853ebec28f0
+	github.com/numary/machine v0.0.0-20210803145033-12db2afffb8d
 	github.com/pkg/errors v0.8.1
 	github.com/spf13/cobra v1.1.3
 	github.com/spf13/viper v1.8.1

go.sum

@@ -415,8 +415,12 @@ github.com/nats-io/nkeys v0.1.3/go.mod h1:xpnFELMwJABBLVhffcfd1MZx6VsNRFpEugbxzi
 github.com/nats-io/nuid v1.0.1/go.mod h1:19wcPz3Ph3q0Jbyiqsd0kePYG7A95tJPxeL+1OSON2c=
 github.com/numary/ledger v0.0.0-20210702172952-a5bd30e551d0/go.mod h1:u2K28z9TDYd6id1qeD2uv7JDlajuRZ0fvOnCeDZmDxk=
 github.com/numary/machine v0.0.0-20210702091459-23a82555adbf/go.mod h1:WAFvefAGYNjdDmPtDoZ305F58QDtUJyB0QWN3vzSZao=
-github.com/numary/machine v0.0.0-20210726090747-5853ebec28f0 h1:TM2r/u2KwZBipmd6s5q/mzlzWfNCFwEadH9xyYbvZAw=
-github.com/numary/machine v0.0.0-20210726090747-5853ebec28f0/go.mod h1:azMZte4ywWM0ISNMgMII4IS9XJ0N3ZAB7TfQ2Ay3dL0=
+github.com/numary/machine v0.0.0-20210729165957-aa92270b0f57 h1:hMGEr+3Ld+hhJCdIG9OUCh+igSIMvKLqx0r2UEf964Q=
+github.com/numary/machine v0.0.0-20210729165957-aa92270b0f57/go.mod h1:KulcZIlMidEjXmuFSGNckmk0pKr4HFKFYy3bB+ksWSQ=
+github.com/numary/machine v0.0.0-20210730150440-46c0133da7be h1:Zn0JK8STaFzc2O1Vw7IcitVQLE+buvybu99J8zaIe9k=
+github.com/numary/machine v0.0.0-20210730150440-46c0133da7be/go.mod h1:KulcZIlMidEjXmuFSGNckmk0pKr4HFKFYy3bB+ksWSQ=
+github.com/numary/machine v0.0.0-20210803145033-12db2afffb8d h1:Z6nbKlnn/kCZjMXEh6Upscg+7V0+ZhxJFJZLCR1ctAY=
+github.com/numary/machine v0.0.0-20210803145033-12db2afffb8d/go.mod h1:KulcZIlMidEjXmuFSGNckmk0pKr4HFKFYy3bB+ksWSQ=
 github.com/oklog/oklog v0.3.2/go.mod h1:FCV+B7mhrz4o+ueLpx+KqkyXRGMWOYEvfiXtdGtbWGs=
 github.com/oklog/run v1.0.0/go.mod h1:dlhp/R75TPv97u0XWUtDeV/lRKWPKSdTuV0TZvrmrQA=
 github.com/oklog/ulid v1.3.1/go.mod h1:CirwcVhetQ6Lv90oh/F+FBtV6XMibvdAFo93nm5qn4U=

ledger/executor.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 
 	"github.com/numary/ledger/core"
+	machine "github.com/numary/machine/core"
 	"github.com/numary/machine/script/compiler"
 	"github.com/numary/machine/vm"
 )
@@ -18,40 +19,61 @@ func (l *Ledger) Execute(script core.Script) error {
 	if err != nil {
 		return fmt.Errorf("compile error: %v", err)
 	}
+
 	m := vm.NewMachine(p)
 
 	err = m.SetVarsFromJSON(script.Vars)
 	if err != nil {
-		return fmt.Errorf("error while setting variables: %v", err)
+		return fmt.Errorf("could not set variables: %v", err)
 	}
 
-	needed_balances, err := m.GetNeededBalances()
-	if err != nil {
-		return err
+	{
+		ch, err := m.ResolveResources()
+		if err != nil {
+			return fmt.Errorf("could not resolve program resources: %v", err)
+		}
+		for req := range ch {
+			if req.Error != nil {
+				return fmt.Errorf("could not resolve program resources: %v", req.Error)
+			}
+			account, err := l.GetAccount(req.Account)
+			if err != nil {
+				return fmt.Errorf("could not get account %q: %v", req.Account, err)
+			}
+			meta := account.Metadata
+			entry, ok := meta[req.Key]
+			if !ok {
+				return fmt.Errorf("missing key %v in metadata for account %v", req.Key, req.Account)
+			}
+			value, err := machine.NewValueFromTypedJSON(entry)
+			if err != nil {
+				return fmt.Errorf("invalid format for metadata at key %v for account %v: %v", req.Key, req.Account, err)
+			}
+			req.Response <- *value
+		}
 	}
 
-	balances := map[string]map[string]uint64{}
-
-	for account_address, needed_assets := range needed_balances {
-		account, err := l.GetAccount(account_address)
+	{
+		ch, err := m.ResolveBalances()
 		if err != nil {
-			return fmt.Errorf("invalid account address: %v\n", err)
+			return fmt.Errorf("could not resolve balances: %v", err)
 		}
-		balances[account_address] = map[string]uint64{}
-		for asset := range needed_assets {
-			amt := account.Balances[asset]
+		for req := range ch {
+			if req.Error != nil {
+				return fmt.Errorf("could not resolve balances: %v", err)
+			}
+			account, err := l.GetAccount(req.Account)
+			if err != nil {
+				return fmt.Errorf("could not get account %q: %v", req.Account, err)
+			}
+			amt := account.Balances[req.Asset]
 			if amt < 0 {
 				amt = 0
 			}
-			balances[account_address][asset] = uint64(amt)
+			req.Response <- uint64(amt)
 		}
 	}
 
-	err = m.SetBalances(balances)
-	if err != nil {
-		return err
-	}
-
 	c, err := m.Execute()
 	if err != nil {
 		return fmt.Errorf("script failed: %v", err)

ledger/executor_test.go

@@ -9,6 +9,23 @@ import (
 	"github.com/numary/ledger/core"
 )
 
+func assertBalance(t *testing.T, l *Ledger, account string, asset string, amount int64) {
+	user, err := l.GetAccount(account)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	if b := user.Balances[asset]; b != amount {
+		t.Fatalf(
+			"wrong %v balance for account %v, expected: %d got: %d",
+			asset,
+			account,
+			amount,
+			b,
+		)
+	}
+}
+
 func TestTransactionInvalidScript(t *testing.T) {
 	with(func(l *Ledger) {
 		script := core.Script{
@@ -60,20 +77,7 @@ func TestSend(t *testing.T) {
 			return
 		}
 
-		user, err := l.GetAccount("user:001")
-
-		if err != nil {
-			t.Error(err)
-			return
-		}
-
-		if b := user.Balances["USD/2"]; b != 99 {
-			t.Error(fmt.Sprintf(
-				"wrong USD/2 balance for account user:001, expected: %d got: %d",
-				99,
-				b,
-			))
-		}
+		assertBalance(t, l, "user:001", "USD/2", 99)
 	})
 }
 
@@ -190,3 +194,79 @@ func TestNotEnoughFunds(t *testing.T) {
 		}
 	})
 }
+
+func TestMetadata(t *testing.T) {
+	with(func(l *Ledger) {
+		defer l.Close()
+
+		tx := core.Transaction{
+			Postings: []core.Posting{
+				{
+					Source:      "world",
+					Destination: "sales:042",
+					Amount:      100,
+					Asset:       "COIN",
+				},
+			},
+		}
+
+		err := l.Commit([]core.Transaction{tx})
+
+		l.SaveMeta("account", "sales:042", core.Metadata{
+			"seller": json.RawMessage(`{
+				"type":  "account",
+				"value": "users:053"
+			}`),
+		})
+
+		l.SaveMeta("account", "users:053", core.Metadata{
+			"commission": json.RawMessage(`{
+				"type":  "portion",
+				"value": "15.5%"
+			}`),
+		})
+
+		if err != nil {
+			t.Error(err)
+			return
+		}
+
+		plain := `
+			vars {
+				account $sale
+				account $seller = meta($sale, "seller")
+				portion $commission = meta($seller, "commission")
+			}
+
+			send [COIN *] (
+				source = $sale
+				destination = {
+					remaining to $seller
+					$commission to @platform
+				}
+			)
+		`
+		if err != nil {
+			t.Fatalf("did not expect error: %v", err)
+		}
+
+		script := core.Script{
+			Plain: plain,
+			Vars: map[string]json.RawMessage{
+				"sale": json.RawMessage(`"sales:042"`),
+			},
+		}
+
+		err = l.Execute(script)
+
+		if err != nil {
+			t.Fatalf("execution error: %v", err)
+		}
+
+		assertBalance(t, l, "sales:042", "COIN", 0)
+
+		assertBalance(t, l, "users:053", "COIN", 85)
+
+		assertBalance(t, l, "platform", "COIN", 15)
+	})
+}

ledger/ledger.go

@@ -214,5 +214,15 @@ func (l *Ledger) GetAccount(address string) (core.Account, error) {
 
 	account.Volumes = volumes
 
+	meta, err := l.store.GetMeta("account", address)
+	if err != nil {
+		return account, err
+	}
+	account.Metadata = meta
+
 	return account, nil
 }
+
+func (l *Ledger) SaveMeta(ty string, id string, m core.Metadata) error {
+	return l.store.SaveMeta(ty, id, m)
+}