Existence Invariants (#27)

.github/workflows/build.yaml

@@ -15,7 +15,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v2
         with:
-          go-version: 1.16
+          go-version: 1.19.x
 
       - name: Install Staticcheck
         run: go install honnef.co/go/tools/cmd/staticcheck@latest
@@ -33,7 +33,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v2
         with:
-          go-version: 1.16
+          go-version: 1.19.x
 
       - name: Checkout Code
         uses: actions/checkout@v2

.github/workflows/release.yaml

@@ -17,7 +17,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v2
         with:
-          go-version: 1.16
+          go-version: 1.19.x
 
       - name: Import GPG key
         id: import_gpg

bench_test.go

@@ -1,7 +1,6 @@
 package honu_test
 
 import (
-	"io/ioutil"
 	"math/rand"
 	"os"
 	"testing"
@@ -21,7 +20,7 @@ var (
 
 func setupLevelDB(t testing.TB) (*leveldb.DB, string) {
 	// Create a new leveldb database in a temporary directory
-	tmpDir, err := ioutil.TempDir("", "leveldb-*")
+	tmpDir, err := os.MkdirTemp("", "leveldb-*")
 	require.NoError(t, err)
 
 	// Open a leveldb database directly without honu wrapper

engines/engine.go

@@ -23,6 +23,7 @@ type Engine interface {
 // Store is a simple key/value interface that allows for Get, Put, and Delete. Nearly
 // all engines should support the Store interface.
 type Store interface {
+	Has(key []byte, options *opts.Options) (exists bool, err error)
 	Get(key []byte, options *opts.Options) (value []byte, err error)
 	Put(key, value []byte, options *opts.Options) error
 	Delete(key []byte, options *opts.Options) error

engines/errors.go

@@ -3,6 +3,7 @@ package engine
 import "errors"
 
 var (
-	ErrNotFound   = errors.New("not found")
-	ErrReadOnlyTx = errors.New("cannot execute a write operation in a read only transaction")
+	ErrNotFound      = errors.New("not found")
+	ErrReadOnlyTx    = errors.New("cannot execute a write operation in a read only transaction")
+	ErrAlreadyExists = errors.New("specified key already exists in the database")
 )

engines/leveldb/leveldb.go

@@ -71,6 +71,35 @@ func (tx *Transaction) Finish() error {
 	return nil
 }
 
+// Has returns true if the DB does contains the given key.
+func (tx *Transaction) Has(key []byte, options *opts.Options) (bool, error) {
+	return tx.db.has(key, options)
+}
+
+// Has returns true if the DB does contains the given key.
+func (db *LevelDBEngine) Has(key []byte, options *opts.Options) (bool, error) {
+	db.RLock()
+	defer db.RUnlock()
+	return db.has(key, options)
+}
+
+// Has returns true if the DB does contains the given key.
+func (db *LevelDBEngine) has(key []byte, options *opts.Options) (_ bool, err error) {
+	// Create a default to prevent panics when accessing options.
+	if options == nil {
+		if options, err = opts.New(); err != nil {
+			return false, err
+		}
+	}
+
+	// Namespaces in leveldb are provided not by buckets but by namespace:: prefixed keys
+	if options.Namespace != "" {
+		key = prepend(options.Namespace, key)
+	}
+
+	return db.ldb.Has(key, options.LevelDBRead)
+}
+
 // Get the latest version of the object stored by the key. This is the Transaction Get
 // method which can be used in either readonly or write modes. This is the preferred
 // mechanism to access the underlying engine.

engines/leveldb/leveldb_test.go

@@ -1,7 +1,6 @@
 package leveldb_test
 
 import (
-	"io/ioutil"
 	"os"
 	"testing"
 
@@ -38,7 +37,7 @@ var testNamespaces = []string{
 
 // Returns a LevelDBEngine and the path where it was created.
 func setupLevelDBEngine(t testing.TB) (_ *leveldb.LevelDBEngine, path string) {
-	tempDir, err := ioutil.TempDir("", "leveldb-*")
+	tempDir, err := os.MkdirTemp("", "leveldb-*")
 	require.NoError(t, err)
 
 	conf, _ := config.New()
@@ -71,6 +70,13 @@ func checkPut(ldbStore engine.Store, opts *options.Options, key []byte, value []
 	require.NoError(t, err)
 }
 
+// Wraps engine.Store.Has with testing checks
+func checkHas(ldbStore engine.Store, opts *options.Options, key []byte, assert require.BoolAssertionFunc, t *testing.T) {
+	exists, err := ldbStore.Has(key, opts)
+	require.NoError(t, err)
+	assert(t, exists)
+}
+
 // Wraps engine.Store.Get with testing checks.
 func checkGet(ldbStore engine.Store, opts *options.Options, key []byte, expectedValue []byte, t *testing.T) {
 	getValue, err := ldbStore.Get(key, opts)
@@ -134,7 +140,9 @@ func TestLevelDBTransactions(t *testing.T) {
 		opts, err := options.New(options.WithNamespace(namespace))
 		require.NoError(t, err)
 		value := []byte(namespace)
+		checkHas(tx, opts, key, require.False, t)
 		checkPut(tx, opts, key, value, t)
+		checkHas(tx, opts, key, require.True, t)
 		checkGet(tx, opts, key, value, t)
 		checkDelete(tx, opts, key, t)
 

go.mod

@@ -1,14 +1,45 @@
 module github.com/rotationalio/honu
 
-go 1.16
+go 1.19
 
 require (
-	github.com/cockroachdb/pebble v0.0.0-20211021161301-9106d5d2238f
-	github.com/gogo/protobuf v1.3.2 // indirect
-	github.com/golang/protobuf v1.5.2
-	github.com/klauspost/compress v1.12.3 // indirect
-	github.com/stretchr/testify v1.6.1
+	github.com/cockroachdb/pebble v0.0.0-20230906203007-2129a6e99d0f
+	github.com/golang/protobuf v1.5.3
+	github.com/stretchr/testify v1.8.4
 	github.com/syndtr/goleveldb v1.0.0
-	google.golang.org/grpc v1.39.0
-	google.golang.org/protobuf v1.27.1
+	google.golang.org/grpc v1.58.0
+	google.golang.org/protobuf v1.31.0
+)
+
+require (
+	github.com/DataDog/zstd v1.5.5 // indirect
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/cespare/xxhash/v2 v2.2.0 // indirect
+	github.com/cockroachdb/errors v1.11.1 // indirect
+	github.com/cockroachdb/logtags v0.0.0-20230118201751-21c54148d20b // indirect
+	github.com/cockroachdb/redact v1.1.5 // indirect
+	github.com/cockroachdb/tokenbucket v0.0.0-20230807174530-cc333fc44b06 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/getsentry/sentry-go v0.24.0 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/golang/snappy v0.0.4 // indirect
+	github.com/klauspost/compress v1.16.7 // indirect
+	github.com/kr/pretty v0.3.1 // indirect
+	github.com/kr/text v0.2.0 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.4 // indirect
+	github.com/onsi/ginkgo v1.13.0 // indirect
+	github.com/onsi/gomega v1.10.1 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/prometheus/client_golang v1.16.0 // indirect
+	github.com/prometheus/client_model v0.4.0 // indirect
+	github.com/prometheus/common v0.44.0 // indirect
+	github.com/prometheus/procfs v0.11.1 // indirect
+	github.com/rogpeppe/go-internal v1.11.0 // indirect
+	golang.org/x/exp v0.0.0-20230905200255-921286631fa9 // indirect
+	golang.org/x/net v0.15.0 // indirect
+	golang.org/x/sys v0.12.0 // indirect
+	golang.org/x/text v0.13.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20230822172742-b8732ec3820d // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )