Merge pull request #435 from Zarkopafilis/show-create-table

sql: plan: Add SHOW CREATE TABLE [Fix #406]

go.mod

@@ -1,56 +1,57 @@
 module gopkg.in/src-d/go-mysql-server.v0
 
 require (
-        github.com/BurntSushi/toml v0.3.1 // indirect
-        github.com/CAFxX/gcnotifier v0.0.0-20170518020117-39b0596a2da3 // indirect
-        github.com/DataDog/datadog-go v0.0.0-20180822151419-281ae9f2d895 // indirect
-        github.com/StackExchange/wmi v0.0.0-20180725035823-b12b22c5341f // indirect
-        github.com/armon/go-metrics v0.0.0-20180917152333-f0300d1749da // indirect
-        github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973 // indirect
+	github.com/BurntSushi/toml v0.3.1 // indirect
+	github.com/CAFxX/gcnotifier v0.0.0-20170518020117-39b0596a2da3 // indirect
+	github.com/DataDog/datadog-go v0.0.0-20180822151419-281ae9f2d895 // indirect
+	github.com/StackExchange/wmi v0.0.0-20180725035823-b12b22c5341f // indirect
+	github.com/armon/go-metrics v0.0.0-20180917152333-f0300d1749da // indirect
+	github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973 // indirect
 	github.com/boltdb/bolt v1.3.1
 	github.com/cespare/xxhash v1.1.0 // indirect
-        github.com/circonus-labs/circonus-gometrics v2.2.4+incompatible // indirect
-        github.com/circonus-labs/circonusllhist v0.0.0-20180430145027-5eb751da55c6 // indirect
-        github.com/go-ole/go-ole v1.2.1 // indirect
+	github.com/circonus-labs/circonus-gometrics v2.2.4+incompatible // indirect
+	github.com/circonus-labs/circonusllhist v0.0.0-20180430145027-5eb751da55c6 // indirect
+	github.com/go-ole/go-ole v1.2.1 // indirect
 	github.com/gogo/protobuf v1.1.1 // indirect
-        github.com/google/go-cmp v0.2.0 // indirect
-        github.com/gorilla/context v1.1.1 // indirect
-        github.com/gorilla/handlers v1.4.0 // indirect
-        github.com/gorilla/mux v1.6.2 // indirect
-        github.com/hashicorp/consul v1.2.3 // indirect
-        github.com/hashicorp/go-cleanhttp v0.5.0 // indirect
-        github.com/hashicorp/go-immutable-radix v1.0.0 // indirect
-        github.com/hashicorp/go-msgpack v0.0.0-20150518234257-fa3f63826f7c // indirect
-        github.com/hashicorp/go-multierror v1.0.0 // indirect
-        github.com/hashicorp/go-retryablehttp v0.0.0-20180718195005-e651d75abec6 // indirect
-        github.com/hashicorp/go-sockaddr v0.0.0-20180320115054-6d291a969b86 // indirect
-        github.com/hashicorp/memberlist v0.1.0 // indirect
-        github.com/hashicorp/serf v0.8.1 // indirect
-        github.com/hashicorp/yamux v0.0.0-20180917205041-7221087c3d28 // indirect
-        github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
-        github.com/miekg/dns v1.0.12 // indirect
+	github.com/google/go-cmp v0.2.0 // indirect
+	github.com/gorilla/context v1.1.1 // indirect
+	github.com/gorilla/handlers v1.4.0 // indirect
+	github.com/gorilla/mux v1.6.2 // indirect
+	github.com/hashicorp/consul v1.2.3 // indirect
+	github.com/hashicorp/go-cleanhttp v0.5.0 // indirect
+	github.com/hashicorp/go-immutable-radix v1.0.0 // indirect
+	github.com/hashicorp/go-msgpack v0.0.0-20150518234257-fa3f63826f7c // indirect
+	github.com/hashicorp/go-multierror v1.0.0 // indirect
+	github.com/hashicorp/go-retryablehttp v0.0.0-20180718195005-e651d75abec6 // indirect
+	github.com/hashicorp/go-sockaddr v0.0.0-20180320115054-6d291a969b86 // indirect
+	github.com/hashicorp/memberlist v0.1.0 // indirect
+	github.com/hashicorp/serf v0.8.1 // indirect
+	github.com/hashicorp/yamux v0.0.0-20180917205041-7221087c3d28 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
+	github.com/miekg/dns v1.0.12 // indirect
 	github.com/mitchellh/hashstructure v1.0.0
+	github.com/oliveagle/jsonpath v0.0.0-20180606110733-2e52cf6e6852
 	github.com/opentracing/opentracing-go v1.0.2
-        github.com/pascaldekloe/goe v0.0.0-20180627143212-57f6aae5913c // indirect
-        github.com/pelletier/go-toml v1.2.0 // indirect
+	github.com/pascaldekloe/goe v0.0.0-20180627143212-57f6aae5913c // indirect
+	github.com/pelletier/go-toml v1.2.0 // indirect
 	github.com/pilosa/pilosa v1.1.0
 	github.com/pkg/errors v0.8.0 // indirect
-        github.com/prometheus/client_golang v0.8.0 // indirect
-        github.com/prometheus/client_model v0.0.0-20180712105110-5c3871d89910 // indirect
-        github.com/prometheus/common v0.0.0-20180801064454-c7de2306084e // indirect
-        github.com/prometheus/procfs v0.0.0-20180920065004-418d78d0b9a7 // indirect
+	github.com/prometheus/client_golang v0.8.0 // indirect
+	github.com/prometheus/client_model v0.0.0-20180712105110-5c3871d89910 // indirect
+	github.com/prometheus/common v0.0.0-20180801064454-c7de2306084e // indirect
+	github.com/prometheus/procfs v0.0.0-20180920065004-418d78d0b9a7 // indirect
 	github.com/satori/go.uuid v1.2.0 // indirect
-        github.com/sean-/seed v0.0.0-20170313163322-e2103e2c3529 // indirect
-        github.com/shirou/gopsutil v2.17.12+incompatible // indirect
-        github.com/shirou/w32 v0.0.0-20160930032740-bb4de0191aa4 // indirect
+	github.com/sean-/seed v0.0.0-20170313163322-e2103e2c3529 // indirect
+	github.com/shirou/gopsutil v2.17.12+incompatible // indirect
+	github.com/shirou/w32 v0.0.0-20160930032740-bb4de0191aa4 // indirect
 	github.com/sirupsen/logrus v1.1.0
 	github.com/spf13/cast v1.2.0
 	github.com/stretchr/testify v1.2.2
-        github.com/tv42/httpunix v0.0.0-20150427012821-b75d8614f926 // indirect
-	      golang.org/x/net v0.0.0-20180926154720-4dfa2610cdf3 // indirect
+	github.com/tv42/httpunix v0.0.0-20150427012821-b75d8614f926 // indirect
+	golang.org/x/net v0.0.0-20180926154720-4dfa2610cdf3 // indirect
 	google.golang.org/grpc v1.15.0 // indirect
 	gopkg.in/src-d/go-errors.v1 v1.0.0
 	gopkg.in/src-d/go-vitess.v1 v1.1.0
-        gopkg.in/vmihailenco/msgpack.v2 v2.9.1 // indirect
+	gopkg.in/vmihailenco/msgpack.v2 v2.9.1 // indirect
 	gopkg.in/yaml.v2 v2.2.1
 )

sql/analyzer/assign_catalog.go

@@ -34,6 +34,11 @@ func assignCatalog(ctx *sql.Context, a *Analyzer, n sql.Node) (sql.Node, error)
 			nc := *node
 			nc.Catalog = a.Catalog
 			return &nc, nil
+		case *plan.ShowCreateTable:
+			nc := *node
+			nc.Catalog = a.Catalog
+			nc.CurrentDatabase = a.Catalog.CurrentDatabase()
+			return &nc, nil
 		case *plan.ShowProcessList:
 			nc := *node
 			nc.Database = a.Catalog.CurrentDatabase()

sql/parse/parse.go

@@ -9,13 +9,12 @@ import (
 	"strconv"
 	"strings"
 
-	"gopkg.in/src-d/go-mysql-server.v0/sql/expression/function"
-
-	opentracing "github.com/opentracing/opentracing-go"
+	"github.com/opentracing/opentracing-go"
 	"github.com/sirupsen/logrus"
 	"gopkg.in/src-d/go-errors.v1"
 	"gopkg.in/src-d/go-mysql-server.v0/sql"
 	"gopkg.in/src-d/go-mysql-server.v0/sql/expression"
+	"gopkg.in/src-d/go-mysql-server.v0/sql/expression/function"
 	"gopkg.in/src-d/go-mysql-server.v0/sql/plan"
 	"gopkg.in/src-d/go-vitess.v1/vt/sqlparser"
 )
@@ -39,6 +38,7 @@ var (
 	createIndexRegex     = regexp.MustCompile(`^create\s+index\s+`)
 	dropIndexRegex       = regexp.MustCompile(`^drop\s+index\s+`)
 	showIndexRegex       = regexp.MustCompile(`^show\s+(index|indexes|keys)\s+(from|in)\s+\S+\s*`)
+	showCreateRegex      = regexp.MustCompile(`^show create\s+\S+\s*`)
 	showVariablesRegex   = regexp.MustCompile(`^show\s+(.*)?variables\s*`)
 	describeRegex        = regexp.MustCompile(`^(describe|desc|explain)\s+(.*)\s+`)
 	fullProcessListRegex = regexp.MustCompile(`^show\s+(full\s+)?processlist$`)
@@ -70,6 +70,8 @@ func Parse(ctx *sql.Context, query string) (sql.Node, error) {
 		return parseDropIndex(s)
 	case showIndexRegex.MatchString(lowerQuery):
 		return parseShowIndex(s)
+	case showCreateRegex.MatchString(lowerQuery):
+		return parseShowCreate(s)
 	case showVariablesRegex.MatchString(lowerQuery):
 		return parseShowVariables(ctx, s)
 	case describeRegex.MatchString(lowerQuery):

sql/parse/show_create.go

@@ -0,0 +1,48 @@
+package parse
+
+import (
+	"bufio"
+	"strings"
+)
+
+import (
+	"gopkg.in/src-d/go-errors.v1"
+	"gopkg.in/src-d/go-mysql-server.v0/sql"
+	"gopkg.in/src-d/go-mysql-server.v0/sql/plan"
+)
+
+var errUnsupportedShowCreateQuery = errors.NewKind("Unsupported query: SHOW CREATE %s")
+
+func parseShowCreate(s string) (sql.Node, error) {
+	r := bufio.NewReader(strings.NewReader(s))
+
+	var thingToShow string
+	var name string
+	steps := []parseFunc{
+		expect("show"),
+		skipSpaces,
+		expect("create"),
+		skipSpaces,
+		readIdent(&thingToShow),
+		skipSpaces,
+		readIdent(&name),
+		skipSpaces,
+		checkEOF,
+	}
+
+	for _, step := range steps {
+		if err := step(r); err != nil {
+			return nil, err
+		}
+	}
+
+	switch strings.ToLower(thingToShow) {
+	case "table":
+		return plan.NewShowCreateTable(
+			sql.UnresolvedDatabase("").Name(),
+			nil,
+			name), nil
+	default:
+		return nil, errUnsupportedShowCreateQuery.New(name)
+	}
+}

sql/parse/show_create_test.go

@@ -0,0 +1,56 @@
+package parse
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"gopkg.in/src-d/go-errors.v1"
+	"gopkg.in/src-d/go-mysql-server.v0/sql"
+	"gopkg.in/src-d/go-mysql-server.v0/sql/plan"
+)
+
+func TestParseShowCreateTableQuery(t *testing.T) {
+	testCases := []struct {
+		query  string
+		result sql.Node
+		err    *errors.Kind
+	}{
+		{
+			"SHOW CREATE",
+			nil,
+			errUnsupportedShowCreateQuery,
+		},
+		{
+			"SHOW CREATE ANYTHING",
+			nil,
+			errUnsupportedShowCreateQuery,
+		},
+		{
+			"SHOW CREATE ASDF foo",
+			nil,
+			errUnsupportedShowCreateQuery,
+		},
+		{
+			"SHOW CREATE TABLE mytable",
+			plan.NewShowCreateTable(sql.UnresolvedDatabase("").Name(),
+				nil,
+				"mytable"),
+			nil,
+		},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.query, func(t *testing.T) {
+			require := require.New(t)
+
+			result, err := parseShowCreate(tt.query)
+			if tt.err != nil {
+				require.Error(err)
+				require.True(tt.err.Is(err))
+			} else {
+				require.NoError(err)
+				require.Equal(tt.result, result)
+			}
+		})
+	}
+}

sql/plan/show_create_table.go

@@ -0,0 +1,143 @@
+package plan
+
+import (
+	"fmt"
+	"io"
+	"strings"
+
+	"gopkg.in/src-d/go-errors.v1"
+	"gopkg.in/src-d/go-mysql-server.v0/sql"
+)
+
+var ErrTableNotFound = errors.NewKind("Table `%s` not found")
+
+// ShowCreateTable is a node that shows the CREATE TABLE statement for a table.
+type ShowCreateTable struct {
+	Catalog         *sql.Catalog
+	CurrentDatabase string
+	Table           string
+}
+
+// Schema implements the Node interface.
+func (n *ShowCreateTable) Schema() sql.Schema {
+	return sql.Schema{
+		&sql.Column{Name: "Table", Type: sql.Text, Nullable: false},
+		&sql.Column{Name: "Create Table", Type: sql.Text, Nullable: false},
+	}
+}
+
+// TransformExpressionsUp implements the Transformable interface.
+func (n *ShowCreateTable) TransformExpressionsUp(f sql.TransformExprFunc) (sql.Node, error) {
+	return n, nil
+}
+
+// TransformUp implements the Transformable interface.
+func (n *ShowCreateTable) TransformUp(f sql.TransformNodeFunc) (sql.Node, error) {
+	return f(NewShowCreateTable(n.CurrentDatabase, n.Catalog, n.Table))
+}
+
+// RowIter implements the Node interface
+func (n *ShowCreateTable) RowIter(*sql.Context) (sql.RowIter, error) {
+	db, err := n.Catalog.Database(n.CurrentDatabase)
+
+	if err != nil {
+		return nil, sql.ErrDatabaseNotFound.New(n.CurrentDatabase)
+	}
+
+	return &showCreateTablesIter{
+		db:    db,
+		table: n.Table,
+	}, nil
+}
+
+// String implements the Stringer interface.
+func (n *ShowCreateTable) String() string {
+	return fmt.Sprintf("SHOW CREATE TABLE %s", n.Table)
+}
+
+type createTableStmt struct {
+	colName string
+	colType sql.Type
+}
+
+type showCreateTablesIter struct {
+	db    sql.Database
+	table string
+
+	createStmt   *createTableStmt
+	didIteration bool
+}
+
+func (i *showCreateTablesIter) Next() (sql.Row, error) {
+	if i.didIteration {
+		return nil, io.EOF
+	}
+
+	i.didIteration = true
+
+	table, found := i.db.Tables()[i.table]
+
+	if !found {
+		return nil, ErrTableNotFound.New(i.table)
+	}
+
+	composedCreateTableStatement := produceCreateStatement(table)
+
+	return sql.NewRow(
+		i.table,                      // "Table" string
+		composedCreateTableStatement, // "Create Table" string
+	), nil
+}
+
+func produceCreateStatement(table sql.Table) string {
+	schema := table.Schema()
+	colCreateStatements := make([]string, len(schema), len(schema))
+
+	// Statement creation parts for each column
+	for indx, col := range schema {
+		createStmtPart := fmt.Sprintf("`%s` %s", col.Name, col.Type.Type())
+
+		if !col.Nullable {
+			createStmtPart = fmt.Sprintf("%s NOT NULL", createStmtPart)
+		}
+
+		switch def := col.Default.(type) {
+		case string:
+			if def != "" {
+				createStmtPart = fmt.Sprintf("%s DEFAULT %s", createStmtPart, def)
+			}
+		default:
+			if def != nil {
+				createStmtPart = fmt.Sprintf("%s DEFAULT %v", createStmtPart, col.Default)
+			}
+		}
+
+		colCreateStatements[indx] = createStmtPart
+	}
+
+	prettyColCreateStmts := fmt.Sprintf("%s", strings.Join(colCreateStatements, ",\n"))
+	composedCreateTableStatement :=
+		fmt.Sprintf("CREATE TABLE `%s` (%s) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", table.Name(), prettyColCreateStmts)
+
+	return composedCreateTableStatement
+}
+
+func (i *showCreateTablesIter) Close() error {
+	return nil
+}
+
+// NewShowCreateTable creates a new ShowCreateTable node.
+func NewShowCreateTable(db string, ctl *sql.Catalog, table string) sql.Node {
+	return &ShowCreateTable{
+		CurrentDatabase: db,
+		Table:           table,
+		Catalog:         ctl}
+}
+
+// Resolved implements the Resolvable interface.
+func (n *ShowCreateTable) Resolved() bool {
+	return true
+}
+
+// Children implements the Node interface.
+func (n *ShowCreateTable) Children() []sql.Node { return nil }