HTTP API: support query the DDL history (pingcap#6245)

server/http_handler.go

@@ -34,6 +34,7 @@ import (
 	"github.com/pingcap/tidb/domain"
 	"github.com/pingcap/tidb/infoschema"
 	"github.com/pingcap/tidb/kv"
+	"github.com/pingcap/tidb/meta"
 	"github.com/pingcap/tidb/model"
 	"github.com/pingcap/tidb/session"
 	"github.com/pingcap/tidb/sessionctx"
@@ -66,6 +67,7 @@ const (
 
 // For query string
 const qTableID = "table_id"
+const qLimit = "limit"
 
 const (
 	headerContentType = "Content-Type"
@@ -273,6 +275,31 @@ func (t *tikvHandlerTool) handleMvccGetByHex(params map[string]string) (interfac
 	return t.getMvccByEncodedKey(encodedKey)
 }
 
+func (t *tikvHandlerTool) getAllHistoryDDL() ([]*model.Job, error) {
+	s, err := session.CreateSession(t.store.(kv.Storage))
+	if err != nil {
+		return nil, errors.Trace(err)
+	}
+
+	if s != nil {
+		defer s.Close()
+	}
+
+	store := domain.GetDomain(s.(sessionctx.Context)).Store()
+	txn, err := store.Begin()
+
+	if err != nil {
+		return nil, errors.Trace(err)
+	}
+	txnMeta := meta.NewMeta(txn)
+
+	jobs, err := txnMeta.GetAllHistoryDDLJobs()
+	if err != nil {
+		return nil, errors.Trace(err)
+	}
+	return jobs, nil
+}
+
 // settingsHandler is the handler for list tidb server settings.
 type settingsHandler struct {
 }
@@ -294,6 +321,11 @@ type tableHandler struct {
 	op string
 }
 
+// ddlHistoryJobHandler is the handler for list job history.
+type ddlHistoryJobHandler struct {
+	*tikvHandlerTool
+}
+
 // valueHandle is the handler for get value.
 type valueHandler struct {
 }
@@ -576,6 +608,45 @@ func (h tableHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	}
 }
 
+// ServeHTTP handles request of ddl jobs history.
+func (h ddlHistoryJobHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	if limitID := req.FormValue(qLimit); len(limitID) > 0 {
+		lid, err := strconv.Atoi(limitID)
+
+		if err != nil {
+			writeError(w, err)
+			return
+		}
+
+		if lid < 1 {
+			writeError(w, errors.New("ddl history limit must be greater than 1"))
+			return
+		}
+
+		jobs, err := h.getAllHistoryDDL()
+		if err != nil {
+			writeError(w, errors.New("ddl history not found"))
+			return
+		}
+
+		jobsLen := len(jobs)
+		if jobsLen > lid {
+			start := jobsLen - lid
+			jobs = jobs[start:]
+		}
+
+		writeData(w, jobs)
+		return
+	}
+	jobs, err := h.getAllHistoryDDL()
+	if err != nil {
+		writeError(w, errors.New("ddl history not found"))
+		return
+	}
+	writeData(w, jobs)
+	return
+}
+
 func (h tableHandler) handleRegionRequest(schema infoschema.InfoSchema, tbl table.Table, w http.ResponseWriter, req *http.Request) {
 	tableID := tbl.Meta().ID
 	// for record

server/http_handler_test.go

@@ -28,9 +28,13 @@ import (
 	. "github.com/pingcap/check"
 	"github.com/pingcap/kvproto/pkg/kvrpcpb"
 	"github.com/pingcap/tidb/config"
+	"github.com/pingcap/tidb/domain"
+	"github.com/pingcap/tidb/kv"
+	"github.com/pingcap/tidb/meta"
 	"github.com/pingcap/tidb/model"
 	"github.com/pingcap/tidb/mysql"
 	"github.com/pingcap/tidb/session"
+	"github.com/pingcap/tidb/sessionctx"
 	"github.com/pingcap/tidb/sessionctx/stmtctx"
 	"github.com/pingcap/tidb/store/mockstore"
 	"github.com/pingcap/tidb/store/mockstore/mocktikv"
@@ -547,3 +551,30 @@ func (ts *HTTPHandlerTestSuite) TestGetSchema(c *C) {
 	_, err = http.Get(fmt.Sprintf("http://127.0.0.1:10090/schema/tidb/abc"))
 	c.Assert(err, IsNil)
 }
+
+func (ts *HTTPHandlerTestSuite) TestAllHistory(c *C) {
+	ts.startServer(c)
+	ts.prepareData(c)
+	defer ts.stopServer(c)
+	resp, err := http.Get(fmt.Sprintf("http://127.0.0.1:10090/ddl/history/?limit=3"))
+	c.Assert(err, IsNil)
+	resp, err = http.Get(fmt.Sprintf("http://127.0.0.1:10090/ddl/history/?limit=-1"))
+	c.Assert(err, IsNil)
+
+	resp, err = http.Get(fmt.Sprintf("http://127.0.0.1:10090/ddl/history"))
+	c.Assert(err, IsNil)
+	decoder := json.NewDecoder(resp.Body)
+
+	var jobs []*model.Job
+	s, _ := session.CreateSession(ts.server.newTikvHandlerTool().store.(kv.Storage))
+	defer s.Close()
+	store := domain.GetDomain(s.(sessionctx.Context)).Store()
+	txn, _ := store.Begin()
+	txnMeta := meta.NewMeta(txn)
+	txnMeta.GetAllHistoryDDLJobs()
+	data, _ := txnMeta.GetAllHistoryDDLJobs()
+	err = decoder.Decode(&jobs)
+
+	c.Assert(err, IsNil)
+	c.Assert(jobs, DeepEquals, data)
+}

server/http_status.go

@@ -54,6 +54,7 @@ func (s *Server) startHTTPServer() {
 	router.Handle("/schema/{db}", schemaHandler{tikvHandlerTool})
 	router.Handle("/schema/{db}/{table}", schemaHandler{tikvHandlerTool})
 	router.Handle("/tables/{colID}/{colTp}/{colFlag}/{colLen}", valueHandler{})
+	router.Handle("/ddl/history", ddlHistoryJobHandler{tikvHandlerTool})
 	if s.cfg.Store == "tikv" {
 		// HTTP path for tikv
 		router.Handle("/tables/{db}/{table}/regions", tableHandler{tikvHandlerTool, opTableRegions})