forked from rancher/norman
/
handler.go
174 lines (148 loc) · 4.01 KB
/
handler.go
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package subscribe
import (
"bytes"
"context"
"errors"
"time"
"github.com/gorilla/websocket"
"github.com/rancher/norman/api/writer"
"github.com/rancher/norman/httperror"
"github.com/rancher/norman/parse"
"github.com/rancher/norman/types"
"github.com/rancher/norman/types/convert"
"github.com/rancher/norman/types/slice"
"github.com/sirupsen/logrus"
"golang.org/x/sync/errgroup"
)
var upgrader = websocket.Upgrader{}
type Subscribe struct {
ResourceTypes []string
APIVersions []string
ProjectID string `norman:"type=reference[/v3/schemas/project]"`
}
func Handler(apiContext *types.APIContext, _ types.RequestHandler) error {
err := handler(apiContext)
if err != nil {
logrus.Errorf("Error during subscribe %v", err)
}
return err
}
func getMatchingSchemas(apiContext *types.APIContext) []*types.Schema {
resourceTypes := apiContext.Request.URL.Query()["resourceTypes"]
var schemas []*types.Schema
for _, schema := range apiContext.Schemas.SchemasForVersion(*apiContext.Version) {
if !matches(resourceTypes, schema.ID) {
continue
}
if schema.Store != nil {
schemas = append(schemas, schema)
}
}
return schemas
}
func handler(apiContext *types.APIContext) error {
schemas := getMatchingSchemas(apiContext)
if len(schemas) == 0 {
return httperror.NewAPIError(httperror.NotFound, "no resources types matched")
}
c, err := upgrader.Upgrade(apiContext.Response, apiContext.Request, nil)
if err != nil {
return err
}
defer c.Close()
cancelCtx, cancel := context.WithCancel(apiContext.Request.Context())
readerGroup, ctx := errgroup.WithContext(cancelCtx)
apiContext.Request = apiContext.Request.WithContext(ctx)
go func() {
for {
if _, _, err := c.NextReader(); err != nil {
cancel()
c.Close()
break
}
}
}()
events := make(chan map[string]interface{})
for _, schema := range schemas {
streamStore(ctx, readerGroup, apiContext, schema, events)
}
go func() {
readerGroup.Wait()
close(events)
}()
jsonWriter := writer.EncodingResponseWriter{
ContentType: "application/json",
Encoder: types.JSONEncoder,
}
t := time.NewTicker(5 * time.Second)
defer t.Stop()
done := false
for !done {
select {
case item, ok := <-events:
if !ok {
done = true
break
}
header := `{"name":"resource.change","data":`
if item[".removed"] == true {
header = `{"name":"resource.remove","data":`
}
schema := apiContext.Schemas.Schema(apiContext.Version, convert.ToString(item["type"]))
if schema != nil {
buffer := &bytes.Buffer{}
if err := jsonWriter.VersionBody(apiContext, &schema.Version, buffer, item); err != nil {
return err
}
if err := writeData(c, header, buffer.Bytes()); err != nil {
return err
}
}
case <-t.C:
if err := writeData(c, `{"name":"ping","data":`, []byte("{}")); err != nil {
return err
}
}
}
// no point in ever returning null because the connection is hijacked and we can't write it
return nil
}
func writeData(c *websocket.Conn, header string, buf []byte) error {
messageWriter, err := c.NextWriter(websocket.TextMessage)
if err != nil {
return err
}
if _, err := messageWriter.Write([]byte(header)); err != nil {
return err
}
if _, err := messageWriter.Write(buf); err != nil {
return err
}
if _, err := messageWriter.Write([]byte(`}`)); err != nil {
return err
}
return messageWriter.Close()
}
func streamStore(ctx context.Context, eg *errgroup.Group, apiContext *types.APIContext, schema *types.Schema, result chan map[string]interface{}) {
eg.Go(func() error {
opts := parse.QueryOptions(apiContext, schema)
events, err := schema.Store.Watch(apiContext, schema, &opts)
if err != nil || events == nil {
if err != nil {
logrus.Errorf("failed on subscribe %s: %v", schema.ID, err)
}
return err
}
logrus.Debugf("watching %s", schema.ID)
for e := range events {
result <- e
}
return errors.New("disconnect")
})
}
func matches(items []string, item string) bool {
if len(items) == 0 {
return true
}
return slice.ContainsString(items, item)
}