go-tools/app/msgbus/service.go

598 lines
13 KiB
Go

package msgbus
import (
"bytes"
"context"
"encoding/base64"
"encoding/json"
"fmt"
"hash/fnv"
"io"
"net/http"
"strconv"
"strings"
"time"
"github.com/gorilla/websocket"
"go.opentelemetry.io/otel/metric"
"go.uber.org/multierr"
"go.sour.is/ev"
"go.sour.is/ev/event"
"go.sour.is/pkg/gql"
"go.sour.is/pkg/lg"
)
type service struct {
es *ev.EventStore
m_gql_posts metric.Int64Counter
m_gql_post_added metric.Int64Counter
m_gql_post_added_event metric.Int64Counter
m_req_time metric.Int64Histogram
}
type MsgbusResolver interface {
Posts(ctx context.Context, name, tag string, paging *gql.PageInput) (*gql.Connection, error)
PostAdded(ctx context.Context, name, tag string, after int64) (<-chan *PostEvent, error)
IsResolver()
}
func New(ctx context.Context, es *ev.EventStore) (*service, error) {
ctx, span := lg.Span(ctx)
defer span.End()
if err := event.Register(ctx, &PostEvent{}); err != nil {
return nil, err
}
if err := event.RegisterName(ctx, "domain.PostEvent", &PostEvent{}); err != nil {
return nil, err
}
m := lg.Meter(ctx)
svc := &service{es: es}
var err, errs error
svc.m_gql_posts, err = m.Int64Counter("msgbus_posts",
metric.WithDescription("msgbus graphql posts requests"),
)
errs = multierr.Append(errs, err)
svc.m_gql_post_added, err = m.Int64Counter("msgbus_post_added",
metric.WithDescription("msgbus graphql post added subcription requests"),
)
errs = multierr.Append(errs, err)
svc.m_gql_post_added_event, err = m.Int64Counter("msgbus_post_event",
metric.WithDescription("msgbus graphql post added subscription events"),
)
errs = multierr.Append(errs, err)
svc.m_req_time, err = m.Int64Histogram("msgbus_request_time",
metric.WithDescription("msgbus graphql post added subscription events"),
metric.WithUnit("ns"),
)
errs = multierr.Append(errs, err)
span.RecordError(err)
return svc, errs
}
var upgrader = websocket.Upgrader{
WriteBufferSize: 4096,
CheckOrigin: func(r *http.Request) bool {
return true
},
}
func (s *service) IsResolver() {}
func (s *service) RegisterHTTP(mux *http.ServeMux) {
mux.Handle("/inbox/", lg.Htrace(http.StripPrefix("/inbox/", s), "inbox"))
}
func (s *service) ServeHTTP(w http.ResponseWriter, r *http.Request) {
ctx := r.Context()
ctx, span := lg.Span(ctx)
defer span.End()
r = r.WithContext(ctx)
switch r.Method {
case http.MethodGet:
if r.Header.Get("Upgrade") == "websocket" {
s.websocket(w, r)
return
}
s.get(w, r)
case http.MethodPost, http.MethodPut:
s.post(w, r)
default:
w.WriteHeader(http.StatusMethodNotAllowed)
}
}
// Posts is the resolver for the events field.
func (s *service) Posts(ctx context.Context, name, tag string, paging *gql.PageInput) (*gql.Connection, error) {
ctx, span := lg.Span(ctx)
defer span.End()
s.m_gql_posts.Add(ctx, 1)
start := time.Now()
defer s.m_req_time.Record(ctx, time.Since(start).Milliseconds())
streamID := withTag("post-"+name, tag)
lis, err := s.es.Read(ctx, streamID, paging.GetIdx(0), paging.GetCount(30))
if err != nil {
span.RecordError(err)
return nil, err
}
edges := make([]gql.Edge, 0, len(lis))
for i := range lis {
span.AddEvent(fmt.Sprint("post ", i, " of ", len(lis)))
e := lis[i]
post, ok := e.(*PostEvent)
if !ok {
continue
}
edges = append(edges, post)
}
var first, last uint64
if first, err = s.es.FirstIndex(ctx, streamID); err != nil {
span.RecordError(err)
return nil, err
}
if last, err = s.es.LastIndex(ctx, streamID); err != nil {
span.RecordError(err)
return nil, err
}
return &gql.Connection{
Paging: &gql.PageInfo{
Next: lis.Last().EventMeta().Position < last,
Prev: lis.First().EventMeta().Position > first,
Begin: lis.First().EventMeta().Position,
End: lis.Last().EventMeta().Position,
},
Edges: edges,
}, nil
}
func (r *service) PostAdded(ctx context.Context, name, tag string, after int64) (<-chan *PostEvent, error) {
ctx, span := lg.Span(ctx)
defer span.End()
r.m_gql_post_added.Add(ctx, 1)
es := r.es.EventStream()
if es == nil {
return nil, fmt.Errorf("EventStore does not implement streaming")
}
streamID := withTag("post-"+name, tag)
sub, err := es.Subscribe(ctx, streamID, after)
if err != nil {
span.RecordError(err)
return nil, err
}
ch := make(chan *PostEvent)
go func() {
ctx, span := lg.Span(ctx)
defer span.End()
{
ctx, span := lg.Fork(ctx)
defer func() {
defer span.End()
ctx, cancel := context.WithTimeout(ctx, 1*time.Second)
defer cancel()
err := sub.Close(ctx)
span.RecordError(err)
}()
}
for <-sub.Recv(ctx) {
events, err := sub.Events(ctx)
if err != nil {
span.RecordError(err)
break
}
span.AddEvent(fmt.Sprintf("received %d events", len(events)))
r.m_gql_post_added_event.Add(ctx, int64(len(events)))
for _, e := range events {
if p, ok := e.(*PostEvent); ok {
select {
case ch <- p:
continue
case <-ctx.Done():
return
}
}
}
}
}()
return ch, nil
}
func (s *service) get(w http.ResponseWriter, r *http.Request) {
ctx := r.Context()
ctx, span := lg.Span(ctx)
defer span.End()
start := time.Now()
defer s.m_req_time.Record(ctx, time.Since(start).Milliseconds())
name, tag, _ := strings.Cut(r.URL.Path, "/")
if name == "" {
w.WriteHeader(http.StatusNotFound)
return
}
streamID := withTag("post-"+name, tag)
var first event.Event = event.NilEvent
if lis, err := s.es.Read(ctx, streamID, 0, 1); err == nil && len(lis) > 0 {
first = lis[0]
}
var pos, count int64 = 0, ev.AllEvents
qry := r.URL.Query()
if i, err := strconv.ParseInt(qry.Get("index"), 10, 64); err == nil && i > 1 {
pos = i - 1
}
if i, err := strconv.ParseInt(qry.Get("pos"), 10, 64); err == nil {
pos = i
}
if i, err := strconv.ParseInt(qry.Get("n"), 10, 64); err == nil {
count = i
}
span.AddEvent(fmt.Sprint("GET topic=", streamID, " idx=", pos, " n=", count))
events, err := s.es.Read(ctx, streamID, pos, count)
if err != nil {
span.RecordError(err)
w.WriteHeader(http.StatusInternalServerError)
return
}
if strings.Contains(r.Header.Get("Accept"), "application/json") {
w.Header().Add("Content-Type", "application/json")
if err = encodeJSON(w, first, events...); err != nil {
span.RecordError(err)
w.WriteHeader(http.StatusInternalServerError)
return
}
return
}
for i := range events {
fmt.Fprintln(w, events[i])
}
}
func (s *service) post(w http.ResponseWriter, r *http.Request) {
ctx := r.Context()
ctx, span := lg.Span(ctx)
defer span.End()
start := time.Now()
defer s.m_req_time.Record(ctx, time.Since(start).Milliseconds())
name, tags, _ := strings.Cut(r.URL.Path, "/")
if name == "" {
w.WriteHeader(http.StatusNotFound)
return
}
var first event.Event = event.NilEvent
if lis, err := s.es.Read(ctx, "post-"+name, 0, 1); err == nil && len(lis) > 0 {
first = lis[0]
}
b, err := io.ReadAll(io.LimitReader(r.Body, 64*1024))
if err != nil {
span.RecordError(err)
w.WriteHeader(http.StatusBadRequest)
return
}
r.Body.Close()
if name == "" {
w.WriteHeader(http.StatusNotFound)
return
}
events := event.NewEvents(&PostEvent{
payload: b,
tags: fields(tags),
})
_, err = s.es.Append(ctx, "post-"+name, events)
if err != nil {
span.RecordError(err)
w.WriteHeader(http.StatusInternalServerError)
return
}
if first == event.NilEvent {
first = events.First()
}
m := events.First().EventMeta()
span.AddEvent(fmt.Sprint("POST topic=", name, " tags=", tags, " idx=", m.Position, " id=", m.EventID))
w.WriteHeader(http.StatusAccepted)
if strings.Contains(r.Header.Get("Accept"), "application/json") {
w.Header().Add("Content-Type", "application/json")
if err = encodeJSON(w, first, events...); err != nil {
span.RecordError(err)
w.WriteHeader(http.StatusInternalServerError)
return
}
return
}
span.AddEvent("finish response")
w.Header().Add("Content-Type", "text/plain")
fmt.Fprintf(w, "OK %d %s", m.Position, m.EventID)
}
func (s *service) websocket(w http.ResponseWriter, r *http.Request) {
ctx := r.Context()
ctx, span := lg.Span(ctx)
defer span.End()
name, tag, _ := strings.Cut(r.URL.Path, "/")
if name == "" {
w.WriteHeader(http.StatusNotFound)
return
}
streamID := withTag("post-"+name, tag)
var first event.Event = event.NilEvent
if lis, err := s.es.Read(ctx, streamID, 0, 1); err == nil && len(lis) > 0 {
first = lis[0]
}
var pos int64 = 0
qry := r.URL.Query()
if i, err := strconv.ParseInt(qry.Get("index"), 10, 64); err == nil && i > 0 {
pos = i - 1
}
span.AddEvent(fmt.Sprint("WS topic=", streamID, " idx=", pos))
c, err := upgrader.Upgrade(w, r, nil)
if err != nil {
span.RecordError(err)
return
}
defer c.Close()
ctx, cancel := context.WithCancel(ctx)
c.SetCloseHandler(func(code int, text string) error {
cancel()
return nil
})
go func() {
for {
if err := ctx.Err(); err != nil {
return
}
mt, message, err := c.ReadMessage()
if err != nil {
span.RecordError(err)
return
}
span.AddEvent(fmt.Sprintf("recv: %d %s", mt, message))
}
}()
es := s.es.EventStream()
if es == nil {
span.AddEvent("EventStore does not implement streaming")
w.WriteHeader(http.StatusInternalServerError)
return
}
sub, err := es.Subscribe(ctx, streamID, pos)
if err != nil {
span.RecordError(err)
return
}
{
ctx, span := lg.Fork(ctx)
defer func() {
defer span.End()
ctx, cancel := context.WithTimeout(ctx, 1*time.Second)
defer cancel()
err := sub.Close(ctx)
span.RecordError(err)
}()
}
span.AddEvent("start ws")
for <-sub.Recv(ctx) {
events, err := sub.Events(ctx)
if err != nil {
break
}
span.AddEvent(fmt.Sprint("got events ", len(events)))
for i := range events {
e, ok := events[i].(*PostEvent)
if !ok {
continue
}
span.AddEvent(fmt.Sprint("send", i, e.String()))
var b bytes.Buffer
if err = encodeJSON(&b, first, e); err != nil {
span.RecordError(err)
}
err = c.WriteMessage(websocket.TextMessage, b.Bytes())
if err != nil {
span.RecordError(err)
break
}
}
}
}
type PostEvent struct {
payload []byte
tags []string
event.IsEvent
}
func (e *PostEvent) Values() any {
if e == nil {
return nil
}
return struct {
Payload []byte `json:"payload"`
Tags []string `json:"tags,omitempty"`
}{
Payload: e.payload,
Tags: e.tags,
}
}
func (e *PostEvent) MarshalBinary() ([]byte, error) {
j := e.Values()
return json.Marshal(&j)
}
func (e *PostEvent) UnmarshalBinary(b []byte) error {
j := struct {
Payload []byte
Tags []string
}{}
err := json.Unmarshal(b, &j)
e.payload = j.Payload
e.tags = j.Tags
return err
}
func (e *PostEvent) MarshalJSON() ([]byte, error) { return e.MarshalBinary() }
func (e *PostEvent) UnmarshalJSON(b []byte) error { return e.UnmarshalBinary(b) }
func (e *PostEvent) ID() string { return e.EventMeta().GetEventID() }
func (e *PostEvent) Tags() []string { return e.tags }
func (e *PostEvent) Payload() string { return string(e.payload) }
func (e *PostEvent) PayloadJSON(ctx context.Context) (m map[string]interface{}, err error) {
err = json.Unmarshal([]byte(e.payload), &m)
return
}
func (e *PostEvent) Meta() event.Meta { return e.EventMeta() }
func (e *PostEvent) IsEdge() {}
func (e *PostEvent) String() string {
var b bytes.Buffer
b.WriteString(strconv.FormatUint(e.EventMeta().Position, 10))
b.WriteRune('\t')
b.WriteString(e.EventMeta().EventID.String())
b.WriteRune('\t')
b.WriteString(string(e.payload))
if len(e.tags) > 0 {
b.WriteRune('\t')
b.WriteString(strings.Join(e.tags, ","))
}
return b.String()
}
func fields(s string) []string {
if s == "" {
return nil
}
return strings.Split(s, ";")
}
func encodeJSON(w io.Writer, first event.Event, events ...event.Event) error {
out := make([]struct {
ID uint64 `json:"id"`
Payload []byte `json:"payload"`
Created string `json:"created"`
Tags []string `json:"tags"`
Topic struct {
Name string `json:"name"`
TTL uint64 `json:"ttl"`
Seq uint64 `json:"seq"`
Created string `json:"created"`
} `json:"topic"`
}, len(events))
for i := range events {
e, ok := events[i].(*PostEvent)
if !ok {
continue
}
out[i].ID = e.EventMeta().Position
out[i].Created = e.EventMeta().Created().Format(time.RFC3339Nano)
out[i].Payload = e.payload
out[i].Tags = e.tags
out[i].Topic.Name = strings.TrimPrefix(e.EventMeta().StreamID, "post-")
out[i].Topic.Created = first.EventMeta().Created().Format(time.RFC3339Nano)
out[i].Topic.Seq = e.EventMeta().Position
}
if len(out) == 1 {
return json.NewEncoder(w).Encode(out[0])
}
return json.NewEncoder(w).Encode(out)
}
func Projector(e event.Event) []event.Event {
m := e.EventMeta()
streamID := m.StreamID
streamPos := m.Position
switch e := e.(type) {
case *PostEvent:
lis := make([]event.Event, len(e.tags))
for i := range lis {
tag := e.tags[i]
ne := event.NewPtr(streamID, streamPos)
event.SetStreamID(withTag(streamID, tag), ne)
lis[i] = ne
}
return lis
}
return nil
}
func withTag(id, tag string) string {
if tag == "" {
return id
}
h := fnv.New128a()
fmt.Fprint(h, tag)
return id + "-" + base64.RawURLEncoding.EncodeToString(h.Sum(nil))
}