ev/app/gql/resolver.go
2022-09-06 10:35:14 -06:00

133 lines
3.9 KiB
Go

package gql
import (
"context"
"fmt"
"net/http"
"os"
"reflect"
"runtime/debug"
"github.com/99designs/gqlgen/graphql/handler"
"github.com/ravilushqa/otelgqlgen"
"github.com/sour-is/ev/app/gql/playground"
"github.com/sour-is/ev/app/msgbus"
"github.com/sour-is/ev/app/salty"
"github.com/sour-is/ev/internal/graph/generated"
"github.com/sour-is/ev/internal/lg"
"github.com/sour-is/ev/pkg/es"
"github.com/sour-is/ev/pkg/gql"
"github.com/vektah/gqlparser/v2/gqlerror"
)
type Resolver struct {
msgbus.MsgbusResolver
salty.SaltyResolver
es.EventResolver
}
func New(ctx context.Context, resolvers ...interface{ RegisterHTTP(*http.ServeMux) }) (*Resolver, error) {
_, span := lg.Span(ctx)
defer span.End()
r := &Resolver{}
v := reflect.ValueOf(r)
v = reflect.Indirect(v)
noop := reflect.ValueOf(&noop{})
outer:
for _, idx := range reflect.VisibleFields(v.Type()) {
field := v.FieldByIndex(idx.Index)
for i := range resolvers {
rs := reflect.ValueOf(resolvers[i])
if field.IsNil() && rs.Type().Implements(field.Type()) {
span.AddEvent(fmt.Sprint("found ", field.Type().Name()))
field.Set(rs)
continue outer
}
}
span.AddEvent(fmt.Sprint("default ", field.Type().Name()))
field.Set(noop)
}
return r, nil
}
// Query returns generated.QueryResolver implementation.
func (r *Resolver) Query() generated.QueryResolver { return r }
// Query returns generated.QueryResolver implementation.
func (r *Resolver) Mutation() generated.MutationResolver { return r }
// Subscription returns generated.SubscriptionResolver implementation.
func (r *Resolver) Subscription() generated.SubscriptionResolver { return r }
// ChainMiddlewares will check all embeded resolvers for a GetMiddleware func and add to handler.
func (r *Resolver) ChainMiddlewares(h http.Handler) http.Handler {
v := reflect.ValueOf(r) // Get reflected value of *Resolver
v = reflect.Indirect(v) // Get the pointed value (returns a zero value on nil)
n := v.NumField() // Get number of fields to iterate over.
for i := 0; i < n; i++ {
f := v.Field(i)
if !f.CanInterface() { // Skip non-interface types.
continue
}
if iface, ok := f.Interface().(interface {
GetMiddleware() func(http.Handler) http.Handler
}); ok {
h = iface.GetMiddleware()(h) // Append only items that fulfill the interface.
}
}
return h
}
func (r *Resolver) RegisterHTTP(mux *http.ServeMux) {
gql := handler.NewDefaultServer(generated.NewExecutableSchema(generated.Config{Resolvers: r}))
gql.SetRecoverFunc(NoopRecover)
gql.Use(otelgqlgen.Middleware())
mux.Handle("/", playground.Handler("GraphQL playground", "/gql"))
mux.Handle("/gql", lg.Htrace(r.ChainMiddlewares(gql), "gql"))
}
type noop struct{}
func NoopRecover(ctx context.Context, err interface{}) error {
if err, ok := err.(string); ok && err == "not implemented" {
return gqlerror.Errorf("not implemented")
}
fmt.Fprintln(os.Stderr, err)
fmt.Fprintln(os.Stderr)
debug.PrintStack()
return gqlerror.Errorf("internal system error")
}
var _ msgbus.MsgbusResolver = (*noop)(nil)
var _ salty.SaltyResolver = (*noop)(nil)
var _ es.EventResolver = (*noop)(nil)
func (*noop) CreateSaltyUser(ctx context.Context, nick string, pubkey string) (*salty.SaltyUser, error) {
panic("not implemented")
}
func (*noop) Posts(ctx context.Context, streamID string, paging *gql.PageInput) (*gql.Connection, error) {
panic("not implemented")
}
func (*noop) SaltyUser(ctx context.Context, nick string) (*salty.SaltyUser, error) {
panic("not implemented")
}
func (*noop) PostAdded(ctx context.Context, streamID string, after int64) (<-chan *msgbus.PostEvent, error) {
panic("not implemented")
}
func (*noop) Events(ctx context.Context, streamID string, paging *gql.PageInput) (*gql.Connection, error) {
panic("not implemented")
}
func (*noop) EventAdded(ctx context.Context, streamID string, after int64) (<-chan *es.GQLEvent, error) {
panic("not implemented")
}
func (*noop) RegisterHTTP(*http.ServeMux) {}