/
graphql.go
222 lines (181 loc) · 5.05 KB
/
graphql.go
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package graphql
import (
"context"
"encoding/json"
"errors"
"net/http"
"sync"
"github.com/graphql-go/graphql"
"github.com/jexia/semaphore/pkg/broker"
"github.com/jexia/semaphore/pkg/broker/logger"
"github.com/jexia/semaphore/pkg/codec"
"github.com/jexia/semaphore/pkg/references"
"github.com/jexia/semaphore/pkg/specs"
"github.com/jexia/semaphore/pkg/specs/template"
"github.com/jexia/semaphore/pkg/transport"
"go.uber.org/zap"
)
// Schema base
var (
QueryObject = "query"
MutationObject = "mutation"
)
type req struct {
Query string `json:"query"`
}
// NewListener constructs a new listener for the given addr
func NewListener(addr string, opts specs.Options) transport.NewListener {
return func(parent *broker.Context) transport.Listener {
module := broker.WithModule(parent, "listener", "graphql")
ctx := logger.WithLogger(module)
return &Listener{
ctx: ctx,
server: &http.Server{
Addr: addr,
},
}
}
}
// Listener represents a GraphQL listener
type Listener struct {
ctx *broker.Context
schema graphql.Schema
mutex sync.RWMutex
server *http.Server
}
// Name returns the name of the given listener
func (listener *Listener) Name() string {
return "graphql"
}
// Schema returns the schema of the given listner
func (listener *Listener) Schema() graphql.Schema {
return listener.schema
}
// Serve opens the GraphQL listener and calls the given handler function on reach request
func (listener *Listener) Serve() error {
listener.server.Handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
listener.mutex.RLock()
defer listener.mutex.RUnlock()
req := req{}
json.NewDecoder(r.Body).Decode(&req)
defer r.Body.Close()
result := graphql.Do(graphql.Params{
Schema: listener.schema,
RequestString: req.Query,
})
json.NewEncoder(w).Encode(result)
})
logger.Info(listener.ctx, "serving GraphQL listener", zap.String("addr", listener.server.Addr))
err := listener.server.ListenAndServe()
if err == http.ErrServerClosed {
return nil
}
return err
}
// Handle parses the given endpoints and constructs route handlers
func (listener *Listener) Handle(ctx *broker.Context, endpoints []*transport.Endpoint, constructors map[string]codec.Constructor) error {
if len(endpoints) == 0 {
listener.mutex.Lock()
listener.schema = graphql.Schema{}
listener.mutex.Unlock()
return nil
}
objects := NewObjects()
fields := map[string]graphql.Fields{
QueryObject: {},
MutationObject: {},
}
for _, endpoint := range endpoints {
options, err := ParseEndpointOptions(endpoint)
if err != nil {
return err
}
err = endpoint.NewCodec(ctx, nil, nil)
if err != nil {
return err
}
resolve := func(endpoint *transport.Endpoint) graphql.FieldResolveFn {
return func(p graphql.ResolveParams) (interface{}, error) {
store := endpoint.Flow.NewStore()
ctx := context.Background()
store.Store(template.ResourcePath(template.InputResource), &references.Reference{Value: p.Args})
err = endpoint.Flow.Do(ctx, store)
if err != nil {
object := endpoint.Errs.Get(transport.Unwrap(err))
if object == nil {
logger.Error(listener.ctx, "unable to lookup error manager", zap.Error(err))
return nil, err
}
message := object.ResolveMessage(store)
return nil, errors.New(message)
}
if endpoint.Response == nil || endpoint.Response.Definition == nil {
return make(map[string]interface{}), nil
}
tracker := references.NewTracker()
result, err := ResponseObject(endpoint.Response.Definition.Property, store, tracker)
if err != nil {
return nil, err
}
return result, nil
}
}(endpoint)
res, err := NewSchemaObject(objects, options.Name, endpoint.Response)
if err != nil {
return err
}
path := options.Path
field := &graphql.Field{
Args: graphql.FieldConfigArgument{},
Resolve: resolve,
Type: res,
}
if endpoint.Request != nil {
req, err := NewArgs(endpoint.Request.Definition)
if err != nil {
return err
}
field.Args = req
if endpoint.Request.Definition != nil && endpoint.Request.Definition.Property != nil {
field.Description = endpoint.Request.Definition.Property.Description
}
}
if options.Base == QueryObject && field.Type == nil {
options.Base = MutationObject
}
err = SetField(path, fields[options.Base], field)
if err != nil {
return err
}
}
config := graphql.SchemaConfig{}
if len(fields[MutationObject]) > 0 {
config.Mutation = graphql.NewObject(
graphql.ObjectConfig{
Name: MutationObject,
Fields: fields[MutationObject],
},
)
}
if len(fields[QueryObject]) > 0 {
config.Query = graphql.NewObject(
graphql.ObjectConfig{
Name: QueryObject,
Fields: fields[QueryObject],
},
)
}
schema, err := graphql.NewSchema(config)
if err != nil {
return err
}
listener.mutex.Lock()
listener.schema = schema
listener.mutex.Unlock()
return nil
}
// Close closes the given listener
func (listener *Listener) Close() error {
logger.Info(listener.ctx, "closing GraphQL listener")
return listener.server.Close()
}