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wrapper.go
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wrapper.go
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package wrapper
import (
"context"
"reflect"
"strings"
"github.com/chnkenc/go-micro/auth"
"github.com/chnkenc/go-micro/client"
"github.com/chnkenc/go-micro/debug/stats"
"github.com/chnkenc/go-micro/debug/trace"
"github.com/chnkenc/go-micro/errors"
"github.com/chnkenc/go-micro/metadata"
"github.com/chnkenc/go-micro/server"
)
type fromServiceWrapper struct {
client.Client
// headers to inject
headers metadata.Metadata
}
var (
HeaderPrefix = "Micro-"
)
func (f *fromServiceWrapper) setHeaders(ctx context.Context) context.Context {
// don't overwrite keys
return metadata.MergeContext(ctx, f.headers, false)
}
func (f *fromServiceWrapper) Call(ctx context.Context, req client.Request, rsp interface{}, opts ...client.CallOption) error {
ctx = f.setHeaders(ctx)
return f.Client.Call(ctx, req, rsp, opts...)
}
func (f *fromServiceWrapper) Stream(ctx context.Context, req client.Request, opts ...client.CallOption) (client.Stream, error) {
ctx = f.setHeaders(ctx)
return f.Client.Stream(ctx, req, opts...)
}
func (f *fromServiceWrapper) Publish(ctx context.Context, p client.Message, opts ...client.PublishOption) error {
ctx = f.setHeaders(ctx)
return f.Client.Publish(ctx, p, opts...)
}
// FromService wraps a client to inject service and auth metadata
func FromService(name string, c client.Client) client.Client {
return &fromServiceWrapper{
c,
metadata.Metadata{
HeaderPrefix + "From-Service": name,
},
}
}
// HandlerStats wraps a server handler to generate request/error stats
func HandlerStats(stats stats.Stats) server.HandlerWrapper {
// return a handler wrapper
return func(h server.HandlerFunc) server.HandlerFunc {
// return a function that returns a function
return func(ctx context.Context, req server.Request, rsp interface{}) error {
// execute the handler
err := h(ctx, req, rsp)
// record the stats
stats.Record(err)
// return the error
return err
}
}
}
type traceWrapper struct {
client.Client
name string
trace trace.Tracer
}
func (c *traceWrapper) Call(ctx context.Context, req client.Request, rsp interface{}, opts ...client.CallOption) error {
newCtx, s := c.trace.Start(ctx, req.Service()+"."+req.Endpoint())
s.Type = trace.SpanTypeRequestOutbound
err := c.Client.Call(newCtx, req, rsp, opts...)
if err != nil {
s.Metadata["error"] = err.Error()
}
// finish the trace
c.trace.Finish(s)
return err
}
// TraceCall is a call tracing wrapper
func TraceCall(name string, t trace.Tracer, c client.Client) client.Client {
return &traceWrapper{
name: name,
trace: t,
Client: c,
}
}
// TraceHandler wraps a server handler to perform tracing
func TraceHandler(t trace.Tracer) server.HandlerWrapper {
// return a handler wrapper
return func(h server.HandlerFunc) server.HandlerFunc {
// return a function that returns a function
return func(ctx context.Context, req server.Request, rsp interface{}) error {
// don't store traces for debug
if strings.HasPrefix(req.Endpoint(), "Debug.") {
return h(ctx, req, rsp)
}
// get the span
newCtx, s := t.Start(ctx, req.Service()+"."+req.Endpoint())
s.Type = trace.SpanTypeRequestInbound
err := h(newCtx, req, rsp)
if err != nil {
s.Metadata["error"] = err.Error()
}
// finish
t.Finish(s)
return err
}
}
}
type authWrapper struct {
client.Client
auth func() auth.Auth
}
func (a *authWrapper) Call(ctx context.Context, req client.Request, rsp interface{}, opts ...client.CallOption) error {
// parse the options
var options client.CallOptions
for _, o := range opts {
o(&options)
}
// check to see if the authorization header has already been set.
// We dont't override the header unless the ServiceToken option has
// been specified or the header wasn't provided
if _, ok := metadata.Get(ctx, "Authorization"); ok && !options.ServiceToken {
return a.Client.Call(ctx, req, rsp, opts...)
}
// if auth is nil we won't be able to get an access token, so we execute
// the request without one.
aa := a.auth()
if aa == nil {
return a.Client.Call(ctx, req, rsp, opts...)
}
// set the namespace header if it has not been set (e.g. on a service to service request)
if _, ok := metadata.Get(ctx, "Micro-Namespace"); !ok {
ctx = metadata.Set(ctx, "Micro-Namespace", aa.Options().Namespace)
}
// check to see if we have a valid access token
aaOpts := aa.Options()
if aaOpts.Token != nil && !aaOpts.Token.Expired() {
ctx = metadata.Set(ctx, "Authorization", auth.BearerScheme+aaOpts.Token.AccessToken)
return a.Client.Call(ctx, req, rsp, opts...)
}
// call without an auth token
return a.Client.Call(ctx, req, rsp, opts...)
}
// AuthClient wraps requests with the auth header
func AuthClient(auth func() auth.Auth, c client.Client) client.Client {
return &authWrapper{c, auth}
}
// AuthHandler wraps a server handler to perform auth
func AuthHandler(fn func() auth.Auth) server.HandlerWrapper {
return func(h server.HandlerFunc) server.HandlerFunc {
return func(ctx context.Context, req server.Request, rsp interface{}) error {
// get the auth.Auth interface
a := fn()
// Check for debug endpoints which should be excluded from auth
if strings.HasPrefix(req.Endpoint(), "Debug.") {
return h(ctx, req, rsp)
}
// Extract the token if present. Note: if noop is being used
// then the token can be blank without erroring
var account *auth.Account
if header, ok := metadata.Get(ctx, "Authorization"); ok {
// Ensure the correct scheme is being used
if !strings.HasPrefix(header, auth.BearerScheme) {
return errors.Unauthorized(req.Service(), "invalid authorization header. expected Bearer schema")
}
// Strip the prefix and inspect the resulting token
account, _ = a.Inspect(strings.TrimPrefix(header, auth.BearerScheme))
}
// Extract the namespace header
ns, ok := metadata.Get(ctx, "Micro-Namespace")
if !ok {
ns = a.Options().Namespace
ctx = metadata.Set(ctx, "Micro-Namespace", ns)
}
// Check the issuer matches the services namespace. TODO: Stop allowing go.micro to access
// any namespace and instead check for the server issuer.
if account != nil && account.Issuer != ns && account.Issuer != "go.micro" {
return errors.Forbidden(req.Service(), "Account was not issued by %v", ns)
}
// construct the resource
res := &auth.Resource{
Type: "service",
Name: req.Service(),
Endpoint: req.Endpoint(),
}
// Verify the caller has access to the resource
err := a.Verify(account, res, auth.VerifyContext(ctx))
if err != nil && account != nil {
return errors.Forbidden(req.Service(), "Forbidden call made to %v:%v by %v", req.Service(), req.Endpoint(), account.ID)
} else if err != nil {
return errors.Unauthorized(req.Service(), "Unauthorized call made to %v:%v", req.Service(), req.Endpoint())
}
// There is an account, set it in the context
if account != nil {
ctx = auth.ContextWithAccount(ctx, account)
}
// The user is authorised, allow the call
return h(ctx, req, rsp)
}
}
}
type cacheWrapper struct {
cacheFn func() *client.Cache
client.Client
}
// Call executes the request. If the CacheExpiry option was set, the response will be cached using
// a hash of the metadata and request as the key.
func (c *cacheWrapper) Call(ctx context.Context, req client.Request, rsp interface{}, opts ...client.CallOption) error {
// parse the options
var options client.CallOptions
for _, o := range opts {
o(&options)
}
// if the client doesn't have a cacbe setup don't continue
cache := c.cacheFn()
if cache == nil {
return c.Client.Call(ctx, req, rsp, opts...)
}
// if the cache expiry is not set, execute the call without the cache
if options.CacheExpiry == 0 {
return c.Client.Call(ctx, req, rsp, opts...)
}
// if the response is nil don't call the cache since we can't assign the response
if rsp == nil {
return c.Client.Call(ctx, req, rsp, opts...)
}
// check to see if there is a response cached, if there is assign it
if r, ok := cache.Get(ctx, &req); ok {
val := reflect.ValueOf(rsp).Elem()
val.Set(reflect.ValueOf(r).Elem())
return nil
}
// don't cache the result if there was an error
if err := c.Client.Call(ctx, req, rsp, opts...); err != nil {
return err
}
// set the result in the cache
cache.Set(ctx, &req, rsp, options.CacheExpiry)
return nil
}
// CacheClient wraps requests with the cache wrapper
func CacheClient(cacheFn func() *client.Cache, c client.Client) client.Client {
return &cacheWrapper{cacheFn, c}
}
type staticClient struct {
address string
client.Client
}
func (s *staticClient) Call(ctx context.Context, req client.Request, rsp interface{}, opts ...client.CallOption) error {
return s.Client.Call(ctx, req, rsp, append(opts, client.WithAddress(s.address))...)
}
func (s *staticClient) Stream(ctx context.Context, req client.Request, opts ...client.CallOption) (client.Stream, error) {
return s.Client.Stream(ctx, req, append(opts, client.WithAddress(s.address))...)
}
// StaticClient sets an address on every call
func StaticClient(address string, c client.Client) client.Client {
return &staticClient{address, c}
}