fixed immediate timeout

* fixes #126

This PR implements the proposal N°1 exposed in issue #126:
* if there is a non-zero timeout set with the request, we
  add this timeout to the operation context
* applicable contexts are:
   runtime.Context -> operation.Context -> context.WithTimeout(t>0)
* the actual behavior is determined by the shortest deadline set on those
  contexts

* added unit tests to assert that the different contexts are formed
correctly:
  * an operation with no context inherits from the runtime context
  * an operation with no timeout set (by context or parameter) defaults to 30s (default timeout)
  * when several timeouts are set, the shortest wins
  * an operation with no timeout in context and a 0 timeout param waits
for ever (and not with immediate timeout)

Signed-off-by: Frédéric BIDON <[email protected]>

client/runtime.go

@@ -457,27 +457,36 @@ func (r *Runtime) Submit(operation *runtime.ClientOperation) (interface{}, error
  r.logger.Debugf("%s\n", string(b))
  }
 
- var hasTimeout bool
- pctx := operation.Context
- if pctx == nil {
- pctx = r.Context
- } else {
- hasTimeout = true
- }
- if pctx == nil {
- pctx = context.Background()
+ var parentCtx context.Context
+ switch {
+ case operation.Context != nil:
+ parentCtx = operation.Context
+ case r.Context != nil:
+ parentCtx = r.Context
+ default:
+ parentCtx = context.Background()
  }
- var ctx context.Context
- var cancel context.CancelFunc
- if hasTimeout {
- ctx, cancel = context.WithCancel(pctx)
+
+ var (
+ ctx context.Context
+ cancel context.CancelFunc
+ )
+ if request.timeout == 0 {
+ // There may be a deadline in the context passed to the operation.
+ // Otherwise, there is no timeout set.
+ ctx, cancel = context.WithCancel(parentCtx)
  } else {
- ctx, cancel = context.WithTimeout(pctx, request.timeout)
+ // Sets the timeout passed from request params (by default runtime.DefaultTimeout).
+ // If there is already a deadline in the parent context, the shortest will
+ // apply.
+ ctx, cancel = context.WithTimeout(parentCtx, request.timeout)
  }
  defer cancel()
 
- client := operation.Client
- if client == nil {
+ var client *http.Client
+ if operation.Client != nil {
+ client = operation.Client
+ } else {
  client = r.client
  }
  req = req.WithContext(ctx)