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Recover from panic in cosmos store #1257

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merged 2 commits into from
Aug 24, 2019
Merged

Recover from panic in cosmos store #1257

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3dfd9bd
Recover from panic in cosmos store
krhubert Aug 23, 2019
c563310
Merge branch 'dev' into feature/cosmos-store
antho1404 Aug 24, 2019
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75 changes: 63 additions & 12 deletions database/store/cosmos.go
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@ package store

import (
"errors"
"fmt"

"github.com/cosmos/cosmos-sdk/types"
)
Expand All @@ -24,32 +25,67 @@ func (s *CosmosStore) NewIterator() Iterator {
}

// Has returns true if the key is set in the store.
func (s *CosmosStore) Has(key []byte) (bool, error) {
return s.store.Has(key), nil
func (s *CosmosStore) Has(key []byte) (has bool, err error) {
defer func() {
if r := recover(); r != nil {
var ok bool
if err, ok = r.(error); !ok {
err = fmt.Errorf("store: %s", r)
}
}
}()
has = s.store.Has(key)
return
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can we return explicitly the error here and avoid to have named outputs to be consistent with the rest of the codebase

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Unfortunately, that's not possible with the error recover system. The output have to be named in order to be "replaced" by the defer function.

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declaring an error variable at the beginning of the function wouldn't work?

func (s *CosmosStore) Has(key []byte) (bool, error) {
	var err error
	defer func() {
		if r := recover(); r != nil {
			var ok bool
			if err, ok = r.(error); !ok {
				err = fmt.Errorf("store: %s", r)
			}
		}
	}()
	return s.store.Has(key), err
}

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Nope, because defer is invoked
"after" retrun statment, not before :/

you can read about this in details here https://medium.com/@blanchon.vincent/go-how-does-defer-statement-work-1a9492689b6e

}

// Get retrives service from store. It returns an error if the store does not contains the key.
func (s *CosmosStore) Get(key []byte) ([]byte, error) {
func (s *CosmosStore) Get(key []byte) (out []byte, err error) {
defer func() {
if r := recover(); r != nil {
var ok bool
if err, ok = r.(error); !ok {
err = fmt.Errorf("store: %s", r)
}
}
}()

has, err := s.Has(key)
if err != nil {
return nil, err
}
if !has {
return nil, errors.New("not found")
}
return s.store.Get(key), nil
out = s.store.Get(key)
return
}

// Delete deletes the value for the given key. Delete will not returns error if key doesn't exist.
func (s *CosmosStore) Delete(key []byte) error {
func (s *CosmosStore) Delete(key []byte) (err error) {
defer func() {
if r := recover(); r != nil {
var ok bool
if err, ok = r.(error); !ok {
err = fmt.Errorf("store: %s", r)
}
}
}()
s.store.Delete(key)
return nil
return
}

// Put sets the value for the given key. It overwrites any previous value.
func (s *CosmosStore) Put(key []byte, value []byte) error {
func (s *CosmosStore) Put(key []byte, value []byte) (err error) {
defer func() {
if r := recover(); r != nil {
var ok bool
if err, ok = r.(error); !ok {
err = fmt.Errorf("store: %s", r)
}
}
}()
s.store.Set(key, value)
return nil
return
}

// Close closes the store.
Expand All @@ -60,6 +96,7 @@ func (s *CosmosStore) Close() error {
// CosmosIterator is a Cosmos KVStore's iterator implementation of Iterator.
type CosmosIterator struct {
iter types.Iterator
err error
}

// NewCosmosIterator returns a new Cosmos KVStore Iterator wrapper.
Expand All @@ -71,29 +108,43 @@ func NewCosmosIterator(iter types.Iterator) *CosmosIterator {

// Next moves the iterator to the next sequential key in the store.
func (i *CosmosIterator) Next() bool {
if i.iter.Valid() {
defer i.handleError()
valid := i.iter.Valid()
if valid {
i.iter.Next()
return true
}
return false
return valid
}

// Key returns the key of the cursor.
func (i *CosmosIterator) Key() []byte {
defer i.handleError()
return i.iter.Key()
}

// Value returns the value of the cursor.
func (i *CosmosIterator) Value() []byte {
defer i.handleError()
return i.iter.Value()
}

// Release releases the Iterator.
func (i *CosmosIterator) Release() {
defer i.handleError()
i.iter.Close()
}

// Error returns any accumulated error.
func (i *CosmosIterator) Error() error {
return nil
return i.err
}

// returns any accumulated error.
func (i *CosmosIterator) handleError() {
if r := recover(); r != nil {
var ok bool
if i.err, ok = r.(error); !ok {
i.err = fmt.Errorf("store iterator: %s", r)
}
}
}