Copy certifiers from light-client

certifiers/client/main_test.go

@@ -0,0 +1,25 @@
+package client_test
+
+import (
+	"os"
+	"testing"
+
+	"github.com/tendermint/abci/example/dummy"
+
+	nm "github.com/tendermint/tendermint/node"
+	rpctest "github.com/tendermint/tendermint/rpc/test"
+)
+
+var node *nm.Node
+
+func TestMain(m *testing.M) {
+	// start a tendermint node (and merkleeyes) in the background to test against
+	app := dummy.NewDummyApplication()
+	node = rpctest.StartTendermint(app)
+	code := m.Run()
+
+	// and shut down proper at the end
+	node.Stop()
+	node.Wait()
+	os.Exit(code)
+}

certifiers/client/provider.go

@@ -0,0 +1,129 @@
+/*
+Package client defines a provider that uses a rpcclient
+to get information, which is used to get new headers
+and validators directly from a node.
+*/
+package client
+
+import (
+	"bytes"
+
+	rpcclient "github.com/tendermint/tendermint/rpc/client"
+	ctypes "github.com/tendermint/tendermint/rpc/core/types"
+	"github.com/tendermint/tendermint/types"
+
+	"github.com/tendermint/tendermint/certifiers"
+	certerr "github.com/tendermint/tendermint/certifiers/errors"
+)
+
+type SignStatusClient interface {
+	rpcclient.SignClient
+	rpcclient.StatusClient
+}
+
+type provider struct {
+	node       SignStatusClient
+	lastHeight int
+}
+
+// NewProvider can wrap any rpcclient to expose it as
+// a read-only provider.
+func NewProvider(node SignStatusClient) certifiers.Provider {
+	return &provider{node: node}
+}
+
+// NewProvider can connects to a tendermint json-rpc endpoint
+// at the given url, and uses that as a read-only provider.
+func NewHTTPProvider(remote string) certifiers.Provider {
+	return &provider{
+		node: rpcclient.NewHTTP(remote, "/websocket"),
+	}
+}
+
+// StoreCommit is a noop, as clients can only read from the chain...
+func (p *provider) StoreCommit(_ certifiers.FullCommit) error { return nil }
+
+// GetHash gets the most recent validator and sees if it matches
+//
+// TODO: improve when the rpc interface supports more functionality
+func (p *provider) GetByHash(hash []byte) (certifiers.FullCommit, error) {
+	var fc certifiers.FullCommit
+	vals, err := p.node.Validators(nil)
+	// if we get no validators, or a different height, return an error
+	if err != nil {
+		return fc, err
+	}
+	p.updateHeight(vals.BlockHeight)
+	vhash := types.NewValidatorSet(vals.Validators).Hash()
+	if !bytes.Equal(hash, vhash) {
+		return fc, certerr.ErrCommitNotFound()
+	}
+	return p.seedFromVals(vals)
+}
+
+// GetByHeight gets the validator set by height
+func (p *provider) GetByHeight(h int) (fc certifiers.FullCommit, err error) {
+	commit, err := p.node.Commit(&h)
+	if err != nil {
+		return fc, err
+	}
+	return p.seedFromCommit(commit)
+}
+
+func (p *provider) LatestCommit() (fc certifiers.FullCommit, err error) {
+	commit, err := p.GetLatestCommit()
+	if err != nil {
+		return fc, err
+	}
+	return p.seedFromCommit(commit)
+}
+
+// GetLatestCommit should return the most recent commit there is,
+// which handles queries for future heights as per the semantics
+// of GetByHeight.
+func (p *provider) GetLatestCommit() (*ctypes.ResultCommit, error) {
+	status, err := p.node.Status()
+	if err != nil {
+		return nil, err
+	}
+	return p.node.Commit(&status.LatestBlockHeight)
+}
+
+func (p *provider) seedFromVals(vals *ctypes.ResultValidators) (certifiers.FullCommit, error) {
+	// now get the commits and build a full commit
+	commit, err := p.node.Commit(&vals.BlockHeight)
+	if err != nil {
+		return certifiers.FullCommit{}, err
+	}
+	fc := certifiers.NewFullCommit(
+		certifiers.CommitFromResult(commit),
+		types.NewValidatorSet(vals.Validators),
+	)
+	return fc, nil
+}
+
+func (p *provider) seedFromCommit(commit *ctypes.ResultCommit) (fc certifiers.FullCommit, err error) {
+	fc.Commit = certifiers.CommitFromResult(commit)
+
+	// now get the proper validators
+	vals, err := p.node.Validators(&commit.Header.Height)
+	if err != nil {
+		return fc, err
+	}
+
+	// make sure they match the commit (as we cannot enforce height)
+	vset := types.NewValidatorSet(vals.Validators)
+	if !bytes.Equal(vset.Hash(), commit.Header.ValidatorsHash) {
+		return fc, certerr.ErrValidatorsChanged()
+	}
+
+	p.updateHeight(commit.Header.Height)
+	fc.Validators = vset
+	return fc, nil
+}
+
+func (p *provider) updateHeight(h int) {
+	if h > p.lastHeight {
+		p.lastHeight = h
+	}
+}

certifiers/client/provider_test.go

@@ -0,0 +1,62 @@
+package client_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	rpctest "github.com/tendermint/tendermint/rpc/test"
+
+	"github.com/tendermint/tendermint/certifiers"
+	"github.com/tendermint/tendermint/certifiers/client"
+	certerr "github.com/tendermint/tendermint/certifiers/errors"
+)
+
+func TestProvider(t *testing.T) {
+	assert, require := assert.New(t), require.New(t)
+
+	cfg := rpctest.GetConfig()
+	rpcAddr := cfg.RPC.ListenAddress
+	chainID := cfg.ChainID
+	p := client.NewHTTPProvider(rpcAddr)
+	require.NotNil(t, p)
+
+	// let it produce some blocks
+	time.Sleep(500 * time.Millisecond)
+
+	// let's get the highest block
+	seed, err := p.LatestCommit()
+
+	require.Nil(err, "%+v", err)
+	sh := seed.Height()
+	vhash := seed.Header.ValidatorsHash
+	assert.True(sh < 5000)
+
+	// let's check this is valid somehow
+	assert.Nil(seed.ValidateBasic(chainID))
+	cert := certifiers.NewStatic(chainID, seed.Validators)
+
+	// historical queries now work :)
+	lower := sh - 5
+	seed, err = p.GetByHeight(lower)
+	assert.Nil(err, "%+v", err)
+	assert.Equal(lower, seed.Height())
+
+	// also get by hash (given the match)
+	seed, err = p.GetByHash(vhash)
+	require.Nil(err, "%+v", err)
+	require.Equal(vhash, seed.Header.ValidatorsHash)
+	err = cert.Certify(seed.Commit)
+	assert.Nil(err, "%+v", err)
+
+	// get by hash fails without match
+	seed, err = p.GetByHash([]byte("foobar"))
+	assert.NotNil(err)
+	assert.True(certerr.IsCommitNotFoundErr(err))
+
+	// storing the seed silently ignored
+	err = p.StoreCommit(seed)
+	assert.Nil(err, "%+v", err)
+}