Close and retry a RemoteSigner on err (#2923)

* Close and recreate a RemoteSigner on err

* Update changelog

* Address Anton's comments / suggestions:

 - update changelog
 - restart TCPVal
 - shut down on `ErrUnexpectedResponse`

* re-init remote signer client with fresh connection if Ping fails

- add/update TODOs in secret connection
- rename tcp.go -> tcp_client.go, same with ipc to clarify their purpose

* account for `conn returned by waitConnection can be `nil`

- also add TODO about RemoteSigner conn field

* Tests for retrying: IPC / TCP

 - shorter info log on success
 - set conn and use it in tests to close conn

* Tests for retrying: IPC / TCP

 - shorter info log on success
 - set conn and use it in tests to close conn
 - add rwmutex for conn field in IPC

* comments and doc.go

* fix ipc tests. fixes #2677

* use constants for tests

* cleanup some error statements

* fixes #2784, race in tests

* remove print statement

* minor fixes from review

* update comment on sts spec

* cosmetics

* p2p/conn: add failing tests

* p2p/conn: make SecretConnection thread safe

* changelog

* IPCVal signer refactor

- use a .reset() method
- don't use embedded RemoteSignerClient
- guard RemoteSignerClient with mutex
- drop the .conn
- expose Close() on RemoteSignerClient

* apply IPCVal refactor to TCPVal

* remove mtx from RemoteSignerClient

* consolidate IPCVal and TCPVal, fixes #3104

- done in tcp_client.go
- now called SocketVal
- takes a listener in the constructor
- make tcpListener and unixListener contain all the differences

* delete ipc files

* introduce unix and tcp dialer for RemoteSigner

* rename files

- drop tcp_ prefix
- rename priv_validator.go to file.go

* bring back listener options

* fix node

* fix priv_val_server

* fix node test

* minor cleanup and comments

privval/old_file_test.go

@@ -0,0 +1,77 @@
+package privval_test
+
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/tendermint/tendermint/privval"
+)
+
+const oldPrivvalContent = `{
+  "address": "1D8089FAFDFAE4A637F3D616E17B92905FA2D91D",
+  "pub_key": {
+    "type": "tendermint/PubKeyEd25519",
+    "value": "r3Yg2AhDZ745CNTpavsGU+mRZ8WpRXqoJuyqjN8mJq0="
+  },
+  "last_height": "5",
+  "last_round": "0",
+  "last_step": 3,
+  "last_signature": "CTr7b9ZQlrJJf+12rPl5t/YSCUc/KqV7jQogCfFJA24e7hof69X6OMT7eFLVQHyodPjD/QTA298XHV5ejxInDQ==",
+  "last_signbytes": "750802110500000000000000220B08B398F3E00510F48DA6402A480A20FC258973076512999C3E6839A22E9FBDB1B77CF993E8A9955412A41A59D4CAD312240A20C971B286ACB8AAA6FCA0365EB0A660B189EDC08B46B5AF2995DEFA51A28D215B10013211746573742D636861696E2D533245415533",
+  "priv_key": {
+    "type": "tendermint/PrivKeyEd25519",
+    "value": "7MwvTGEWWjsYwjn2IpRb+GYsWi9nnFsw8jPLLY1UtP6vdiDYCENnvjkI1Olq+wZT6ZFnxalFeqgm7KqM3yYmrQ=="
+  }
+}`
+
+func TestLoadAndUpgrade(t *testing.T) {
+
+	oldFilePath := initTmpOldFile(t)
+	defer os.Remove(oldFilePath)
+	newStateFile, err := ioutil.TempFile("", "priv_validator_state*.json")
+	defer os.Remove(newStateFile.Name())
+	require.NoError(t, err)
+	newKeyFile, err := ioutil.TempFile("", "priv_validator_key*.json")
+	defer os.Remove(newKeyFile.Name())
+	require.NoError(t, err)
+
+	oldPV, err := privval.LoadOldFilePV(oldFilePath)
+	assert.NoError(t, err)
+	newPV := oldPV.Upgrade(newKeyFile.Name(), newStateFile.Name())
+
+	assertEqualPV(t, oldPV, newPV)
+	assert.NoError(t, err)
+	upgradedPV := privval.LoadFilePV(newKeyFile.Name(), newStateFile.Name())
+	assertEqualPV(t, oldPV, upgradedPV)
+	oldPV, err = privval.LoadOldFilePV(oldFilePath + ".bak")
+	require.NoError(t, err)
+	assertEqualPV(t, oldPV, upgradedPV)
+}
+
+func assertEqualPV(t *testing.T, oldPV *privval.OldFilePV, newPV *privval.FilePV) {
+	assert.Equal(t, oldPV.Address, newPV.Key.Address)
+	assert.Equal(t, oldPV.Address, newPV.GetAddress())
+	assert.Equal(t, oldPV.PubKey, newPV.Key.PubKey)
+	assert.Equal(t, oldPV.PubKey, newPV.GetPubKey())
+	assert.Equal(t, oldPV.PrivKey, newPV.Key.PrivKey)
+
+	assert.Equal(t, oldPV.LastHeight, newPV.LastSignState.Height)
+	assert.Equal(t, oldPV.LastRound, newPV.LastSignState.Round)
+	assert.Equal(t, oldPV.LastSignature, newPV.LastSignState.Signature)
+	assert.Equal(t, oldPV.LastSignBytes, newPV.LastSignState.SignBytes)
+	assert.Equal(t, oldPV.LastStep, newPV.LastSignState.Step)
+}
+
+func initTmpOldFile(t *testing.T) string {
+	tmpfile, err := ioutil.TempFile("", "priv_validator_*.json")
+	require.NoError(t, err)
+	t.Logf("created test file %s", tmpfile.Name())
+	_, err = tmpfile.WriteString(oldPrivvalContent)
+	require.NoError(t, err)
+
+	return tmpfile.Name()
+}