core: initial commit for logger (#228)

* Replace "log.*" with logger.
* Add simple logger to log with log package.
* Add debug logs to all calls to these interfaces:
   - core.Application
   - core.Governance
   - core.Network
* Add Stringer to these types:
   - types.DKGComplaint
   - types.AgreementResult
   - types.DKGMasterPublicKey
   - types.DKGFinalize

3 files changed, 32 insertions, 1 deletions

diff --git a/core/types/block-randomness.go b/core/types/block-randomness.go
index b101e22..ebffd2b 100644
--- a/core/types/block-randomness.go
+++ b/core/types/block-randomness.go
@@ -18,6 +18,8 @@
 package types
 
 import (
+	"fmt"
+
 	"github.com/dexon-foundation/dexon-consensus-core/common"
 )
 
@@ -28,6 +30,11 @@ type AgreementResult struct {
 	Votes     []Vote      `json:"votes"`
 }
 
+func (r *AgreementResult) String() string {
+	return fmt.Sprintf(
+		"agreementResult[%s:%s]", r.BlockHash, &r.Position)
+}
+
 // BlockRandomnessResult describes a block randomness result
 type BlockRandomnessResult struct {
 	BlockHash  common.Hash `json:"block_hash"`
diff --git a/core/types/dkg.go b/core/types/dkg.go
index c13740b..6018ebd 100644
--- a/core/types/dkg.go
+++ b/core/types/dkg.go
@@ -53,6 +53,12 @@ type DKGMasterPublicKey struct {
 	Signature       crypto.Signature    `json:"signature"`
 }
 
+func (d *DKGMasterPublicKey) String() string {
+	return fmt.Sprintf("MasterPublicKey[%s:%d]",
+		d.ProposerID.String()[:6],
+		d.Round)
+}
+
 // NewDKGMasterPublicKey returns a new DKGMasterPublicKey instance.
 func NewDKGMasterPublicKey() *DKGMasterPublicKey {
 	return &DKGMasterPublicKey{
@@ -75,6 +81,11 @@ type DKGComplaint struct {
 	Signature    crypto.Signature `json:"signature"`
 }
 
+func (c *DKGComplaint) String() string {
+	return fmt.Sprintf("DKGComplaint[%s:%d]%s",
+		c.ProposerID.String()[:6], c.Round, &c.PrivateShare)
+}
+
 // DKGPartialSignature describe a partial signature in DKG protocol.
 type DKGPartialSignature struct {
 	ProposerID       NodeID               `json:"proposer_id"`
@@ -91,6 +102,12 @@ type DKGFinalize struct {
 	Signature  crypto.Signature `json:"signature"`
 }
 
+func (final *DKGFinalize) String() string {
+	return fmt.Sprintf("DKGFinal[%s:%d]",
+		final.ProposerID.String()[:6],
+		final.Round)
+}
+
 // IsNack returns true if it's a nack complaint in DKG protocol.
 func (c *DKGComplaint) IsNack() bool {
 	return len(c.PrivateShare.Signature.Signature) == 0
diff --git a/core/types/position.go b/core/types/position.go
index 4e254ba..51de405 100644
--- a/core/types/position.go
+++ b/core/types/position.go
@@ -17,7 +17,10 @@
 
 package types
 
-import "errors"
+import (
+	"errors"
+	"fmt"
+)
 
 // ErrComparePositionOnDifferentChains raised when attempting to
 // compare two positions with different chain ID.
@@ -31,6 +34,10 @@ type Position struct {
 	Height  uint64 `json:"height"`
 }
 
+func (pos *Position) String() string {
+	return fmt.Sprintf("pos[%d:%d:%d]", pos.ChainID, pos.Round, pos.Height)
+}
+
 // Equal checks if two positions are equal, it panics when their chainIDs
 // are different.
 func (pos *Position) Equal(other *Position) bool {