go/governance: Implement PrettyPrint interface for various types

Implement PrettyPrint for ProposalContent, UpgradeProposal,
CancelUpgradeProposal and ProposalVote types.

.changelog/3800.feature.2.md

@@ -0,0 +1,4 @@
+go/governance: Implement `PrettyPrint` interface for various types
+
+Implement `PrettyPrinter` for `ProposalContent`, `UpgradeProposal`,
+`CancelUpgradeProposal` and `ProposalVote` types.

go/governance/api/api.go

@@ -4,10 +4,12 @@ package api
 import (
 	"context"
 	"fmt"
+	"io"
 
 	beacon "github.com/oasisprotocol/oasis-core/go/beacon/api"
 	"github.com/oasisprotocol/oasis-core/go/common/crypto/hash"
 	"github.com/oasisprotocol/oasis-core/go/common/errors"
+	"github.com/oasisprotocol/oasis-core/go/common/prettyprint"
 	"github.com/oasisprotocol/oasis-core/go/common/pubsub"
 	"github.com/oasisprotocol/oasis-core/go/common/quantity"
 	"github.com/oasisprotocol/oasis-core/go/consensus/api/transaction"
@@ -18,6 +20,10 @@ import (
 // ModuleName is a unique module name for the governance backend.
 const ModuleName = "governance"
 
+// ProposalContentInvalidText is the textual representation of an invalid
+// ProposalContent.
+const ProposalContentInvalidText = "(invalid)"
+
 var (
 	// ErrInvalidArgument is the error returned on malformed argument(s).
 	ErrInvalidArgument = errors.New(ModuleName, 1, "governance: invalid argument")
@@ -44,6 +50,11 @@ var (
 		MethodSubmitProposal,
 		MethodCastVote,
 	}
+
+	_ prettyprint.PrettyPrinter = (*ProposalContent)(nil)
+	_ prettyprint.PrettyPrinter = (*UpgradeProposal)(nil)
+	_ prettyprint.PrettyPrinter = (*CancelUpgradeProposal)(nil)
+	_ prettyprint.PrettyPrinter = (*ProposalVote)(nil)
 )
 
 // ProposalContent is a consensus layer governance proposal content.
@@ -82,17 +93,62 @@ func (p *ProposalContent) Equals(other *ProposalContent) bool {
 	}
 }
 
+// PrettyPrint writes a pretty-printed representation of ProposalContent to the
+// given writer.
+func (p ProposalContent) PrettyPrint(ctx context.Context, prefix string, w io.Writer) {
+	switch {
+	case p.Upgrade != nil && p.CancelUpgrade == nil:
+		fmt.Fprintf(w, "%sUpgrade:\n", prefix)
+		p.Upgrade.PrettyPrint(ctx, prefix+"  ", w)
+	case p.CancelUpgrade != nil && p.Upgrade == nil:
+		fmt.Fprintf(w, "%sCancel Upgrade:\n", prefix)
+		p.CancelUpgrade.PrettyPrint(ctx, prefix+"  ", w)
+	default:
+		fmt.Fprintf(w, "%s%s\n", prefix, ProposalContentInvalidText)
+	}
+}
+
+// PrettyType returns a representation of ProposalContent that can be used for
+// pretty printing.
+func (p ProposalContent) PrettyType() (interface{}, error) {
+	return p, nil
+}
+
 // UpgradeProposal is an upgrade proposal.
 type UpgradeProposal struct {
 	upgrade.Descriptor
 }
 
+// PrettyPrint writes a pretty-printed representation of UpgradeProposal to the
+// given writer.
+func (u UpgradeProposal) PrettyPrint(ctx context.Context, prefix string, w io.Writer) {
+	u.Descriptor.PrettyPrint(ctx, prefix, w)
+}
+
+// PrettyType returns a representation of UpgradeProposal that can be used for
+// pretty printing.
+func (u UpgradeProposal) PrettyType() (interface{}, error) {
+	return u, nil
+}
+
 // CancelUpgradeProposal is an upgrade cancellation proposal.
 type CancelUpgradeProposal struct {
 	// ProposalID is the identifier of the pending upgrade proposal.
 	ProposalID uint64 `json:"proposal_id"`
 }
 
+// PrettyPrint writes a pretty-printed representation of CancelUpgradeProposal
+// to the given writer.
+func (cu CancelUpgradeProposal) PrettyPrint(ctx context.Context, prefix string, w io.Writer) {
+	fmt.Fprintf(w, "%sProposal ID: %d\n", prefix, cu.ProposalID)
+}
+
+// PrettyType returns a representation of CancelUpgradeProposal that can be used
+// for pretty printing.
+func (cu CancelUpgradeProposal) PrettyType() (interface{}, error) {
+	return cu, nil
+}
+
 // ProposalVote is a vote for a proposal.
 type ProposalVote struct {
 	// ID is the unique identifier of a proposal.
@@ -101,6 +157,19 @@ type ProposalVote struct {
 	Vote Vote `json:"vote"`
 }
 
+// PrettyPrint writes a pretty-printed representation of ProposalVote to the
+// given writer.
+func (pv ProposalVote) PrettyPrint(ctx context.Context, prefix string, w io.Writer) {
+	fmt.Fprintf(w, "%sProposal ID: %d\n", prefix, pv.ID)
+	fmt.Fprintf(w, "%sVote:        %s\n", prefix, pv.Vote)
+}
+
+// PrettyType returns a representation of ProposalVote that can be used for
+// pretty printing.
+func (pv ProposalVote) PrettyType() (interface{}, error) {
+	return pv, nil
+}
+
 // Backend is a governance implementation.
 type Backend interface {
 	// ActiveProposals returns a list of all proposals that have not yet closed.

go/governance/api/api_test.go

@@ -1,6 +1,8 @@
 package api
 
 import (
+	"bytes"
+	"context"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -139,3 +141,44 @@ func TestProposalContentEquals(t *testing.T) {
 		require.Equal(t, tc.equals, tc.p1.Equals(tc.p2), tc.msg)
 	}
 }
+
+func TestProposalContentPrettyPrint(t *testing.T) {
+	for _, tc := range []struct {
+		expRegex string
+		p        *ProposalContent
+	}{
+		{
+			expRegex: "^Upgrade:",
+			p: &ProposalContent{
+				Upgrade: &UpgradeProposal{
+					Descriptor: api.Descriptor{Handler: "test"},
+				},
+			},
+		},
+		{
+			expRegex: "^Cancel Upgrade:",
+			p: &ProposalContent{
+				CancelUpgrade: &CancelUpgradeProposal{ProposalID: 42},
+			},
+		},
+		{
+			expRegex: ProposalContentInvalidText,
+			p:        &ProposalContent{},
+		},
+		{
+			expRegex: ProposalContentInvalidText,
+			p: &ProposalContent{
+				Upgrade: &UpgradeProposal{
+					Descriptor: api.Descriptor{Handler: "test"},
+				},
+				CancelUpgrade: &CancelUpgradeProposal{ProposalID: 42},
+			},
+		},
+	} {
+		var actualPrettyPrint bytes.Buffer
+		tc.p.PrettyPrint(context.Background(), "", &actualPrettyPrint)
+		require.Regexp(t, tc.expRegex, actualPrettyPrint.String(),
+			"pretty printing proposal content didn't return the expected result",
+		)
+	}
+}