Add errlint

.golangci.yml

@@ -9,6 +9,7 @@ linters:
     - copyloopvar
     - dupl
     - errcheck
+    - errorlint
     - funlen
     - gocritic
     - govet
@@ -25,6 +26,10 @@ linters:
   settings:
     dupl:
       threshold: 400
+    errorlint:
+      errorf: true
+      asserts: true
+      comparison: true
     funlen:
       lines: 400
       statements: 200

internal/app/active_nodes.go

@@ -1,6 +1,7 @@
 package app
 
 import (
+	"errors"
 	"fmt"
 	"slices"
 	"sort"
@@ -15,7 +16,7 @@ func (app *App) GetActiveNodes() ([]string, error) {
 	var activeNodes []string
 	err := app.dcs.Get(pathActiveNodes, &activeNodes)
 	if err != nil {
-		if err == dcs.ErrNotFound {
+		if errors.Is(err, dcs.ErrNotFound) {
 			return nil, nil
 		}
 		return nil, fmt.Errorf("get active nodes from dcs: %s", err.Error())

internal/app/candidate.go

@@ -1,6 +1,8 @@
 package app
 
 import (
+	"errors"
+
 	"github.com/yandex/rdsync/internal/dcs"
 )
 
@@ -20,7 +22,7 @@ func (app *App) stateCandidate() appState {
 		app.logger.Info().Msgf("Shard state: %v", shardState)
 	}
 	maintenance, err := app.GetMaintenance()
-	if err != nil && err != dcs.ErrNotFound {
+	if err != nil && !errors.Is(err, dcs.ErrNotFound) {
 		app.logger.Error().Err(err).Msg("Candidate: failed to get maintenance from DCS")
 		return stateCandidate
 	}
@@ -29,7 +31,7 @@ func (app *App) stateCandidate() appState {
 	}
 
 	poisonPill, err := app.getPoisonPill()
-	if err != nil && err != dcs.ErrNotFound {
+	if err != nil && !errors.Is(err, dcs.ErrNotFound) {
 		app.logger.Error().Err(err).Msg("Candidate: failed to get poison pill from DCS")
 		return stateCandidate
 	}
@@ -46,7 +48,7 @@ func (app *App) stateCandidate() appState {
 
 	var master string
 	err = app.dcs.Get(pathMasterNode, &master)
-	if err != nil && err != dcs.ErrNotFound {
+	if err != nil && !errors.Is(err, dcs.ErrNotFound) {
 		app.logger.Error().Err(err).Msg("Candidate: failed to get current master from DCS")
 		return stateCandidate
 	}

internal/app/cli.go

@@ -3,6 +3,7 @@ package app
 import (
 	"bufio"
 	"context"
+	"errors"
 	"fmt"
 
 	"os"
@@ -69,7 +70,7 @@ func (app *App) CliInfo(verbose bool) int {
 			err = app.dcs.Get(path, &switchover)
 			if err == nil {
 				data[path] = switchover.String()
-			} else if err != dcs.ErrNotFound {
+			} else if !errors.Is(err, dcs.ErrNotFound) {
 				app.logger.Error().Err(err).Msgf("Failed to get %s", path)
 				return 1
 			}
@@ -79,7 +80,7 @@ func (app *App) CliInfo(verbose bool) int {
 		err = app.dcs.Get(pathMaintenance, &maintenance)
 		if err == nil {
 			data[pathMaintenance] = maintenance.String()
-		} else if err != dcs.ErrNotFound {
+		} else if !errors.Is(err, dcs.ErrNotFound) {
 			app.logger.Error().Err(err).Msgf("Failed to get %s", pathMaintenance)
 			return 1
 		}
@@ -88,22 +89,22 @@ func (app *App) CliInfo(verbose bool) int {
 		err = app.dcs.Get(pathPoisonPill, &poisonPill)
 		if err == nil {
 			data[pathPoisonPill] = poisonPill.String()
-		} else if err != dcs.ErrNotFound {
+		} else if !errors.Is(err, dcs.ErrNotFound) {
 			app.logger.Error().Err(err).Msgf("Failed to get %s", pathPoisonPill)
 			return 1
 		}
 
 		var manager dcs.LockOwner
 		err = app.dcs.Get(pathManagerLock, &manager)
-		if err != nil && err != dcs.ErrNotFound {
+		if err != nil && !errors.Is(err, dcs.ErrNotFound) {
 			app.logger.Error().Err(err).Msgf("Failed to get %s", pathManagerLock)
 			return 1
 		}
 		data[pathManagerLock] = manager.Hostname
 
 		var master string
 		err = app.dcs.Get(pathMasterNode, &master)
-		if err != nil && err != dcs.ErrNotFound {
+		if err != nil && !errors.Is(err, dcs.ErrNotFound) {
 			app.logger.Error().Err(err).Msgf("Failed to get %s", pathMasterNode)
 			return 1
 		}
@@ -287,7 +288,7 @@ func (app *App) CliSwitch(switchFrom, switchTo string, waitTimeout time.Duration
 		app.logger.Error().Msgf("Another switchover in progress %v", switchover)
 		return 2
 	}
-	if err != dcs.ErrNotFound {
+	if !errors.Is(err, dcs.ErrNotFound) {
 		app.logger.Error().Err(err).Msg("Unable to get current switchover status")
 		return 2
 	}
@@ -307,7 +308,7 @@ func (app *App) CliSwitch(switchFrom, switchTo string, waitTimeout time.Duration
 	}
 
 	err = app.dcs.Create(pathCurrentSwitch, switchover)
-	if err == dcs.ErrExists {
+	if errors.Is(err, dcs.ErrExists) {
 		app.logger.Error().Msg("Another switchover in progress")
 		return 2
 	}
@@ -364,7 +365,7 @@ func (app *App) CliEnableMaintenance(waitTimeout time.Duration) int {
 		InitiatedAt: time.Now(),
 	}
 	err = app.dcs.Create(pathMaintenance, maintenance)
-	if err != nil && err != dcs.ErrExists {
+	if err != nil && !errors.Is(err, dcs.ErrExists) {
 		app.logger.Error().Err(err).Msg("Unable to create maintenance path in dcs")
 		return 1
 	}
@@ -410,7 +411,7 @@ func (app *App) CliDisableMaintenance(waitTimeout time.Duration) int {
 
 	maintenance := &Maintenance{}
 	err = app.dcs.Get(pathMaintenance, maintenance)
-	if err == dcs.ErrNotFound {
+	if errors.Is(err, dcs.ErrNotFound) {
 		fmt.Println("maintenance disabled")
 		return 0
 	} else if err != nil {
@@ -432,7 +433,7 @@ func (app *App) CliDisableMaintenance(waitTimeout time.Duration) int {
 			select {
 			case <-ticker.C:
 				err = app.dcs.Get(pathMaintenance, maintenance)
-				if err == dcs.ErrNotFound {
+				if errors.Is(err, dcs.ErrNotFound) {
 					maintenance = nil
 					break Out
 				}
@@ -466,15 +467,15 @@ func (app *App) CliGetMaintenance() int {
 
 	var maintenance Maintenance
 	err = app.dcs.Get(pathMaintenance, &maintenance)
-	switch err {
-	case nil:
+	switch {
+	case err == nil:
 		if maintenance.RdSyncPaused {
 			fmt.Println("on")
 		} else {
 			fmt.Println("scheduled")
 		}
 		return 0
-	case dcs.ErrNotFound:
+	case errors.Is(err, dcs.ErrNotFound):
 		fmt.Println("off")
 		return 0
 	default:
@@ -494,7 +495,7 @@ func (app *App) CliAbort() int {
 	app.dcs.Initialize()
 
 	err = app.dcs.Get(pathCurrentSwitch, new(Switchover))
-	if err == dcs.ErrNotFound {
+	if errors.Is(err, dcs.ErrNotFound) {
 		fmt.Println("no active switchover")
 		return 0
 	}
@@ -578,7 +579,7 @@ func (app *App) CliHostAdd(host string, priority *int, dryRun bool, skipValkeyCh
 
 	// root path probably does not exist
 	err = app.dcs.Create(dcs.JoinPath(pathHANodes), nil)
-	if err != nil && err != dcs.ErrExists {
+	if err != nil && !errors.Is(err, dcs.ErrExists) {
 		return 1
 	}
 
@@ -598,7 +599,7 @@ func (app *App) CliHostAdd(host string, priority *int, dryRun bool, skipValkeyCh
 
 	if !dryRun && priority == nil {
 		err = app.dcs.Set(dcs.JoinPath(pathHANodes, host), *valkey.DefaultNodeConfiguration())
-		if err != nil && err != dcs.ErrExists {
+		if err != nil && !errors.Is(err, dcs.ErrExists) {
 			app.logger.Error().Err(err).Msgf("Unable to create dcs path for %s", host)
 			return 1
 		}
@@ -632,7 +633,7 @@ func (app *App) CliHostRemove(host string) int {
 	app.dcs.Initialize()
 
 	err = app.dcs.Delete(dcs.JoinPath(pathHANodes, host))
-	if err != nil && err != dcs.ErrNotFound {
+	if err != nil && !errors.Is(err, dcs.ErrNotFound) {
 		app.logger.Error().Err(err).Msgf("Unable to delete dcs path for %s", host)
 		return 1
 	}
@@ -668,7 +669,7 @@ func (app *App) processPriority(priority *int, dryRun bool, host string) (change
 	}
 
 	err = app.dcs.Set(dcs.JoinPath(pathHANodes, host), targetConf)
-	if err != nil && err != dcs.ErrExists {
+	if err != nil && !errors.Is(err, dcs.ErrExists) {
 		return false, err
 	}
 

internal/app/failover.go

@@ -1,6 +1,7 @@
 package app
 
 import (
+	"errors"
 	"fmt"
 	"time"
 
@@ -56,7 +57,7 @@ func (app *App) approveFailover(shardState map[string]*HostState, activeNodes []
 
 	var lastSwitchover Switchover
 	err := app.dcs.Get(pathLastSwitch, &lastSwitchover)
-	if err != dcs.ErrNotFound {
+	if !errors.Is(err, dcs.ErrNotFound) {
 		if err != nil {
 			return err
 		}

internal/app/maintenance.go

@@ -1,6 +1,7 @@
 package app
 
 import (
+	"errors"
 	"fmt"
 	"os"
 
@@ -94,10 +95,10 @@ func (app *App) stateMaintenance() appState {
 		app.createMaintenanceFile()
 	}
 	maintenance, err := app.GetMaintenance()
-	if err != nil && err != dcs.ErrNotFound {
+	if err != nil && !errors.Is(err, dcs.ErrNotFound) {
 		return stateMaintenance
 	}
-	if err == dcs.ErrNotFound || maintenance.ShouldLeave {
+	if errors.Is(err, dcs.ErrNotFound) || maintenance.ShouldLeave {
 		if app.dcs.AcquireLock(pathManagerLock) {
 			app.logger.Info().Msg("Leaving maintenance")
 			err := app.leaveMaintenance()

internal/app/manager.go

@@ -2,6 +2,7 @@ package app
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"time"
 
@@ -50,7 +51,7 @@ func (app *App) stateManager() appState {
 	app.logger.Info().Msgf("DCS shard state: %v", shardStateDcs)
 
 	maintenance, err := app.GetMaintenance()
-	if err != nil && err != dcs.ErrNotFound {
+	if err != nil && !errors.Is(err, dcs.ErrNotFound) {
 		app.logger.Error().Err(err).Msg("Failed to get maintenance from dcs")
 		return stateManager
 	}
@@ -94,7 +95,7 @@ func (app *App) stateManager() appState {
 			return stateManager
 		}
 		err = app.performSwitchover(shardState, activeNodes, &switchover, master)
-		if app.dcs.Get(pathCurrentSwitch, new(Switchover)) == dcs.ErrNotFound {
+		if errors.Is(app.dcs.Get(pathCurrentSwitch, new(Switchover)), dcs.ErrNotFound) {
 			app.logger.Error().Msg("Switchover was aborted")
 		} else {
 			if err != nil {
@@ -110,12 +111,12 @@ func (app *App) stateManager() appState {
 			}
 		}
 		return stateManager
-	} else if err != dcs.ErrNotFound {
+	} else if !errors.Is(err, dcs.ErrNotFound) {
 		app.logger.Error().Err(err).Msg("Getting current switchover failed")
 		return stateManager
 	}
 	poisonPill, err := app.getPoisonPill()
-	if err != nil && err != dcs.ErrNotFound {
+	if err != nil && !errors.Is(err, dcs.ErrNotFound) {
 		app.logger.Error().Err(err).Msg("Manager: failed to get poison pill from DCS")
 		return stateManager
 	}

internal/app/master.go

@@ -1,6 +1,7 @@
 package app
 
 import (
+	"errors"
 	"fmt"
 	"time"
 
@@ -14,8 +15,8 @@ func (app *App) getNumReplicasToWrite(activeNodes []string) int {
 func (app *App) getCurrentMaster(shardState map[string]*HostState) (string, error) {
 	var master string
 	err := app.dcs.Get(pathMasterNode, &master)
-	if err != nil && err != dcs.ErrNotFound {
-		return "", fmt.Errorf("failed to get current master from dcs: %s", err)
+	if err != nil && !errors.Is(err, dcs.ErrNotFound) {
+		return "", fmt.Errorf("failed to get current master from dcs: %w", err)
 	}
 	if master != "" {
 		stateMaster, err := app.getMasterHost(shardState)
@@ -84,7 +85,7 @@ func (app *App) ensureCurrentMaster(shardState map[string]*HostState) (string, e
 	}
 	err = app.dcs.Set(pathMasterNode, master)
 	if err != nil {
-		return "", fmt.Errorf("failed to set current master in dcs: %s", err)
+		return "", fmt.Errorf("failed to set current master in dcs: %w", err)
 	}
 	return master, nil
 }

internal/app/replication.go

@@ -1,6 +1,7 @@
 package app
 
 import (
+	"errors"
 	"fmt"
 	"slices"
 	"time"
@@ -80,7 +81,7 @@ func (app *App) closeStaleReplica(master string) error {
 			app.logger.Debug().Msgf("Skipping staleness close due to switchover in progress: %v.", switchover)
 			return nil
 		}
-		if err != dcs.ErrNotFound {
+		if !errors.Is(err, dcs.ErrNotFound) {
 			return err
 		}
 		shardState, err := app.getShardStateFromDcs()

internal/app/state.go

@@ -1,6 +1,7 @@
 package app
 
 import (
+	"errors"
 	"fmt"
 	"strconv"
 	"strings"
@@ -201,7 +202,7 @@ func (app *App) getShardStateFromDcs() (map[string]*HostState, error) {
 	getter := func(host string) (*HostState, error) {
 		var state HostState
 		err := app.dcs.Get(dcs.JoinPath(pathHealthPrefix, host), &state)
-		if err != nil && err != dcs.ErrNotFound {
+		if err != nil && !errors.Is(err, dcs.ErrNotFound) {
 			return nil, err
 		}
 		return &state, nil