Fix linter

component/mimir/rules/diff.go

@@ -31,10 +31,7 @@ func diffRuleState(desired map[string][]mimirClient.RuleGroup, actual map[string
 		seen[namespace] = true
 
 		actualRuleGroups := actual[namespace]
-		subDiff, err := diffRuleNamespaceState(desiredRuleGroups, actualRuleGroups)
-		if err != nil {
-			return nil, err
-		}
+		subDiff := diffRuleNamespaceState(desiredRuleGroups, actualRuleGroups)
 
 		if len(subDiff) == 0 {
 			continue
@@ -48,18 +45,15 @@ func diffRuleState(desired map[string][]mimirClient.RuleGroup, actual map[string
 			continue
 		}
 
-		subDiff, err := diffRuleNamespaceState(nil, actualRuleGroups)
-		if err != nil {
-			return nil, err
-		}
+		subDiff := diffRuleNamespaceState(nil, actualRuleGroups)
 
 		diff[namespace] = subDiff
 	}
 
 	return diff, nil
 }
 
-func diffRuleNamespaceState(desired []mimirClient.RuleGroup, actual []mimirClient.RuleGroup) ([]ruleGroupDiff, error) {
+func diffRuleNamespaceState(desired []mimirClient.RuleGroup, actual []mimirClient.RuleGroup) []ruleGroupDiff {
 	var diff []ruleGroupDiff
 
 	seenGroups := map[string]bool{}
@@ -100,7 +94,7 @@ desiredGroups:
 		})
 	}
 
-	return diff, nil
+	return diff
 }
 
 func equalRuleGroups(a, b mimirClient.RuleGroup) bool {

component/mimir/rules/diff_test.go

@@ -158,7 +158,6 @@ func requireEqualRuleDiffs(t *testing.T, expected, actual map[string][]ruleGroup
 				t.Logf("actual diff: %s", summarizeDiff(actualDiff))
 				t.Fail()
 			}
-
 		}
 	}
 }

component/mimir/rules/events.go

@@ -139,6 +139,9 @@ func (c *Component) reconcileState(ctx context.Context) error {
 	defer cancel()
 
 	desiredState, err := c.loadStateFromK8s()
+	if err != nil {
+		return err
+	}
 
 	diffs, err := diffRuleState(desiredState, c.currentState)
 	if err != nil {
@@ -238,16 +241,14 @@ func (c *Component) applyChanges(ctx context.Context, namespace string, diffs []
 	}
 
 	// resync mimir state after applying changes
-	c.syncMimir(ctx)
-
-	return nil
+	return c.syncMimir(ctx)
 }
 
 // mimirNamespaceForRuleCRD returns the namespace that the rule CRD should be
 // stored in mimir. This function, along with isManagedNamespace, is used to
 // determine if a rule CRD is managed by the agent.
 func mimirNamespaceForRuleCRD(prefix string, pr *promv1.PrometheusRule) string {
-	return fmt.Sprintf("agent/%s/%s/%s", pr.Namespace, pr.Name, pr.UID)
+	return fmt.Sprintf("%s/%s/%s/%s", prefix, pr.Namespace, pr.Name, pr.UID)
 }
 
 // isManagedMimirNamespace returns true if the namespace is managed by the agent.

component/mimir/rules/rules.go

@@ -10,7 +10,6 @@ import (
 	"github.com/go-kit/log/level"
 	"github.com/grafana/agent/component"
 	mimirClient "github.com/grafana/agent/pkg/mimir/client"
-	"github.com/pkg/errors"
 	promListers "github.com/prometheus-operator/prometheus-operator/pkg/client/listers/monitoring/v1"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/weaveworks/common/instrument"
@@ -131,7 +130,10 @@ var _ component.HealthComponent = (*Component)(nil)
 
 func NewComponent(o component.Options, args Arguments) (*Component, error) {
 	metrics := newMetrics()
-	metrics.Register(o.Registerer)
+	err := metrics.Register(o.Registerer)
+	if err != nil {
+		return nil, fmt.Errorf("registering metrics failed: %w", err)
+	}
 
 	c := &Component{
 		log:           o.Logger,
@@ -142,16 +144,20 @@ func NewComponent(o component.Options, args Arguments) (*Component, error) {
 		metrics:       metrics,
 	}
 
-	err := c.init()
+	err = c.init()
 	if err != nil {
-		return nil, errors.Wrap(err, "initializing component")
+		return nil, fmt.Errorf("initializing component failed: %w", err)
 	}
 
 	return c, nil
 }
 
 func (c *Component) Run(ctx context.Context) error {
-	c.startup(ctx)
+	err := c.startup(ctx)
+	if err != nil {
+		level.Error(c.log).Log("msg", "starting up component failed", "err", err)
+		c.reportUnhealthy(err)
+	}
 
 	for {
 		select {
@@ -161,13 +167,22 @@ func (c *Component) Run(ctx context.Context) error {
 
 			c.args = update.args
 			err := c.init()
-			update.err <- err
 			if err != nil {
 				level.Error(c.log).Log("msg", "updating configuration failed", "err", err)
 				c.reportUnhealthy(err)
+				update.err <- err
+				continue
 			}
 
-			c.startup(ctx)
+			err = c.startup(ctx)
+			if err != nil {
+				level.Error(c.log).Log("msg", "updating configuration failed", "err", err)
+				c.reportUnhealthy(err)
+				update.err <- err
+				continue
+			}
+
+			update.err <- nil
 		case <-ctx.Done():
 			c.shutdown()
 			return nil
@@ -180,14 +195,18 @@ func (c *Component) Run(ctx context.Context) error {
 }
 
 // startup launches the informers and starts the event loop.
-func (c *Component) startup(ctx context.Context) {
+func (c *Component) startup(ctx context.Context) error {
 	c.queue = workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "mimir.rules.kubernetes")
 	c.informerStopChan = make(chan struct{})
 
 	c.startNamespaceInformer()
 	c.startRuleInformer()
-	c.syncMimir(ctx)
+	err := c.syncMimir(ctx)
+	if err != nil {
+		return err
+	}
 	go c.eventLoop(ctx)
+	return nil
 }
 
 func (c *Component) shutdown() {

pkg/mimir/client/client.go

@@ -4,14 +4,14 @@ import (
 	"bufio"
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
 	"net/url"
 	"strings"
 
 	log "github.com/go-kit/log"
-	"github.com/pkg/errors"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	weaveworksClient "github.com/weaveworks/common/http/client"
@@ -98,7 +98,7 @@ func (r *MimirClient) doRequest(operation, path, method string, payload []byte)
 
 	if err := checkResponse(resp); err != nil {
 		_ = resp.Body.Close()
-		return nil, errors.Wrapf(err, "%s request to %s failed", req.Method, req.URL.String())
+		return nil, fmt.Errorf("error %s %s: %w", method, path, err)
 	}
 
 	return resp, nil

pkg/mimir/client/client_test.go

@@ -91,5 +91,4 @@ func TestBuildURL(t *testing.T) {
 			require.Equal(t, tt.resultURL, req.URL.String())
 		})
 	}
-
 }

pkg/mimir/client/rules_test.go

@@ -72,5 +72,4 @@ func TestMimirClient_X(t *testing.T) {
 			require.Equal(t, tc.expURLPath, req.URL.EscapedPath())
 		})
 	}
-
 }