Expose deletion of AM config via /multitenant_alertmanager/delete_ten…

…ant_config (#3900)


Co-authored-by: gotjosh <[email protected]>
Signed-off-by: Peter Štibraný <[email protected]>

CHANGELOG.md

@@ -91,6 +91,7 @@
   * `cortex_bucket_store_chunk_pool_returned_bytes_total`
 * [ENHANCEMENT] Alertmanager: load alertmanager configurations from object storage concurrently, and only load necessary configurations, speeding configuration synchronization process and executing fewer "GET object" operations to the storage when sharding is enabled. #3898
 * [ENHANCEMENT] Blocks storage: Ingester can now stream entire chunks instead of individual samples to the querier. At the moment this feature must be explicitly enabled either by using `-ingester.stream-chunks-when-using-blocks` flag or `ingester_stream_chunks_when_using_blocks` (boolean) field in runtime config file, but these configuration options are temporary and will be removed when feature is stable. #3889
+* [ENHANCEMENT] Alertmanager: New endpoint `/multitenant_alertmanager/delete_tenant_config` to delete configuration for tenant identified by `X-Scope-OrgID` header. This is an internal endpoint, available even if Alertmanager API is not enabled by using `-experimental.alertmanager.enable-api`. #3900
 * [BUGFIX] Cortex: Fixed issue where fatal errors and various log messages where not logged. #3778
 * [BUGFIX] HA Tracker: don't track as error in the `cortex_kv_request_duration_seconds` metric a CAS operation intentionally aborted. #3745
 * [BUGFIX] Querier / ruler: do not log "error removing stale clients" if the ring is empty. #3761

docs/api/_index.md

@@ -53,6 +53,7 @@ For the sake of clarity, in this document we have grouped API endpoints by servi
 | [Alertmanager status](#alertmanager-status) | Alertmanager | `GET /multitenant_alertmanager/status` |
 | [Alertmanager ring status](#alertmanager-ring-status) | Alertmanager | `GET /multitenant_alertmanager/ring` |
 | [Alertmanager UI](#alertmanager-ui) | Alertmanager | `GET /<alertmanager-http-prefix>` |
+| [Alertmanager Delete Tenant Configuration](#alertmanager-delete-tenant-configuration) | Alertmanager | `POST /multitenant_alertmanager/delete_tenant_config` |
 | [Get Alertmanager configuration](#get-alertmanager-configuration) | Alertmanager | `GET /api/v1/alerts` |
 | [Set Alertmanager configuration](#set-alertmanager-configuration) | Alertmanager | `POST /api/v1/alerts` |
 | [Delete Alertmanager configuration](#delete-alertmanager-configuration) | Alertmanager | `DELETE /api/v1/alerts` |
@@ -683,6 +684,18 @@ Displays the Alertmanager UI.
 
 _Requires [authentication](#authentication)._
 
+### Alertmanager Delete Tenant Configuration
+
+```
+POST /multitenant_alertmanager/delete_tenant_config
+```
+
+This endpoint deletes configuration for a tenant identified by `X-Scope-OrgID` header.
+It is internal, available even if Alertmanager API is not enabled by using `-experimental.alertmanager.enable-api`.
+The endpoint returns a status code of `200` if the user's configuration has been deleted, or it didn't exist in the first place.
+
+_Requires [authentication](#authentication)._
+
 ### Get Alertmanager configuration
 
 ```

pkg/alertmanager/alertstore/store.go

@@ -37,6 +37,7 @@ type AlertStore interface {
 	SetAlertConfig(ctx context.Context, cfg alertspb.AlertConfigDesc) error
 
 	// DeleteAlertConfig deletes the alertmanager configuration for an user.
+	// If configuration for the user doesn't exist, no error is reported.
 	DeleteAlertConfig(ctx context.Context, user string) error
 }
 

pkg/alertmanager/api.go

@@ -112,6 +112,8 @@ func (am *MultitenantAlertmanager) SetUserConfig(w http.ResponseWriter, r *http.
 	w.WriteHeader(http.StatusCreated)
 }
 
+// DeleteUserConfig is exposed via user-visible API (if enabled, uses DELETE method), but also as an internal endpoint using POST method.
+// Note that if no config exists for a user, StatusOK is returned.
 func (am *MultitenantAlertmanager) DeleteUserConfig(w http.ResponseWriter, r *http.Request) {
 	logger := util_log.WithContext(r.Context(), am.logger)
 	userID, err := tenant.TenantID(r.Context())

pkg/alertmanager/api_test.go

@@ -2,12 +2,18 @@ package alertmanager
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
 	"testing"
 
+	"github.com/go-kit/kit/log"
+	"github.com/thanos-io/thanos/pkg/objstore"
+
+	"github.com/cortexproject/cortex/pkg/alertmanager/alertspb"
+	"github.com/cortexproject/cortex/pkg/alertmanager/alertstore/bucketclient"
 	util_log "github.com/cortexproject/cortex/pkg/util/log"
 
 	"github.com/stretchr/testify/require"
@@ -148,3 +154,48 @@ template_files:
 		})
 	}
 }
+
+func TestMultitenantAlertmanager_DeleteUserConfig(t *testing.T) {
+	storage := objstore.NewInMemBucket()
+	alertStore := bucketclient.NewBucketAlertStore(storage, nil, log.NewNopLogger())
+
+	am := &MultitenantAlertmanager{
+		store:  alertStore,
+		logger: util_log.Logger,
+	}
+
+	require.NoError(t, alertStore.SetAlertConfig(context.Background(), alertspb.AlertConfigDesc{
+		User:      "test_user",
+		RawConfig: "config",
+	}))
+
+	require.Equal(t, 1, len(storage.Objects()))
+
+	req := httptest.NewRequest("POST", "/multitenant_alertmanager/delete_tenant_config", nil)
+	// Missing user returns error 401. (DeleteUserConfig does this, but in practice, authentication middleware will do it first)
+	{
+		rec := httptest.NewRecorder()
+		am.DeleteUserConfig(rec, req)
+		require.Equal(t, http.StatusUnauthorized, rec.Code)
+		require.Equal(t, 1, len(storage.Objects()))
+	}
+
+	// With user in the context.
+	ctx := user.InjectOrgID(context.Background(), "test_user")
+	req = req.WithContext(ctx)
+	{
+		rec := httptest.NewRecorder()
+		am.DeleteUserConfig(rec, req)
+		require.Equal(t, http.StatusOK, rec.Code)
+		require.Equal(t, 0, len(storage.Objects()))
+	}
+
+	// Repeating the request still reports 200
+	{
+		rec := httptest.NewRecorder()
+		am.DeleteUserConfig(rec, req)
+
+		require.Equal(t, http.StatusOK, rec.Code)
+		require.Equal(t, 0, len(storage.Objects()))
+	}
+}

pkg/api/api.go

@@ -167,6 +167,7 @@ func (a *API) RegisterAlertmanager(am *alertmanager.MultitenantAlertmanager, tar
 	// Ensure this route is registered before the prefixed AM route
 	a.RegisterRoute("/multitenant_alertmanager/status", am.GetStatusHandler(), false, "GET")
 	a.RegisterRoute("/multitenant_alertmanager/ring", http.HandlerFunc(am.RingHandler), false, "GET", "POST")
+	a.RegisterRoute("/multitenant_alertmanager/delete_tenant_config", http.HandlerFunc(am.DeleteUserConfig), true, "POST")
 
 	// UI components lead to a large number of routes to support, utilize a path prefix instead
 	a.RegisterRoutesWithPrefix(a.cfg.AlertmanagerHTTPPrefix, am, true)