Alerting: Refactor GET/POST alerting config routes to be more extensible (#47229)

* Refactor GET am config to be extensible * Extract post config route * Fix tests * Remove temporary duplication * Fix broken test due to layer shift * Fix duplicated error message * Properly return 400 on config rejection * Revert weird half method extraction * Move things to notifier package and avoid redundant interface * Simplify documentation * Split encryption service and depend on minimal abstractions * Properly initialize things all the way up to the composition root * Encryption -> Crypto * Address misc feedback * Missing docstring * Few more simple polish improvements * Unify on MultiOrgAlertmanager. Discover bug in existing test * Fix rebase conflicts * Misc feedback, renames, docs * Access crypto hanging off MultiOrgAlertmanager rather than having a separate API to initialize
2022-04-14 13:06:21 -05:00
parent a126c07e54
commit 758364e78b
10 changed files with 283 additions and 177 deletions
@@ -0,0 +1,118 @@
+package notifier
+
+import (
+	"context"
+	"encoding/base64"
+	"errors"
+	"fmt"
+
+	"github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/services/ngalert/api/tooling/definitions"
+	"github.com/grafana/grafana/pkg/services/ngalert/models"
+	"github.com/grafana/grafana/pkg/services/ngalert/store"
+	"github.com/grafana/grafana/pkg/services/secrets"
+)
+
+// Crypto allows decryption of Alertmanager Configuration and encryption of arbitrary payloads.
+type Crypto interface {
+	LoadSecureSettings(ctx context.Context, orgId int64, receivers []*definitions.PostableApiReceiver) error
+	Encrypt(ctx context.Context, payload []byte, opt secrets.EncryptionOptions) ([]byte, error)
+
+	getDecryptedSecret(r *definitions.PostableGrafanaReceiver, key string) (string, error)
+}
+
+// alertmanagerCrypto implements decryption of Alertmanager configuration and encryption of arbitrary payloads based on Grafana's encryptions.
+type alertmanagerCrypto struct {
+	secrets secrets.Service
+	configs configurationStore
+	log     log.Logger
+}
+
+func NewCrypto(secrets secrets.Service, configs configurationStore, log log.Logger) Crypto {
+	return &alertmanagerCrypto{
+		secrets: secrets,
+		configs: configs,
+		log:     log,
+	}
+}
+
+// LoadSecureSettings adds the corresponding unencrypted secrets stored to the list of input receivers.
+func (c *alertmanagerCrypto) LoadSecureSettings(ctx context.Context, orgId int64, receivers []*definitions.PostableApiReceiver) error {
+	// Get the last known working configuration.
+	query := models.GetLatestAlertmanagerConfigurationQuery{OrgID: orgId}
+	if err := c.configs.GetLatestAlertmanagerConfiguration(ctx, &query); err != nil {
+		// If we don't have a configuration there's nothing for us to know and we should just continue saving the new one.
+		if !errors.Is(err, store.ErrNoAlertmanagerConfiguration) {
+			return fmt.Errorf("failed to get latest configuration: %w", err)
+		}
+	}
+
+	currentReceiverMap := make(map[string]*definitions.PostableGrafanaReceiver)
+	if query.Result != nil {
+		currentConfig, err := Load([]byte(query.Result.AlertmanagerConfiguration))
+		// If the current config is un-loadable, treat it as if it never existed. Providing a new, valid config should be able to "fix" this state.
+		if err != nil {
+			c.log.Warn("Last known alertmanager configuration was invalid. Overwriting...")
+		} else {
+			currentReceiverMap = currentConfig.GetGrafanaReceiverMap()
+		}
+	}
+
+	// Copy the previously known secure settings.
+	for i, r := range receivers {
+		for j, gr := range r.PostableGrafanaReceivers.GrafanaManagedReceivers {
+			if gr.UID == "" { // new receiver
+				continue
+			}
+
+			cgmr, ok := currentReceiverMap[gr.UID]
+			if !ok {
+				// It tries to update a receiver that didn't previously exist
+				return UnknownReceiverError{UID: gr.UID}
+			}
+
+			// Frontend sends only the secure settings that have to be updated
+			// Therefore we have to copy from the last configuration only those secure settings not included in the request
+			for key := range cgmr.SecureSettings {
+				_, ok := gr.SecureSettings[key]
+				if !ok {
+					decryptedValue, err := c.getDecryptedSecret(cgmr, key)
+					if err != nil {
+						return fmt.Errorf("failed to decrypt stored secure setting: %s: %w", key, err)
+					}
+
+					if receivers[i].PostableGrafanaReceivers.GrafanaManagedReceivers[j].SecureSettings == nil {
+						receivers[i].PostableGrafanaReceivers.GrafanaManagedReceivers[j].SecureSettings = make(map[string]string, len(cgmr.SecureSettings))
+					}
+
+					receivers[i].PostableGrafanaReceivers.GrafanaManagedReceivers[j].SecureSettings[key] = decryptedValue
+				}
+			}
+		}
+	}
+	return nil
+}
+
+func (c *alertmanagerCrypto) getDecryptedSecret(r *definitions.PostableGrafanaReceiver, key string) (string, error) {
+	storedValue, ok := r.SecureSettings[key]
+	if !ok {
+		return "", nil
+	}
+
+	decodeValue, err := base64.StdEncoding.DecodeString(storedValue)
+	if err != nil {
+		return "", err
+	}
+
+	decryptedValue, err := c.secrets.Decrypt(context.Background(), decodeValue)
+	if err != nil {
+		return "", err
+	}
+
+	return string(decryptedValue), nil
+}
+
+// Encrypt delegates encryption to secrets.Service.
+func (c *alertmanagerCrypto) Encrypt(ctx context.Context, payload []byte, opt secrets.EncryptionOptions) ([]byte, error) {
+	return c.secrets.Encrypt(ctx, payload, opt)
+}