Move Elasticsearch to source available 🎉 🎉 (#29015)

* Move Elasticsearch to source available

server/enterprise/elasticsearch/opensearch/common.go

@@ -0,0 +1,124 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.enterprise for license information.
+
+package opensearch
+
+import (
+	"crypto/tls"
+	"net/http"
+	"time"
+
+	"github.com/opensearch-project/opensearch-go/v4"
+	"github.com/opensearch-project/opensearch-go/v4/opensearchapi"
+
+	"github.com/mattermost/mattermost/server/public/model"
+	"github.com/mattermost/mattermost/server/public/shared/mlog"
+	"github.com/mattermost/mattermost/server/v8/enterprise/elasticsearch/common"
+	"github.com/mattermost/mattermost/server/v8/platform/shared/filestore"
+)
+
+func createClient(logger mlog.LoggerIFace, cfg *model.Config, fileBackend filestore.FileBackend, debugLogging bool) (*opensearchapi.Client, *model.AppError) {
+	esCfg, appErr := createClientConfig(logger, cfg, fileBackend, debugLogging)
+	if appErr != nil {
+		return nil, appErr
+	}
+
+	client, err := opensearchapi.NewClient(*esCfg)
+	if err != nil {
+		return nil, model.NewAppError("Elasticsearch.createClient", "ent.elasticsearch.create_client.connect_failed", nil, "", http.StatusInternalServerError).Wrap(err)
+	}
+
+	return client, nil
+}
+
+func createClientConfig(logger mlog.LoggerIFace, cfg *model.Config, fileBackend filestore.FileBackend, debugLogging bool) (*opensearchapi.Config, *model.AppError) {
+	tp := http.DefaultTransport.(*http.Transport).Clone()
+	tp.TLSClientConfig = &tls.Config{
+		InsecureSkipVerify: *cfg.ElasticsearchSettings.SkipTLSVerification,
+	}
+
+	osCfg := &opensearchapi.Config{
+		Client: opensearch.Config{
+			Addresses:            []string{*cfg.ElasticsearchSettings.ConnectionURL},
+			RetryBackoff:         func(i int) time.Duration { return time.Duration(i) * 100 * time.Millisecond }, // A minimal backoff function
+			RetryOnStatus:        []int{502, 503, 504, 429},                                                      // Retry on 429 TooManyRequests statuses
+			MaxRetries:           3,
+			DiscoverNodesOnStart: *cfg.ElasticsearchSettings.Sniff,
+		},
+	}
+
+	if osCfg.Client.DiscoverNodesOnStart {
+		osCfg.Client.DiscoverNodesInterval = 30 * time.Second
+	}
+
+	if *cfg.ElasticsearchSettings.ClientCert != "" {
+		appErr := configureClientCertificate(tp.TLSClientConfig, cfg, fileBackend)
+		if appErr != nil {
+			return nil, appErr
+		}
+	}
+
+	// custom CA
+	if *cfg.ElasticsearchSettings.CA != "" {
+		appErr := configureCA(&osCfg.Client, cfg, fileBackend)
+		if appErr != nil {
+			return nil, appErr
+		}
+	}
+
+	osCfg.Client.Transport = tp
+
+	if *cfg.ElasticsearchSettings.Username != "" {
+		osCfg.Client.Username = *cfg.ElasticsearchSettings.Username
+		osCfg.Client.Password = *cfg.ElasticsearchSettings.Password
+	}
+
+	// This is a compatibility mode from previous config settings.
+	// We have to conditionally enable debug logging due to
+	// https://github.com/elastic/elastic-transport-go/issues/22
+	// Although, this is opensearch, the issue is the same.
+	if *cfg.ElasticsearchSettings.Trace == "all" && debugLogging {
+		osCfg.Client.EnableDebugLogger = true
+	}
+
+	osCfg.Client.Logger = common.NewLogger("Opensearch", logger, *cfg.ElasticsearchSettings.Trace == "all")
+
+	return osCfg, nil
+}
+
+func configureCA(esCfg *opensearch.Config, cfg *model.Config, fb filestore.FileBackend) *model.AppError {
+	// read the certificate authority (CA) file
+	clientCA, err := common.ReadFileSafely(fb, *cfg.ElasticsearchSettings.CA)
+	if err != nil {
+		return model.NewAppError("Elasticsearch.createClient", "ent.elasticsearch.create_client.ca_cert_missing", nil, "", http.StatusInternalServerError).Wrap(err)
+	}
+
+	esCfg.CACert = clientCA
+
+	return nil
+}
+
+func configureClientCertificate(tlsConfig *tls.Config, cfg *model.Config, fb filestore.FileBackend) *model.AppError {
+	// read the client certificate file
+	clientCert, err := common.ReadFileSafely(fb, *cfg.ElasticsearchSettings.ClientCert)
+	if err != nil {
+		return model.NewAppError("Elasticsearch.createClient", "ent.elasticsearch.create_client.client_cert_missing", nil, "", http.StatusInternalServerError).Wrap(err)
+	}
+
+	// read the client key file
+	clientKey, err := common.ReadFileSafely(fb, *cfg.ElasticsearchSettings.ClientKey)
+	if err != nil {
+		return model.NewAppError("Elasticsearch.createClient", "ent.elasticsearch.create_client.client_key_missing", nil, "", http.StatusInternalServerError).Wrap(err)
+	}
+
+	// load the client key and certificate
+	certificate, err := tls.X509KeyPair(clientCert, clientKey)
+	if err != nil {
+		return model.NewAppError("Elasticsearch.createClient", "ent.elasticsearch.create_client.client_cert_malformed", nil, "", http.StatusInternalServerError).Wrap(err)
+	}
+
+	// update the TLS config
+	tlsConfig.Certificates = []tls.Certificate{certificate}
+
+	return nil
+}