rf: ZENKO-1531 move replication info logic

Move logic for getting replication info from Cloudserver
to Arsenal. Plan to use same logic in backbeat

index.js

@@ -80,6 +80,7 @@ module.exports = {
         },
         prepareStream: require('./lib/s3middleware/prepareStream'),
         processMpuParts: require('./lib/s3middleware/processMpuParts'),
+        replicationInfo: require('./lib/s3middleware/replicationInfo'),
     },
     storage: {
         metadata: {

lib/s3middleware/replicationInfo.js

@@ -0,0 +1,76 @@
+const { replicationBackends } = require('../constants');
+
+function _getBackend(objectMD, site) {
+    const backends = objectMD ? objectMD.replicationInfo.backends : [];
+    const backend = backends.find(o => o.site === site);
+    // If the backend already exists, just update the status.
+    if (backend) {
+        return Object.assign({}, backend, { status: 'PENDING' });
+    }
+    return {
+        site,
+        status: 'PENDING',
+        dataStoreVersionId: '',
+    };
+}
+
+function _getStorageClasses(rule, replicationEndpoints) {
+    if (rule.storageClass) {
+        return rule.storageClass.split(',');
+    }
+    // If no storage class, use the given default endpoint or the sole endpoint
+    if (replicationEndpoints.length > 1) {
+        const endPoint =
+            replicationEndpoints.find(endpoint => endpoint.default);
+        return [endPoint.site];
+    }
+    return [replicationEndpoints[0].site];
+}
+
+/**
+ * Get replication information
+ * @param {Object} rule - applicable replication rule
+ * @param {String} rule.storageClass - comma separated list of storage classes
+ * @param {Object} replicationConfig - replication config set on bucket metadata
+ * @param {Array} content - replication content
+ * @param {String} operationType - type of operation to replicate
+ * @param {Object} objectMD - object metadata
+ * @param {Object} bucketMD - bucket metadata
+ * @param {Object} config - config fields by environment
+ * @param {Object} config.locationConstraints - location constraints
+ * @param {Array} [config.replicationEndpoints] - replication endpoints used if
+ *   no storage classes defined on rule. Used by cloudserver
+ * @return {Object} replicationInfo
+ */
+function getReplicationInfoObject(rule, replicationConfig, content,
+    operationType, objectMD, bucketMD, config) {
+    const { replicationEndpoints } = config;
+    const storageTypes = [];
+    const backends = [];
+    const storageClasses = _getStorageClasses(rule, replicationEndpoints);
+    storageClasses.forEach(storageClass => {
+        const storageClassName =
+              storageClass.endsWith(':preferred_read') ?
+              storageClass.split(':')[0] : storageClass;
+        const location = config.locationConstraints[storageClassName];
+        if (location && replicationBackends[location.type]) {
+            storageTypes.push(location.type);
+        }
+        backends.push(_getBackend(objectMD, storageClassName));
+    });
+    if (storageTypes.length > 0 && operationType) {
+        content.push(operationType);
+    }
+    return {
+        status: 'PENDING',
+        backends,
+        content,
+        destination: replicationConfig.destination,
+        storageClass: storageClasses.join(','),
+        role: replicationConfig.role,
+        storageType: storageTypes.join(','),
+        isNFS: bucketMD.isNFS(),
+    };
+}
+
+module.exports = { getReplicationInfoObject };