Refactoring app DB usage - one DB load per request

packages/backend-core/context.js

@@ -0,0 +1,17 @@
+const {
+  getAppDB,
+  getDevAppDB,
+  getProdAppDB,
+  getAppId,
+  updateAppId,
+  doInAppContext,
+} = require("./src/context")
+
+module.exports = {
+  getAppDB,
+  getDevAppDB,
+  getProdAppDB,
+  getAppId,
+  updateAppId,
+  doInAppContext,
+}

packages/backend-core/db.js

@@ -1,5 +1,6 @@
 module.exports = {
   ...require("./src/db/utils"),
   ...require("./src/db/constants"),
+  ...require("./src/db"),
   ...require("./src/db/views"),
 }

packages/backend-core/deprovision.js

@@ -1 +1 @@
-module.exports = require("./src/tenancy/deprovision")
+module.exports = require("./src/context/deprovision")

packages/backend-core/src/tenancy/FunctionContext.js → packages/backend-core/src/context/FunctionContext.js

@@ -4,8 +4,8 @@ const { newid } = require("../hashing")
 const REQUEST_ID_KEY = "requestId"
 
 class FunctionContext {
-  static getMiddleware(updateCtxFn = null) {
-    const namespace = this.createNamespace()
+  static getMiddleware(updateCtxFn = null, contextName = "session") {
+    const namespace = this.createNamespace(contextName)
 
     return async function (ctx, next) {
       await new Promise(
@@ -24,14 +24,14 @@ class FunctionContext {
     }
   }
 
-  static run(callback) {
-    const namespace = this.createNamespace()
+  static run(callback, contextName = "session") {
+    const namespace = this.createNamespace(contextName)
 
     return namespace.runAndReturn(callback)
   }
 
-  static setOnContext(key, value) {
-    const namespace = this.createNamespace()
+  static setOnContext(key, value, contextName = "session") {
+    const namespace = this.createNamespace(contextName)
     namespace.set(key, value)
   }
 
@@ -55,16 +55,16 @@ class FunctionContext {
     }
   }
 
-  static destroyNamespace() {
+  static destroyNamespace(name = "session") {
     if (this._namespace) {
-      cls.destroyNamespace("session")
+      cls.destroyNamespace(name)
       this._namespace = null
     }
   }
 
-  static createNamespace() {
+  static createNamespace(name = "session") {
     if (!this._namespace) {
-      this._namespace = cls.createNamespace("session")
+      this._namespace = cls.createNamespace(name)
     }
     return this._namespace
   }

packages/backend-core/src/tenancy/deprovision.js → packages/backend-core/src/context/deprovision.js

@@ -1,6 +1,6 @@
 const { getGlobalUserParams, getAllApps } = require("../db/utils")
 const { getDB, getCouch } = require("../db")
-const { getGlobalDB } = require("./tenancy")
+const { getGlobalDB } = require("../tenancy")
 const { StaticDatabases } = require("../db/constants")
 
 const TENANT_DOC = StaticDatabases.PLATFORM_INFO.docs.tenants

packages/backend-core/src/context/index.js

@@ -0,0 +1,195 @@
+const env = require("../environment")
+const { Headers } = require("../../constants")
+const cls = require("./FunctionContext")
+const { getCouch } = require("../db")
+const { getProdAppID, getDevelopmentAppID } = require("../db/conversions")
+const { isEqual } = require("lodash")
+
+// some test cases call functions directly, need to
+// store an app ID to pretend there is a context
+let TEST_APP_ID = null
+
+const ContextKeys = {
+  TENANT_ID: "tenantId",
+  APP_ID: "appId",
+  // whatever the request app DB was
+  CURRENT_DB: "currentDb",
+  // get the prod app DB from the request
+  PROD_DB: "prodDb",
+  // get the dev app DB from the request
+  DEV_DB: "devDb",
+  DB_OPTS: "dbOpts",
+}
+
+exports.DEFAULT_TENANT_ID = "default"
+
+exports.isDefaultTenant = () => {
+  return exports.getTenantId() === exports.DEFAULT_TENANT_ID
+}
+
+exports.isMultiTenant = () => {
+  return env.MULTI_TENANCY
+}
+
+// used for automations, API endpoints should always be in context already
+exports.doInTenant = (tenantId, task) => {
+  return cls.run(() => {
+    // set the tenant id
+    cls.setOnContext(ContextKeys.TENANT_ID, tenantId)
+
+    // invoke the task
+    return task()
+  })
+}
+
+exports.doInAppContext = (appId, task) => {
+  return cls.run(() => {
+    // set the app ID
+    cls.setOnContext(ContextKeys.APP_ID, appId)
+
+    // invoke the task
+    return task()
+  })
+}
+
+exports.updateTenantId = tenantId => {
+  cls.setOnContext(ContextKeys.TENANT_ID, tenantId)
+}
+
+exports.updateAppId = appId => {
+  try {
+    cls.setOnContext(ContextKeys.APP_ID, appId)
+    cls.setOnContext(ContextKeys.PROD_DB, null)
+    cls.setOnContext(ContextKeys.DEV_DB, null)
+    cls.setOnContext(ContextKeys.CURRENT_DB, null)
+    cls.setOnContext(ContextKeys.DB_OPTS, null)
+  } catch (err) {
+    if (env.isTest()) {
+      TEST_APP_ID = appId
+    } else {
+      throw err
+    }
+  }
+}
+
+exports.setTenantId = (
+  ctx,
+  opts = { allowQs: false, allowNoTenant: false }
+) => {
+  let tenantId
+  // exit early if not multi-tenant
+  if (!exports.isMultiTenant()) {
+    cls.setOnContext(ContextKeys.TENANT_ID, this.DEFAULT_TENANT_ID)
+    return
+  }
+
+  const allowQs = opts && opts.allowQs
+  const allowNoTenant = opts && opts.allowNoTenant
+  const header = ctx.request.headers[Headers.TENANT_ID]
+  const user = ctx.user || {}
+  if (allowQs) {
+    const query = ctx.request.query || {}
+    tenantId = query.tenantId
+  }
+  // override query string (if allowed) by user, or header
+  // URL params cannot be used in a middleware, as they are
+  // processed later in the chain
+  tenantId = user.tenantId || header || tenantId
+
+  // Set the tenantId from the subdomain
+  if (!tenantId) {
+    tenantId = ctx.subdomains && ctx.subdomains[0]
+  }
+
+  if (!tenantId && !allowNoTenant) {
+    ctx.throw(403, "Tenant id not set")
+  }
+  // check tenant ID just incase no tenant was allowed
+  if (tenantId) {
+    cls.setOnContext(ContextKeys.TENANT_ID, tenantId)
+  }
+}
+
+exports.isTenantIdSet = () => {
+  const tenantId = cls.getFromContext(ContextKeys.TENANT_ID)
+  return !!tenantId
+}
+
+exports.getTenantId = () => {
+  if (!exports.isMultiTenant()) {
+    return exports.DEFAULT_TENANT_ID
+  }
+  const tenantId = cls.getFromContext(ContextKeys.TENANT_ID)
+  if (!tenantId) {
+    throw Error("Tenant id not found")
+  }
+  return tenantId
+}
+
+exports.getAppId = () => {
+  const foundId = cls.getFromContext(ContextKeys.APP_ID)
+  if (!foundId && env.isTest() && TEST_APP_ID) {
+    return TEST_APP_ID
+  } else {
+    return foundId
+  }
+}
+
+function getDB(key, opts) {
+  const dbOptsKey = `${key}${ContextKeys.DB_OPTS}`
+  let storedOpts = cls.getFromContext(dbOptsKey)
+  let db = cls.getFromContext(key)
+  if (db && isEqual(opts, storedOpts)) {
+    return db
+  }
+  const appId = exports.getAppId()
+  const CouchDB = getCouch()
+  let toUseAppId
+  switch (key) {
+    case ContextKeys.CURRENT_DB:
+      toUseAppId = appId
+      break
+    case ContextKeys.PROD_DB:
+      toUseAppId = getProdAppID(appId)
+      break
+    case ContextKeys.DEV_DB:
+      toUseAppId = getDevelopmentAppID(appId)
+      break
+  }
+  db = new CouchDB(toUseAppId, opts)
+  try {
+    cls.setOnContext(key, db)
+    if (opts) {
+      cls.setOnContext(dbOptsKey, opts)
+    }
+  } catch (err) {
+    if (!env.isTest()) {
+      throw err
+    }
+  }
+  return db
+}
+
+/**
+ * Opens the app database based on whatever the request
+ * contained, dev or prod.
+ */
+exports.getAppDB = opts => {
+  return getDB(ContextKeys.CURRENT_DB, opts)
+}
+
+/**
+ * This specifically gets the prod app ID, if the request
+ * contained a development app ID, this will open the prod one.
+ */
+exports.getProdAppDB = opts => {
+  return getDB(ContextKeys.PROD_DB, opts)
+}
+
+/**
+ * This specifically gets the dev app ID, if the request
+ * contained a prod app ID, this will open the dev one.
+ */
+exports.getDevAppDB = opts => {
+  return getDB(ContextKeys.DEV_DB, opts)
+}

packages/backend-core/src/db/constants.js

@@ -32,3 +32,7 @@ exports.StaticDatabases = {
     },
   },
 }
+
+exports.APP_PREFIX = exports.DocumentTypes.APP + exports.SEPARATOR
+exports.APP_DEV = exports.APP_DEV_PREFIX =
+  exports.DocumentTypes.APP_DEV + exports.SEPARATOR

packages/backend-core/src/db/conversions.js

@@ -0,0 +1,46 @@
+const NO_APP_ERROR = "No app provided"
+const { APP_DEV_PREFIX, APP_PREFIX } = require("./constants")
+
+exports.isDevAppID = appId => {
+  if (!appId) {
+    throw NO_APP_ERROR
+  }
+  return appId.startsWith(APP_DEV_PREFIX)
+}
+
+exports.isProdAppID = appId => {
+  if (!appId) {
+    throw NO_APP_ERROR
+  }
+  return appId.startsWith(APP_PREFIX) && !exports.isDevAppID(appId)
+}
+
+exports.isDevApp = app => {
+  if (!app) {
+    throw NO_APP_ERROR
+  }
+  return exports.isDevAppID(app.appId)
+}
+
+/**
+ * Convert a development app ID to a deployed app ID.
+ */
+exports.getProdAppID = appId => {
+  // if dev, convert it
+  if (appId.startsWith(APP_DEV_PREFIX)) {
+    const id = appId.split(APP_DEV_PREFIX)[1]
+    return `${APP_PREFIX}${id}`
+  }
+  return appId
+}
+
+/**
+ * Convert a deployed app ID to a development app ID.
+ */
+exports.getDevelopmentAppID = appId => {
+  if (!appId.startsWith(APP_DEV_PREFIX)) {
+    const id = appId.split(APP_PREFIX)[1]
+    return `${APP_DEV_PREFIX}${id}`
+  }
+  return appId
+}