Merge pull request #69 from leapfrogtechnology/resolver

Support connection resolver

Author: kabirbaidhya

src/commands/migrate-latest.ts

@@ -14,6 +14,10 @@ class MigrateLatest extends Command {
     only: flags.string({
       helpValue: 'CONNECTION_ID',
       description: 'Filter only a single connection.'
+    }),
+    'connection-resolver': flags.string({
+      helpValue: 'PATH',
+      description: 'Path to the connection resolver.'
     })
   };
 
@@ -60,7 +64,7 @@ class MigrateLatest extends Command {
   async run(): Promise<void> {
     const { flags: parsedFlags } = this.parse(MigrateLatest);
     const config = await loadConfig();
-    const connections = await resolveConnections();
+    const connections = await resolveConnections(config, parsedFlags['connection-resolver']);
 
     const results = await migrateLatest(config, connections, {
       ...parsedFlags,

src/commands/migrate-list.ts

@@ -13,6 +13,10 @@ class MigrateList extends Command {
     only: flags.string({
       helpValue: 'CONNECTION_ID',
       description: 'Filter only a single connection.'
+    }),
+    'connection-resolver': flags.string({
+      helpValue: 'PATH',
+      description: 'Path to the connection resolver.'
     })
   };
 
@@ -64,7 +68,7 @@ class MigrateList extends Command {
   async run(): Promise<void> {
     const { flags: parsedFlags } = this.parse(MigrateList);
     const config = await loadConfig();
-    const connections = await resolveConnections();
+    const connections = await resolveConnections(config, parsedFlags['connection-resolver']);
 
     const results = await migrateList(config, connections, {
       ...parsedFlags,

src/commands/migrate-rollback.ts

@@ -14,6 +14,10 @@ class MigrateRollback extends Command {
     only: flags.string({
       helpValue: 'CONNECTION_ID',
       description: 'Filter only a single connection.'
+    }),
+    'connection-resolver': flags.string({
+      helpValue: 'PATH',
+      description: 'Path to the connection resolver.'
     })
   };
 
@@ -60,7 +64,7 @@ class MigrateRollback extends Command {
   async run(): Promise<void> {
     const { flags: parsedFlags } = this.parse(MigrateRollback);
     const config = await loadConfig();
-    const connections = await resolveConnections();
+    const connections = await resolveConnections(config, parsedFlags['connection-resolver']);
 
     const results = await migrateRollback(config, connections, {
       ...parsedFlags,

src/commands/prune.ts

@@ -13,6 +13,10 @@ class Prune extends Command {
     only: flags.string({
       helpValue: 'CONNECTION_ID',
       description: 'Filter only a single connection.'
+    }),
+    'connection-resolver': flags.string({
+      helpValue: 'PATH',
+      description: 'Path to the connection resolver.'
     })
   };
 
@@ -40,7 +44,7 @@ class Prune extends Command {
   async run(): Promise<void> {
     const { flags: parsedFlags } = this.parse(Prune);
     const config = await loadConfig();
-    const connections = await resolveConnections();
+    const connections = await resolveConnections(config, parsedFlags['connection-resolver']);
 
     const results = await prune(config, connections, {
       ...parsedFlags,

src/commands/synchronize.ts

@@ -15,11 +15,15 @@ class Synchronize extends Command {
    * Available CLI flags.
    */
   static flags = {
-    force: flags.boolean({ char: 'f', description: 'Force synchronization' }),
-    'skip-migration': flags.boolean({ description: 'Skip running migrations' }),
+    force: flags.boolean({ char: 'f', description: 'Force synchronization.' }),
+    'skip-migration': flags.boolean({ description: 'Skip running migrations.' }),
     only: flags.string({
       helpValue: 'CONNECTION_ID',
       description: 'Filter only a single connection.'
+    }),
+    'connection-resolver': flags.string({
+      helpValue: 'PATH',
+      description: 'Path to the connection resolver.'
     })
   };
 
@@ -127,7 +131,7 @@ class Synchronize extends Command {
 
     try {
       const config = await loadConfig();
-      const connections = await resolveConnections();
+      const connections = await resolveConnections(config, parsedFlags['connection-resolver']);
       const timeStart = process.hrtime();
 
       await printLine('Synchronizing...\n');

src/config.ts

@@ -11,6 +11,10 @@ import ConnectionsFileSchema from './domain/ConnectionsFileSchema';
 import { prepareInjectionConfigVars } from './service/configInjection';
 import { DEFAULT_CONFIG, CONFIG_FILENAME, CONNECTIONS_FILENAME, REQUIRED_ENV_KEYS } from './constants';
 
+interface ConnectionResolver {
+  resolve: () => Promise<ConnectionConfig[]>;
+}
+
 /**
  * Check if this is being run via the sync-db cli or not.
  *
@@ -88,18 +92,23 @@ export function validate(config: Configuration) {
  *
  * @returns {Promise<ConnectionConfig[]>}
  */
-export async function resolveConnections(): Promise<ConnectionConfig[]> {
+
+export async function resolveConnections(config: Configuration, resolver?: string): Promise<ConnectionConfig[]> {
   log('Resolving database connections.');
 
   const filename = path.resolve(process.cwd(), CONNECTIONS_FILENAME);
   const connectionsFileExists = await fs.exists(filename);
 
-  let connections;
+  let connections: ConnectionConfig[];
 
-  // If connections file exists, resolve connections from that.
-  // otherwise fallback to getting the connection from the env vars.
+  // Connection resolution process:
+  //  1. If connections file exists, use that to resolve connections.
+  //  2. If connection resolver is set via flag or configuration, use it.
+  //  3. If 1 & 2 are false, try resolving the connections from the environment. If not found fail with error.
   if (connectionsFileExists) {
     connections = await resolveConnectionsFromFile(filename);
+  } else if (resolver || config.connectionResolver) {
+    connections = await resolveConnectionsUsingResolver(resolver || config.connectionResolver);
   } else {
     log('Connections file not provided.');
 
@@ -121,6 +130,27 @@ export async function resolveConnections(): Promise<ConnectionConfig[]> {
   return connections;
 }
 
+/**
+ * Resolve connections using the provided connection resolver.
+ *
+ * @param {Configuration} config
+ * @param {string} resolver
+ * @returns {Promise<ConnectionConfig[]>}
+ */
+export async function resolveConnectionsUsingResolver(resolver: string): Promise<ConnectionConfig[]> {
+  log('Resolving connection resolver: %s', resolver);
+
+  const resolverPath = resolver ? path.resolve(process.cwd(), resolver) : '';
+
+  const { resolve } = (await import(resolverPath)) as ConnectionResolver;
+
+  if (!resolve) {
+    throw new Error(`Resolver '${resolver}' does not expose a 'resolve' function.`);
+  }
+
+  return resolve();
+}
+
 /**
  * Get the connection id from the config.
  *
@@ -186,7 +216,7 @@ export function resolveConnectionsFromEnv(): ConnectionConfig[] {
  * @returns {Promise<ConnectionConfig[]>}
  */
 async function resolveConnectionsFromFile(filename: string): Promise<ConnectionConfig[]> {
-  log('Resolving file: %s', filename);
+  log('Resolving connections file: %s', filename);
 
   const loaded = await fs.read(filename);
   const { connections } = JSON.parse(loaded) as ConnectionsFileSchema;

src/constants.ts

@@ -14,6 +14,7 @@ export const CONNECTIONS_FILENAME = 'connections.sync-db.json';
 export const INJECTED_CONFIG_TABLE = '__sync_db_injected_config';
 export const DEFAULT_CONFIG: Configuration = {
   basePath: path.resolve(process.cwd(), 'src'),
+  connectionResolver: '',
   execution: 'parallel',
   sql: [],
   hooks: {

src/domain/Configuration.ts

@@ -7,6 +7,7 @@ interface Configuration {
   basePath: string;
   execution: 'parallel' | 'sequential';
   sql: string[];
+  connectionResolver: string;
   hooks: {
     pre_sync: string[];
     post_sync: string[];