node-apollo-client

node-apollo-client

node apollo client for Ctrip Apollo

Features:

• implement all APIs described in official documentation
• high availability by caching configs in local files which simulate JAVA SDK does.
• written in TypeScript and typing support
• naturally async await function calling, no event or callback mixed-in.

client logic and availability

local configs object
  \-+= local cached config files
    \-+= fetch from Apollo DB at once
      \-+= fetch from Apollo cache periodically (default to 5 minutes)
        \-+= subscribe notification and fetch from Apollo DB if release tag changed
          \-+= update local configs by API: refreshConfigs

scene	influence	configs source
failed to connect apollo at begining	x	use local configs directly
failed to connect apollo	x	use cached apollo configs
failed to connect apollo and wish to update configs	x	update cached configs temporarily
failed to receive notifications	x	fetch configs periodically fetch from apollo
failed to fetch from apollo cache	x	subscribe notification and fetch from DB

Usage

install package from npm

npm install node-apollo-client

const Apollo = require('node-apollo-client')

// Instantiate Apollo
const apollo = new Apollo({
  configServerUrl: 'your-config-server-url',
  appId: 'your-app-id',
  cluster: 'default', // [optional] default to `default`
  namespaces: ['application'],  // default to `['application']`, this is the namespaces that you want to use or maintain.
  initialConfigs: {
    application: {  // this is default namespace name
      foo: 'Mars',
      bar: 'Jupiter'
    },
  }, // [optional]
  listenOnNotification: true, // [optional] default to true
  fetchCacheInterval: 5 * 60e3, // [optional] default to 5 minutes. can be customize but 30s or shorter time are not acceptable.
  cachedConfigFilePath: '/tmp' // [optional] cached configs path, default to system's tmp directory, for linux it's basically '/tmp'.
});

// fetch single config
await apollo.fetchConfig({ key: 'foo' });
// return 'Mars'

// fetch multiple configs
await apollo.fetchConfigs({ keys: [ 'foo', 'bar' ] });
// return { foo: 'Mars', bar: 'Jupiter' }

// refresh local configs (merely used when Apollo is unavailable)
apollo.refreshConfigs({ configs: { foo: 'Mercury' } });
// check out key `foo`
await apollo.fetchConfig({ key: 'foo' });
// return { foo: 'Mercury' }

License

MIT