Gizmo Microservice Toolkit

As of late April, 2021 Gizmo has been placed in maintenance mode.

This toolkit provides packages to put together server and pubsub daemons with the following features:

• Standardized configuration and logging
• Health check endpoints with configurable strategies
• Configuration for managing pprof endpoints and log levels
• Basic interfaces to define expectations and vocabulary
• Structured logging containing basic request information
• Useful metrics for endpoints
• Graceful shutdowns

Install

Notice the capitalization!

go get github.com/NYTimes/gizmo/...

Import Path Change Notice

The New York Times recently changed the github organization from NYTimes to nytimes. This should not affect the installation as long as you use the proper casing NYTimes and not nytimes per installation instructions above.

However, the intention is to migrate the import paths to be consistent with how it’s shown on GitHub. This will be a breaking change and we will introduce a major tag when we update the code. Therefore, the import path will go from github.com/NYTimes/gizmo/server to github.com/nytimes/gizmo/v2/server. This ensures that people will not have type-mismatches between import path changes.

Packages

The server package is the bulk of the toolkit and relies on server.Config to manage Server implementations.

It offers 1 server implementation:

SimpleServer, which is capable of handling basic HTTP and JSON requests via 5 of the available Service implementations: SimpleService, JSONService, ContextService, MixedService and a MixedContextService.

The server/kit package embodies Gizmo’s goals to combine with go-kit.

• In this package you’ll find:
  • A more opinionated server with fewer choices.
  • go-kit used for serving HTTP/JSON & gRPC used for serving HTTP2/RPC
  • Monitoring, traces and metrics are automatically registered if running within App Engine, Cloud Run, Kubernetes Engine, Compute Engine or AWS EC2 Instances.
    • to change the name and version for Error reporting and Traces use SERVICE_NAME and SERVICE_VERSION environment variables.
  • Logs go to stdout locally or directly to Stackdriver when in GCP.
  • Using Go’s 1.8 graceful HTTP shutdown.
  • Services using this package are expected to deploy to GCP.

The observe package provides observability helpers for metrics and tracing through OpenCensus

• server/kit (and soon SimpleServer) utilizes this package to create a StackDriver exporter with sane defaults
• GoogleProjectID, IsGAE, and IsCloudRun can help you make decisions about the underlying platform

The auth package provides primitives for verifying inbound authentication tokens:

• The PublicKeySource interface is meant to provide *rsa.PublicKeys from JSON Web Key Sets.
• The Verifier struct composes key source implementations with custom decoders and verifier functions to streamline server side token verification.

The auth/gcp package provides 2 Google Cloud Platform based auth.PublicKeySource and oauth2.TokenSource implementations:

• The “Identity” key source and token source rely on GCP’s identity JWT mechanism for asserting instance identities. This is the preferred method for asserting instance identity on GCP.
• The “IAM” key source and token source rely on GCP’s IAM services for signing and verifying JWTs. This method can be used outside of GCP, if needed and can provide a bridge for users transitioning from the 1st generation App Engine (where Identity tokens are not available) runtime to the 2nd.

The auth/gcp package also includes an Authenticator, which encapsulates a Google Identity verifier and oauth2 credentials to manage a basic web auth flow.

The config package contains a handful of useful functions to load to configuration structs from JSON files or environment variables.

There are also many structs for common configuration options and credentials of different Cloud Services and Databases.

The pubsub package contains two (publisher and subscriber) generic interfaces for publishing data to queues as well as subscribing and consuming data from those queues.

There are 4 implementations of pubsub interfaces:

• For pubsub via Amazon’s SNS/SQS, you can use the pubsub/aws package

• For pubsub via Google’s Pubsub, you can use the pubsub/gcp package

• For pubsub via Kafka topics, you can use the pubsub/kafka package

• For publishing via HTTP, you can use the pubsub/http package

The pubsub/pubsubtest package contains test implementations of the pubsub.Publisher, pubsub.MultiPublisher, and pubsub.Subscriber interfaces that will allow developers to easily mock out and test their pubsub implementations.

Examples

• Several reference implementations utilizing server and pubsub are available in the examples subdirectory.
• There are also examples within the GoDoc: here

If you experience any issues please create an issue and/or reach out on the #gizmo channel in the Gophers Slack Workspace with what you’ve found.

The Gizmo logo was based on the Go mascot designed by Renée French and copyrighted under the Creative Commons Attribution 3.0 license.