Code and resources for a talk about Continuous Deployment for Gophercon AU

This is a small monorepo with a naive implementation of some HTTP APIs, and some build tooling.

For the purposes of the talk, there are also 3 Pull Requests open for discussion.

The jafflr is an imaginary machine which assembles and cooks toasted sandwiches.

It attaches onto a chilly bin ('Chilly bin' is NZ English parlance - aka Esky, in Australian).

There are 2 services, jafflr and the chillybin. Crucially, jafflr depends on chillybin.

Some of these endpoints use the wrong verb (GET instead of POST) - this has been left as "change needed":

• chillybin:

• /pick?name=cheese&quantity=1 - pick stock from chillybin
• / - show current stock
• /restock - restock
• /health - health check

• jafflr:

• /toastie?i=cheese&i=vegemite - make a toastie

• this invokes chillybin

• / retrieves status (toasting/available)
• /health - health check

• Table-driven integration tests; fixtures, assertions, chaining together calls:

• Using httptest - example provided

• Managing database definitions with ‘migrations’:

• go-migrate. See chillybin
• With mongodb this can be as simple as "EnsureIndex()":w

• Bundling resources with your app (Docker or go-bindata):

• docker in this case

• Mitigating risk of changes:

• Feature Flags implemented via ENV or db
  • 3 steps:
    1. Release something cross-compatible.
    2. Switch client over to the new API
    3. Delete old endpoint (for 3rd parties this gets more complicated)
• Versioning your APIs
  1. Could be a path /v2/
  2. Could be version headers
  3. GraphQL supports deprecated fields
  4. gRPC, Twirp [Protocol Buffers] support deprecations and field renaming

• Zero-downtime deploys:

• HTTP - graceful restart. See jafflr
• healthchecks

• Metrics and alerting
• Tooling for your build system:

• Containerising build steps
• Deployment and confirmation (ECS/K8S)
• go list -deps for granular version checking. See last_commit.sh