add tests for posthog feature flags

This commit is contained in:
Sam Rose 2024-08-07 16:59:33 +01:00
parent edb3b685b5
commit a9b4d0017f
No known key found for this signature in database
2 changed files with 135 additions and 46 deletions

View File

@ -1,14 +1,15 @@
import env from "../environment"
import * as context from "../context"
import { cloneDeep } from "lodash"
import { PostHog } from "posthog-node"
import { PostHog, PostHogOptions } from "posthog-node"
import { IdentityType } from "@budibase/types"
let posthog: PostHog | undefined
export function init() {
export function init(opts?: PostHogOptions) {
if (env.POSTHOG_TOKEN) {
posthog = new PostHog(env.POSTHOG_TOKEN, {
host: "https://us.i.posthog.com",
...opts,
})
}
}
@ -18,6 +19,14 @@ abstract class Flag<T> {
return new BooleanFlag(defaultValue)
}
static string(defaultValue: string): Flag<string> {
return new StringFlag(defaultValue)
}
static number(defaultValue: number): Flag<number> {
return new NumberFlag(defaultValue)
}
protected constructor(public defaultValue: T) {}
abstract parse(value: any): T
@ -37,6 +46,32 @@ class BooleanFlag extends Flag<boolean> {
}
}
class StringFlag extends Flag<string> {
parse(value: any) {
if (typeof value === "string") {
return value
}
throw new Error(`could not parse value "${value}" as string`)
}
}
class NumberFlag extends Flag<number> {
parse(value: any) {
if (typeof value === "number") {
return value
}
if (typeof value === "string") {
const parsed = parseFloat(value)
if (!isNaN(parsed)) {
return parsed
}
}
throw new Error(`could not parse value "${value}" as number`)
}
}
// This is the primary source of truth for feature flags. If you want to add a
// new flag, add it here and use the `fetch` and `get` functions to access it.
// All of the machinery in this file is to make sure that flags have their
@ -46,6 +81,10 @@ const FLAGS = {
GOOGLE_SHEETS: Flag.boolean(false),
USER_GROUPS: Flag.boolean(false),
ONBOARDING_TOUR: Flag.boolean(false),
_TEST_BOOLEAN: Flag.boolean(false),
_TEST_STRING: Flag.string("default value"),
_TEST_NUMBER: Flag.number(0),
}
const DEFAULTS = Object.keys(FLAGS).reduce((acc, key) => {
@ -107,6 +146,7 @@ export async function fetch(): Promise<Flags> {
throw new Error(`Feature: ${feature} is not a boolean`)
}
// @ts-ignore
flags[feature] = value
}
}
@ -114,7 +154,7 @@ export async function fetch(): Promise<Flags> {
const identity = context.getIdentity()
if (posthog && identity?.type === IdentityType.USER) {
const posthogFlags = await posthog.getAllFlagsAndPayloads(identity._id)
for (const [name, value] of Object.entries(posthogFlags)) {
for (const [name, value] of Object.entries(posthogFlags.featureFlags)) {
const key = name as keyof typeof FLAGS
const flag = FLAGS[key]
if (!flag) {
@ -124,8 +164,11 @@ export async function fetch(): Promise<Flags> {
continue
}
const payload = posthogFlags.featureFlagPayloads?.[name]
try {
flags[key] = flag.parse(value)
// @ts-ignore
flags[key] = flag.parse(payload || value)
} catch (err) {
// We don't want an invalid PostHog flag to break the app, so we just
// log it and continue.

View File

@ -2,6 +2,7 @@ import { IdentityContext, IdentityType } from "@budibase/types"
import { defaultFlags, fetch, get, Flags, init } from "../"
import { context } from "../.."
import { setEnv, withEnv } from "../../environment"
import nodeFetch from "node-fetch"
import nock from "nock"
describe("feature flags", () => {
@ -14,23 +15,23 @@ describe("feature flags", () => {
it.each<TestCase>([
{
tenant: "tenant1",
flags: "tenant1:ONBOARDING_TOUR",
expected: { ONBOARDING_TOUR: true },
flags: "tenant1:_TEST_BOOLEAN",
expected: { _TEST_BOOLEAN: true },
},
{
tenant: "tenant1",
flags: "tenant1:!ONBOARDING_TOUR",
expected: { ONBOARDING_TOUR: false },
flags: "tenant1:!_TEST_BOOLEAN",
expected: { _TEST_BOOLEAN: false },
},
{
tenant: "tenant1",
flags: "*:ONBOARDING_TOUR",
expected: { ONBOARDING_TOUR: true },
flags: "*:_TEST_BOOLEAN",
expected: { _TEST_BOOLEAN: true },
},
{
tenant: "tenant1",
flags: "tenant2:ONBOARDING_TOUR",
expected: { ONBOARDING_TOUR: false },
flags: "tenant2:_TEST_BOOLEAN",
expected: { _TEST_BOOLEAN: false },
},
{
tenant: "tenant1",
@ -62,7 +63,7 @@ describe("feature flags", () => {
it.each<FailedTestCase>([
{
tenant: "tenant1",
flags: "tenant1:ONBOARDING_TOUR,tenant1:FOO",
flags: "tenant1:_TEST_BOOLEAN,tenant1:FOO",
expected: "Feature: FOO is not an allowed option",
},
])(
@ -75,43 +76,88 @@ describe("feature flags", () => {
)
)
// describe("posthog", () => {
// const identity: IdentityContext = {
// _id: "us_1234",
// tenantId: "budibase",
// type: IdentityType.USER,
// email: "test@example.com",
// firstName: "Test",
// lastName: "User",
// }
describe("posthog", () => {
const identity: IdentityContext = {
_id: "us_1234",
tenantId: "budibase",
type: IdentityType.USER,
email: "test@example.com",
firstName: "Test",
lastName: "User",
}
// let cleanup: () => void
let cleanup: () => void
// beforeAll(() => {
// cleanup = setEnv({ POSTHOG_TOKEN: "test" })
// init()
// })
// afterAll(() => {
// cleanup()
// })
// beforeEach(() => {
// nock.cleanAll()
// })
// it("should be able to read flags from posthog", () =>
// context.doInIdentityContext(identity, async () => {
// nock("https://app.posthog.com")
// .get("/api/feature_flags/tenant/budibase")
// .reply(200, {
// flags: {
// "budibase:onboardingTour": true,
// },
// })
// const flags = await fetch()
// expect(flags.ONBOARDING_TOUR).toBe(true)
// }))
// })
beforeAll(() => {
cleanup = setEnv({ POSTHOG_TOKEN: "test" })
})
afterAll(() => {
cleanup()
})
beforeEach(() => {
nock.cleanAll()
// We need to pass in node-fetch here otherwise nock won't get used
// because posthog-node uses axios under the hood.
init({ fetch: nodeFetch })
})
function mockFlags(flags: {
featureFlags?: Record<string, boolean>
featureFlagPayloads?: Record<string, any>
}) {
nock("https://us.i.posthog.com")
.post("/decide/?v=3", body => {
return body.token === "test" && body.distinct_id === "us_1234"
})
.reply(200, flags)
}
it("should be able to read flags from posthog", async () => {
mockFlags({
featureFlags: {
_TEST_BOOLEAN: true,
},
})
await context.doInIdentityContext(identity, async () => {
const flags = await fetch()
expect(flags._TEST_BOOLEAN).toBe(true)
})
})
it("should be able to read flags from posthog with payloads", async () => {
mockFlags({
featureFlags: {
_TEST_STRING: true,
},
featureFlagPayloads: {
_TEST_STRING: "test payload",
},
})
await context.doInIdentityContext(identity, async () => {
const flags = await fetch()
expect(flags._TEST_STRING).toBe("test payload")
})
})
it("should be able to read flags from posthog with numbers", async () => {
mockFlags({
featureFlags: {
_TEST_NUMBER: true,
},
featureFlagPayloads: {
_TEST_NUMBER: 123,
},
})
await context.doInIdentityContext(identity, async () => {
const flags = await fetch()
expect(flags._TEST_NUMBER).toBe(123)
})
})
})
})