Firebase Remote Config

Read a parameter from your Firebase Remote Config server template - the classic dynamic-config use case.

Install

go get github.com/xavidop/mamori/providers/firebase-rc

import _ "github.com/xavidop/mamori/providers/firebase-rc"

Using the ref

A firebase-rc:// ref points at one parameter in your project’s server Remote Config template.

firebase-rc://<parameter-key>[#json-key]

Examples

• firebase-rc://welcome_banner returns the server-side value of the welcome_banner parameter.
• firebase-rc://max_items returns the max_items parameter - pair it with an int field.
• firebase-rc://feature_flags#new_ui treats the feature_flags parameter as JSON and returns its new_ui field.

type Config struct {
	Banner   string `source:"firebase-rc://welcome_banner"`
	MaxItems int    `source:"firebase-rc://max_items"`
}

The provider reads the current server template (the one used by the Admin SDK and server workloads) and returns the named parameter’s default value. A missing parameter, or one configured to use the in-app default (no server value), resolves to not-found, so default: / optional:"true" applies. Value.Version is the template’s version number, which is template-wide - it changes whenever any parameter is published, so mamori may occasionally re-apply an unchanged value (harmless).

Watch

The server template has no push channel, so mamori polls (WithPollInterval + jitter).

Configuration

import rcprov "github.com/xavidop/mamori/providers/firebase-rc"

mamori.WithProvider(rcprov.New(rcprov.WithProjectID("my-project")))

Authentication uses Application Default Credentials (a service account via GOOGLE_APPLICATION_CREDENTIALS, or workload identity). Verified with an in-memory fake; live behavior is covered by //go:build integration tests.

Close() is idempotent and terminal: after it returns, every Resolve reports errors.Is(err, mamori.ErrUnavailable) locally, without contacting the Remote Config API. On the default path (Application Default Credentials, no WithHTTPClient) it releases nothing: the default client wraps an OAuth2 transport that implements no idle-connection-release method of its own, so there is no method Close could call that would release only its connections. A client injected with WithHTTPClient is never closed or invalidated, only its idle connections are returned to the pool, and only when that client’s Transport is non-nil.

Error classification

A non-200 response from the Remote Config REST API is classified by HTTP status:

A missing parameter is a separate case: it is detected after a successful (200) fetch by looking the key up in the decoded template, and maps to not-found, not to one of the statuses above.

Verified by unit tests (direct classification, plus a real httptest 403 response driven through Resolve) and the conformance kit against an in-memory fake; live behavior is covered by //go:build integration tests.