API Reference

This reference is auto-generated from the godoc comments in the fountain and ftkit source trees via npm run gen:api. The pages below are not hand-edited — to change their content, edit the godoc comments in the source and regenerate. See Regenerating below.

Framework

Core framework packages: the application entry point, lifecycle primitives, controller registration, and global constants.

• fountain — framework entry point and lifecycle (New(), Serving())
• runnable — AppInstance, Invoker, JobInstance lifecycle interfaces
• core — CoreController, registration, and the cross-controller observer pattern
• constants — global K-prefixed constants

Clients

Protocol client packages.

• fhttp_client — HTTP client
• fgrpc_client — gRPC client
• fgrpc_client/interceptor — gRPC client interceptors
• fgrpc_client/resolver — gRPC name resolver
• ftcp_client — TCP client
• fudp_client — UDP client
• fquic_client — QUIC client

Servers

Multi-protocol server implementations under libs/fnet.

• fnet/fhttp — HTTP (Fiber)
• fnet/fgrpc — gRPC
• fnet/ftcp — TCP
• fnet/fudp — UDP
• fnet/fquic — QUIC
• fnet/codec — message codec utilities
• fnet/endpoint — endpoint abstraction

Storage

Storage backends under libs/stored. New code should prefer fedis (see the storage migration note on the Contributing page).

• stored/fedis — Redis (current)
• stored/fongo — MongoDB
• stored/fcql — Cassandra / CQL
• stored/felastic — Elasticsearch
• stored/fbolt — BoltDB
• stored/badger — BadgerDB
• stored/s3_client — AWS S3
• stored/esdb — EventStoreDB
• stored/fgraph — Graph database
• stored/fql — SQL abstraction

Caches

In-memory and distributed cache implementations under libs/cache.

• cache — cache abstraction and unified API
• cache/redis_cache — Redis-backed cache
• cache/memcache — Memcached
• cache/memory_cache — in-process memory cache
• cache/lru_cache — LRU eviction cache
• cache/lfu_cache — LFU eviction cache
• cache/arc_cache — ARC eviction cache
• cache/slru_cache — Segmented LRU cache
• cache/buntdb — BuntDB in-memory store
• cache/file_cache — file-based cache

Brokers

Message broker integrations under libs/brokers.

• brokers — broker abstraction and message types
• brokers/fmqtt — MQTT
• brokers/pipeline/middleware — pipeline middleware (retry, throttle, circuit breaker…)
• brokers/pipeline/plugin — pipeline plugin signals
• brokers/pubsub/gochannel — in-process Go channel pub/sub
• brokers/pubsub/sync — synchronous pub/sub helper
• brokers/subscriber — subscriber helpers

Broker providers

• brokers/providers/fnat — NATS
• brokers/providers/fka — Apache Kafka
• brokers/providers/fmqp — RabbitMQ (AMQP)
• brokers/providers/fedis — Redis Streams / Pub-Sub
• brokers/providers/sse — Server-Sent Events
• brokers/providers/sns — AWS SNS
• brokers/providers/sqs — AWS SQS

Auth

Authentication packages.

• auth_token — JWT / token management
• social_auth — OAuth2 social login
• firebase_auth — Firebase Authentication

Service discovery

Service discovery backends under libs/sd.

• sd/fconsul — Consul
• sd/fetcd — etcd
• sd/fregistry — registry abstraction
• sd/k8s — Kubernetes

Observability

Logging, tracing, and metrics.

• flog — structured logging (zerolog-based)
• flog/grpc_log — gRPC log adapter
• ftracer — distributed tracing (OpenTelemetry)
• metrics — metrics abstraction
• metrics/prometheus — Prometheus exporter
• metrics/cloudwatch — AWS CloudWatch
• metrics/cloudwatch2 — AWS CloudWatch v2
• metrics/influx — InfluxDB
• metrics/influx_stats_d — InfluxDB StatsD
• metrics/dog_stats_d — DogStatsD (Datadog)
• metrics/stats_d — StatsD
• metrics/graphite — Graphite
• metrics/multi — fan-out to multiple sinks
• metrics/expvar — Go expvar
• metrics/generic — generic in-process metrics
• metrics/discard — no-op / discard

Resilience

• fsentinel — Alibaba Sentinel flow control
• resilient/backoff — retry with backoff
• resilient/circuit_breaker — circuit breaker
• resilient/locker — distributed lock
• resilient/ratelimit — rate limiting
• resilient/recaptcha — reCAPTCHA verification

Workers & tasks

Background workers, jobs, and scheduling.

• fsync — concurrency primitives (worker pool root)
• fsync/fgo — goroutine pool
• fsync/fatomic — atomic helpers
• ftasker/fjob — one-shot jobs
• ftasker/fcron — cron scheduling
• ftasker/fcroner — cron daemon

Notifications

• noti/firebase_message — Firebase Cloud Messaging (FCM)
• noti/fmail — email notifications

Crypto

• crypto — cryptography helpers (hashing, encryption, signing)

System utilities

• fcpu — CPU affinity and core utilities
• fcycle — application lifecycle hooks
• ip2geo — IP-to-geography lookup
• k8f — Kubernetes helpers
• buff — byte buffer pool

Utilities

General-purpose utilities.

• env — environment configuration helpers
• fcontext — context helpers
• ferr — error wrapping and handling
• fflag — feature flags
• validator — input validation

Base utilities

Low-level utility packages under libs/base.

• base/arr_util — slice/array utilities
• base/bool_util — boolean helpers
• base/byte_util — byte slice helpers
• base/dump — debug dumping
• base/fgo — lightweight goroutine helpers
• base/fn — functional programming helpers
• base/fson — JSON helpers
• base/goinfo — Go runtime info
• base/map_util — map utilities
• base/net_util — network utilities
• base/num_util — numeric utilities
• base/rand_util — random generation
• base/reflect_util — reflection helpers
• base/string_util — string utilities
• base/structs — struct helpers
• base/syncs — synchronization primitives
• base/sys_util — OS/system utilities
• base/time_util — time utilities

ftkit

Reference for the ftkit toolkit packages.

• ffs — filesystem helpers
• progress_bar — progress bar

Regenerating

These pages are produced by npm run gen:api. Regeneration requires the sibling fountain and ftkit repositories checked out alongside fountain-docs (their locations can be overridden with the FOUNTAIN_SRC and FTKIT_SRC environment variables), plus gomarkdoc installed:

go install github.com/princjef/gomarkdoc/cmd/gomarkdoc@latest
npm run gen:api