micro--go-micro
Asim Aslam
550033dcce
* perf: convert generated PNGs to optimized JPEGs (12MB -> 1.5MB) The landing and docs loaded 18 AI-generated PNGs at 0.5-1MB each. They're 1200x800 RGB illustrations with no transparency, so they recompress ~8x as progressive JPEG (quality 82) with no visible loss. Convert all, update every reference (.png -> .jpg), and drop the originals (including the unused hero.png). Generated images: 12.3MB -> 1.5MB. * fix(registry/etcd): re-register when a lease silently expires (#2956) The keepalive rework (long-lived KeepAlive instead of KeepAliveOnce) moved lease renewal entirely onto the keepalive goroutine; the 30s periodic Register now skips on the 'unchanged' check. The goroutine only reacted to the keepalive channel closing, so a lease that expired server-side without a prompt channel close (e.g. a partition that outlasted the 90s TTL) left the node de-registered from etcd while the cache still believed it was registered — and nothing re-registered it. That is the hidden-failure mode reported in #2956. React to a non-positive TTL keepalive response the same as a channel close: drop the cached lease/hash so the next Register performs a full re-registration. Extract the loop into keepAliveLoop and unit-test the TTL-expired, channel-closed, and healthy paths (no etcd required). --------- Co-authored-by: Claude <noreply@anthropic.com>
131 行
4.6 KiB
Markdown
131 行
4.6 KiB
Markdown
---
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layout: default
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---
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# Configuration
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<img src="/images/generated/config.jpg" alt="Configuration" style="width: 100%; border-radius: 8px; margin: 1rem 0 1.5rem;" />
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Go Micro follows a progressive configuration model so you can start with zero setup and layer in complexity only when needed.
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## Levels of Configuration
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1. Zero Config (Defaults)
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- mDNS registry, HTTP transport, in-memory broker/store
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2. Environment Variables
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- Override core components without code changes
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3. Code Options
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- Fine-grained control via functional options
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4. External Sources (Future / Plugins)
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- Configuration loaded from files, vaults, or remote services
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## Core Environment Variables
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| Component | Variable | Example | Purpose |
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|-----------|----------|---------|---------|
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| Registry | `MICRO_REGISTRY` | `MICRO_REGISTRY=consul` | Select registry implementation |
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| Registry Address | `MICRO_REGISTRY_ADDRESS` | `MICRO_REGISTRY_ADDRESS=127.0.0.1:8500` | Point to registry service |
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| Broker | `MICRO_BROKER` | `MICRO_BROKER=nats` | Select broker implementation |
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| Broker Address | `MICRO_BROKER_ADDRESS` | `MICRO_BROKER_ADDRESS=nats://localhost:4222` | Broker endpoint |
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| Transport | `MICRO_TRANSPORT` | `MICRO_TRANSPORT=nats` | Select transport implementation |
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| Transport Address | `MICRO_TRANSPORT_ADDRESS` | `MICRO_TRANSPORT_ADDRESS=nats://localhost:4222` | Transport endpoint |
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| Store | `MICRO_STORE` | `MICRO_STORE=postgres` | Select store implementation |
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| Store Database | `MICRO_STORE_DATABASE` | `MICRO_STORE_DATABASE=app` | Logical database name |
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| Store Table | `MICRO_STORE_TABLE` | `MICRO_STORE_TABLE=records` | Default table/collection |
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| Store Address | `MICRO_STORE_ADDRESS` | `MICRO_STORE_ADDRESS=postgres://user:pass@localhost:5432/app?sslmode=disable` | Connection string |
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| Server Address | `MICRO_SERVER_ADDRESS` | `MICRO_SERVER_ADDRESS=:8080` | Bind address for RPC server |
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## Example: Switching Components via Env Vars
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```bash
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# Use NATS for broker and transport, Consul for registry
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export MICRO_BROKER=nats
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export MICRO_TRANSPORT=nats
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export MICRO_REGISTRY=consul
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export MICRO_REGISTRY_ADDRESS=127.0.0.1:8500
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# Run your service
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go run main.go
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```
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No code changes required. The framework internally wires the selected implementations.
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## Equivalent Code Configuration
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```go
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service := micro.NewService(
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micro.Name("helloworld"),
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micro.Broker(nats.NewBroker()),
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micro.Transport(natstransport.NewTransport()),
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micro.Registry(consul.NewRegistry(registry.Addrs("127.0.0.1:8500"))),
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)
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service.Init()
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```
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Use env vars for deployment level overrides; use code options for explicit control or when composing advanced setups.
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## Precedence Rules
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1. Explicit code options always win
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2. If not set in code, env vars are applied
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3. If neither code nor env vars set, defaults are used
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## Discoverability Strategy
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Defaults allow local development with zero friction. As teams scale:
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- Introduce env vars for staging/production parity
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- Consolidate secrets (e.g. store passwords) using external secret managers (future guide)
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- Move to service mesh aware registry (Consul/NATS JetStream)
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## Validating Configuration
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Enable debug logging to confirm selected components:
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```bash
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MICRO_LOG_LEVEL=debug go run main.go
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```
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You will see lines like:
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```text
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Registry [consul] Initialised
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Broker [nats] Connected
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Transport [nats] Listening on nats://localhost:4222
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Store [postgres] Connected to app/records
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```
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## Patterns
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### Twelve-Factor Alignment
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Environment variables map directly to deploy-time configuration. Avoid hardcoding component choices so services remain portable.
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### Multi-Environment Setup
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Use a simple env file per environment:
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```bash
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# .env.staging
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MICRO_REGISTRY=consul
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MICRO_REGISTRY_ADDRESS=consul.staging.internal:8500
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MICRO_BROKER=nats
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MICRO_BROKER_ADDRESS=nats.staging.internal:4222
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MICRO_STORE=postgres
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MICRO_STORE_ADDRESS=postgres://staging:pass@pg.staging.internal:5432/app?sslmode=disable
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```
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Load with your process manager or container orchestrator.
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## Troubleshooting
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| Symptom | Cause | Fix |
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|---------|-------|-----|
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| Service starts with memory store unexpectedly | Env vars not exported | `env | grep MICRO_STORE` to verify |
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| Consul errors about connection refused | Wrong address/port | Check `MICRO_REGISTRY_ADDRESS` value |
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| NATS connection timeout | Server not running | Start NATS or change address |
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| Postgres SSL errors | Missing sslmode param | Append `?sslmode=disable` locally |
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## Related
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- [ADR-009: Progressive Configuration](architecture/adr-009-progressive-configuration.md)
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- [Getting Started](getting-started.html)
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- [Plugins](plugins.html)
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