tail.md

Developer Tail

Julewire::Tail is a bounded in-memory destination for local inspection. It is not delivery, buffering, or audit storage.

tail = Julewire::Tail.attach!(capacity: 200)

Julewire.info("booted", service: "api")

puts tail.render(limit: 20)

Julewire.tail attaches a tail destination to the default runtime:

tail = Julewire.tail(capacity: 100)

The tail stores public formatter output after Julewire's normal processors have run. It omits hidden carry data and execution-lineage internals, and it applies core serializer bounds before records enter the ring buffer. tail.records returns frozen snapshots; tail.render returns one-line text; tail.write(io) writes that text to an IO.

Use Julewire::ConsoleFormatter with Julewire::TextEncoder for normal stdout text destinations. Tail uses the same text encoder for its rendered view.

CLI Tail

julewire tail reads JSON logs from a file or stdin and renders compact text:

julewire tail --format core log/development.jsonl

Provider gems can register their own file decoders, so mixed platform stdout can be tailed without teaching core about provider log envelopes:

platform logs -f service/my-app | julewire tail --format provider_json --raw-invalid -

Core decoders own Julewire's core JSON shape; provider gems own provider wire shapes.

julewire --version prints the core CLI version.

Parsing is strict by default. Use --skip-invalid to ignore non-JSON lines or --raw-invalid to print boot noise and platform lines unchanged while decoded Julewire records are rendered normally.

julewire transcode uses the same provider-owned decoders, then writes another registered output format. Core ships core JSON and console text; provider gems can register their own output formats:

platform logs service/my-app | julewire transcode --from provider_json --to core --raw-invalid -

Julewire::TextEncoder.new(theme: :punk) is a high-contrast local console style. Julewire.punk! configures a named runtime with that formatter/encoder pair.

julewire doctor --punk renders the doctor report as loud terminal text. Plain julewire doctor stays JSON for scripts.

Julewire.dev! configures the same console and attaches a tail in one core-only call:

tail = Julewire.dev!(tail: { capacity: 500 })

Use a custom formatter when the local view should differ from default output:

tail = Julewire::Tail.attach!(
  formatter: ->(record) { { severity: record.fetch(:severity), message: record.fetch(:message) } }
)

The tail is a normal custom destination. Julewire.health reports its size, capacity, capture count, and formatter failures under the tail destination name.

Julewire::TailSampling is separate from the developer tail. It wraps another destination and buffers records until an execution summary decides whether to keep the execution. Errors and slow executions are kept; the rest are sampled with Julewire's deterministic sampling hash. Pass decider: for a custom callable policy; it receives the summary record and key:.