The FrogNet Monitor

Run it and you are watching the pond think.

It writes nothing, owns nothing, and holds no state that outlives a keystroke. Everything on the screen came out of FrogNet Memory a moment earlier, using two HTTP calls and a name — the same calls any application of yours would make. It cannot find out which node wrote what it is showing you.

Two calls and a name
Two calls and a name

The FrogNet Monitor — video 7 of the series.

Video 7 of the series — not required to get a FrogNet running, and the best fundamental introduction to working with FrogNet Memory anyway.

§01Two calls and a name

Everything else on this site asks you to accept an architecture. This asks you to look at one program.

The Monitor has no protocol in it at all — only names, reads, and a screen. Each machine writes its own state into the memory; the Monitor is an ordinary reader of the same memory every program reads. The same record, from two viewpoints, is the whole trick — and in the video a live degraded peer is diagnosed on camera with nothing but that.

The write side — not the Monitor's

Every node publishes its own state under its own name. The Monitor never asks a machine anything; the machine already said it.

The read side — all the Monitor is

Read a value by name. Read a set by prefix. That is the complete surface — the two calls your application would make.

It is also the network's standing test. A dashboard that paints means the local proxy answered, the local daemon carried the request, the elected data host served it, and the far side's sensors were published. A column that goes blank is a layer telling you it stopped.

And it is the cheapest possible contribution: write your own reader, in any language, against two calls. If it disagrees with the Monitor, one of us has a bug worth having found. The full chapter is in the book — § 41c, The Monitor — Reading It Back →

"C did not replace assembler — it uses assembler. You lose some of that exquisite control, and you gain so much more. That is what FrogNet Memory does for you."

From the Monitor video — the best statement of the thesis in the series

Watch the series → The programming surface →