How to get an oracle price quote on devnet (agoricdev-11)

[dckc]

Once you have your solo wallet client set up with the REPL open:

Your home object has a priceAuthority property:

command[0] pa = home.priceAuthority
history[0] [Object Alleged: fake price authority]{}

Next you need the brands of the tokens in which the oracle issues quotes.
I tend to put each brand on a "kit" object for that token:

command[1] lookup('agoricNames', 'oracleBrand', 'USD').then(brand => (USD={brand}))
history[1] {"brand":[Object Alleged: USD brand]{}}
command[2] lookup('agoricNames', 'oracleBrand', 'ATOM').then(brand => (ATOM={brand}))
history[2] {"brand":[Object Alleged: ATOM brand]{}}

If we add a unit property to our token kits, we can use a mk function to abbreviate ERTP amounts:

command[4] USD.unit = ATOM.unit = 1_000_000n
history[4] 1000000n
command[7] mk = (kit, qty) => ({brand: kit.brand, value: qty * kit.unit})
history[7] [Function mk]

Now we're ready to makeQuoteNotifier for 1,000 ATOM in USD:

command[13] E(pa).makeQuoteNotifier(mk(ATOM, 1_000n), USD.brand)
history[13] [Object Alleged: QuoteNotifier]{}
command[14] qn=history[13]
history[14] [Object Alleged: QuoteNotifier]{}

And finally, as with all notifiers, we can getUpdateSince to get an update; that is: a quote:

command[15] E(qn).getUpdateSince()
history[15] {"updateCount":107,"value":{"quoteAmount":{"brand":[Object Alleged: quote brand]{},"value":[{"amountIn":{"brand":[Object Alleged: ATOM brand]{},"value":1001000n},"amountOut":{"brand":[Object Alleged: USD brand]{},"value":14225711n},"timer":[Object Alleged: timerService]{},"timestamp":1652215788n}]},"quotePayment":[Object Alleged: quote payment]{}}}

We can continue to get quotes on demand:

command[16] E(qn).getUpdateSince(107)
history[16] {"updateCount":108,"value":{"quoteAmount":{"brand":[Object Alleged: quote brand]{},"value":[{"amountIn":{"brand":[Object Alleged: ATOM brand]{},"value":1001000n},"amountOut":{"brand":[Object Alleged: USD brand]{},"value":14179753n},"timer":[Object Alleged: timerService]{},"timestamp":1652215801n}]},"quotePayment":[Object Alleged: quote payment]{}}}
command[17] E(qn).getUpdateSince(108)
history[17] {"updateCount":123,"value":{"quoteAmount":{"brand":[Object Alleged: quote brand]{},"value":[{"amountIn":{"brand":[Object Alleged: ATOM brand]{},"value":1001000n},"amountOut":{"brand":[Object Alleged: USD brand]{},"value":14014448n},"timer":[Object Alleged: timerService]{},"timestamp":1652216274n}]},"quotePayment":[Object Alleged: quote payment]{}}}

That's kind of a mouthful:

• The update has updateCount and value properties.
  • The value has quoteAmount and quotePayment properties.
    • The quoteAmount, like all ERTP amounts, has a brand and a value.
      • The value has amountIn and amountOut (as well as timer and timestamp)
        • The values of amountIn and amountOut are in the smallest denomination, 10^-6 ATOM / USD resp.

So let's make a little function to format quote amounts:

command[36] fmtQuote6 = ({value: [{amountIn, amountOut}]}) => `${(Number(amountOut.value) / Number(amountIn.value)).toFixed(3)} ${amountIn.brand} / ${amountOut.brand}`.replace(/\[object Alleged: (\w+) brand\]/g, '$1')
history[36] [Function fmtQuote6]

Now when getUpdateSince gives us all that stuff:

command[38] E(qn).getUpdateSince(123)
history[38] {"updateCount":224,"value":{"quoteAmount":{"brand":[Object Alleged: quote brand]{},"value":[{"amountIn":{"brand":[Object Alleged: ATOM brand]{},"value":1001000n},"amountOut":{"brand":[Object Alleged: USD brand]{},"value":13374841n},"timer":[Object Alleged: timerService]{},"timestamp":1652219283n}]},"quotePayment":[Object Alleged: quote payment]{}}}

we can pick out just the quoteAmount:

command[39] ({value: { quoteAmount }} = history[38]), null
history[39] null

and then format it nicely:

command[40] fmtQuote6(quoteAmount)
history[40] "13.361 ATOM / USD"

Screenshot

Governance proposal to choose the oracle operator for agoricdev-11

https://devnet.explorer.agoric.net/proposals/3

[Tartuffo]

@btulloh here ya go!

[dckc]

I neglected to split the question and the answer, but this is answered.