Initial ada connector version

Author: robkorn

connectors/ada-usd-connector/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "ada-usd-connector"
+version = "0.1.0"
+authors = ["Robert Kornacki <11645932+robkorn@users.noreply.github.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+json            = "0.12.4"
+reqwest         = { version = "0.10.7", features = ["blocking"] }
+frontend-connector-lib     = {path = "../frontend-connector-lib"}
+anyhow          = "1.0.32"
+openssl = { version = "0.10", features = ["vendored"] }

connectors/ada-usd-connector/src/main.rs

@@ -0,0 +1,44 @@
+/// This Connector obtains the lovelace per 1 USD rate and submits it
+/// to an oracle core. It reads the `oracle-config.yaml` to find the port
+/// of the oracle core (via Connector-Lib) and submits it to the POST API
+/// server on the core.
+/// Note: The value that is posted on-chain is the number
+/// of lovelaces per 1 USD, not the rate per lovelace.
+use anyhow::{anyhow, Result};
+use frontend_connector_lib::FrontendConnector;
+
+// Number of Lovelaces in a single Ada
+static LOVELACE_CONVERSION: f64 = 1000000.0;
+
+static CG_RATE_URL: &str =
+    "https://api.coingecko.com/api/v3/simple/price?ids=cardano&vs_currencies=USD";
+
+/// Get the Ada/USD price from the Lovelaces per 1 USD datapoint price
+pub fn generate_current_price(datapoint: u64) -> f64 {
+    (1.0 / datapoint as f64) * LOVELACE_CONVERSION
+}
+
+/// Acquires the price of Ada in USD from CoinGecko, convert it
+/// into Lovelaces per 1 USD, and return it.
+fn get_lovelace_usd_price() -> Result<u64> {
+    let resp = reqwest::blocking::Client::new().get(CG_RATE_URL).send()?;
+    let price_json = json::parse(&resp.text()?)?;
+    if let Some(p) = price_json["cardano"]["usd"].as_f64() {
+        let lovelace_price = (1.0 / p) * LOVELACE_CONVERSION;
+        return Ok(lovelace_price as u64);
+    } else {
+        Err(anyhow!("Failed to parse price from json."))
+    }
+}
+
+fn main() {
+    // Create the FrontendConnector
+    let connector = FrontendConnector::new_basic_connector(
+        "ADA-USD",
+        get_lovelace_usd_price,
+        generate_current_price,
+    );
+
+    // Start the FrontendConnector
+    connector.run();
+}

connectors/erg-usd-connector/src/main.rs

@@ -18,8 +18,8 @@ pub fn generate_current_price(datapoint: u64) -> f64 {
     (1.0 / datapoint as f64) * NANO_ERG_CONVERSION
 }
 
-/// Acquires the price of Ergs in USD from CoinGecko and convert it
-/// into nanoErgs per 1 USD.
+/// Acquires the price of Ergs in USD from CoinGecko, convert it
+/// into nanoErgs per 1 USD, and return it.
 fn get_nanoerg_usd_price() -> Result<u64> {
     let resp = reqwest::blocking::Client::new().get(CG_RATE_URL).send()?;
     let price_json = json::parse(&resp.text()?)?;