Read settings from config

Instead of hard-coding the sample files, read settings from config.

.gitignore

@@ -1,3 +1,5 @@
+/config.toml
+
 /target/
 **/*.rs.bk
 *.gnucash.*LCK

Cargo.toml

@@ -4,11 +4,12 @@ version = "0.1.0"
 authors = ["David Cain <[email protected]>"]
 
 [dependencies]
-quick-xml = "0.13.1"
-rust_decimal = ">= 0.11.2"
-rusqlite = "0.16.0"
 chrono = "0.4.6"
 csv = "1"
+num = "0.2.0"
+quick-xml = "0.13.1"
+rusqlite = "0.16.0"
+rust_decimal = ">= 0.11.2"
 serde = "1"
 serde_derive = "1"
-num = "0.2.0"
+toml = "0.5"

README.md

@@ -60,8 +60,8 @@ Contribute the following amounts:
 
 ### Sample GnuCash accounting records
 
-`example.sqlite3` and `example.gnucash` are included sample files that may be
-opened with [GnuCash 3][gnucash]. The transactions, security prices, and
+In `example/` are two (identical) sample files in XML and sqlite3 format. Each
+may be opened with [GnuCash 3][gnucash]. The transactions, security prices, and
 account balances contained within are the basis of rebalancing logic:
 
 ![GnuCash user interface for included sample files][img-gnucash-interface]

example_config.toml

@@ -0,0 +1,6 @@
+[user]
+birthday = '1972-07-12'
+
+[gnucash]
+path_to_book = 'my_books.gnucash'
+file_format = 'sqlite3'

src/config.rs

@@ -0,0 +1,102 @@
+extern crate chrono;
+extern crate serde_derive;
+
+use serde_derive::Deserialize;
+
+use self::chrono::NaiveDate;
+use std::fs;
+
+#[derive(Deserialize)]
+struct User {
+    birthday: String, // YYYY-MM-DD
+}
+
+impl User {
+    fn birthday(&self) -> NaiveDate {
+        NaiveDate::parse_from_str(&self.birthday, "%Y-%m-%d").unwrap()
+    }
+}
+
+#[derive(Deserialize)]
+pub struct GnuCash {
+    pub path_to_book: String,
+    pub file_format: String,
+}
+
+#[derive(Deserialize)]
+pub struct Config {
+    user: User,
+    pub gnucash: GnuCash,
+}
+
+impl Config {
+    /// Return default settings for use with the sample data
+    pub fn default() -> Config {
+        Config {
+            user: User {
+                birthday: String::from("1985-01-01"),
+            },
+            gnucash: GnuCash {
+                path_to_book: String::from("example.sqlite3"),
+                file_format: String::from("sqlite3"),
+            },
+        }
+    }
+
+    pub fn user_birthday(&self) -> NaiveDate {
+        self.user.birthday()
+    }
+
+    /// Return a Config from file, or default settings if not present
+    ///
+    /// See `example_config.toml` for a sample configuration:
+    ///
+    /// ```toml
+    /// [user]
+    /// birthday = '1971-06-14'
+    ///
+    /// [gnucash]
+    /// path_to_book = '/path/to/database.gnucash'
+    /// file_format = 'sqlite3'
+    /// ```
+    pub fn from_file(path: &str) -> Config {
+        let config_toml = match fs::read_to_string(path) {
+            Ok(file) => file,
+            Err(_) => {
+                // Silently fall back to the default
+                return Config::default();
+            }
+        };
+
+        toml::from_str(&config_toml).unwrap()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_parses_birthday() {
+        let user = User {
+            birthday: String::from("1962-12-31"),
+        };
+        assert_eq!(user.birthday(), NaiveDate::from_ymd(1962, 12, 31));
+    }
+
+    #[test]
+    fn test_parse_from_toml() {
+        let conf = Config::from_file("example_config.toml");
+        assert_eq!(conf.user_birthday(), NaiveDate::from_ymd(1972, 7, 12));
+        assert_eq!(&conf.gnucash.path_to_book, "my_books.gnucash");
+        assert_eq!(&conf.gnucash.file_format, "sqlite3");
+    }
+
+    #[test]
+    fn test_fallback_to_default_settings() {
+        let conf = Config::from_file("/tmp/definitely_does_not_exist.toml");
+        assert_eq!(&conf.user.birthday, "1985-01-01");
+        assert_eq!(&conf.gnucash.path_to_book, "example.sqlite3");
+        assert_eq!(&conf.gnucash.file_format, "sqlite3");
+    }
+}

src/gnucash.rs

@@ -15,6 +15,7 @@ use std::io::BufReader;
 use std::str::FromStr;
 
 use assets;
+use config::Config;
 use rebalance::{AssetAllocation, Portfolio};
 
 static GNUCASH_DT_FORMAT: &str = "%Y-%m-%d %H:%M:%S %z";
@@ -671,6 +672,17 @@ impl Book {
         }
     }
 
+    pub fn from_config(conf: &Config) -> Book {
+        let path = &conf.gnucash.path_to_book;
+        if conf.gnucash.file_format == "sqlite3" {
+            return Book::from_sqlite_file(path);
+        } else if conf.gnucash.file_format == "xml" {
+            return Book::from_xml_file(path);
+        } else {
+            panic!("Other file formats not supported at this time");
+        }
+    }
+
     pub fn from_sqlite_file(filename: &str) -> Book {
         let conn = Connection::open(filename).expect("Could not open file");
         Book::from_sqlite(&conn)

src/main.rs

@@ -12,10 +12,12 @@ use std::io;
 mod allocation;
 mod assets;
 mod compounding;
+mod config;
 mod gnucash;
 mod rebalance;
 mod stats;
 
+use config::Config;
 use gnucash::Book;
 
 fn get_contribution() -> Decimal {
@@ -67,12 +69,11 @@ fn summarize_retirement_prospects(birthday: NaiveDate, portfolio_total: Decimal,
 }
 
 fn main() {
-    let sqlite_file = "example.sqlite3";
-    let book = Book::from_sqlite_file(sqlite_file);
-    //let book = Book::from_xml_file("example.gnucash");
+    let conf = Config::from_file("config.toml");
+    let book = Book::from_config(&conf);
 
     // Identify our ideal allocations (percentages by asset class, summing to 100%)
-    let birthday = NaiveDate::from_ymd(1985, 1, 1);
+    let birthday = conf.user_birthday();
     let bond_allocation = allocation::bond_allocation(birthday, 120);
     let ideal_allocations = allocation::core_four(bond_allocation);
 
@@ -84,15 +85,17 @@ fn main() {
 
     summarize_retirement_prospects(birthday, portfolio.current_value(), 0.07);
 
-    let sql_stats = stats::Stats::new(sqlite_file);
-    let after_tax = sql_stats.after_tax_income().unwrap();
-    let charity = sql_stats.charitable_giving().unwrap();
-    println!("After-tax income: ${:.0}", after_tax);
-    println!(
-        "Charitable giving: ${:.0} ({:.0}% of after-tax income)",
-        charity,
-        (charity / after_tax) * Decimal::from(100)
-    );
+    if conf.gnucash.file_format == "sqlite3" {
+        let sql_stats = stats::Stats::new(&conf.gnucash.path_to_book);
+        let after_tax = sql_stats.after_tax_income().unwrap();
+        let charity = sql_stats.charitable_giving().unwrap();
+        println!("After-tax income: ${:.0}", after_tax);
+        println!(
+            "Charitable giving: ${:.0} ({:.0}% of after-tax income)",
+            charity,
+            (charity / after_tax) * Decimal::from(100)
+        );
+    }
 
     let contribution = get_contribution();