Add sled migration utility.

src/bin/migrate_sled.rs

@@ -0,0 +1,37 @@
+use tenebrous_dicebot::db::sqlite::{Database as SqliteDatabase, Variables};
+use tenebrous_dicebot::db::Database;
+use tenebrous_dicebot::error::BotError;
+
+#[tokio::main]
+async fn main() -> Result<(), BotError> {
+    let sled_path = std::env::args()
+        .skip(1)
+        .next()
+        .expect("Need a path to a Sled database as an arument.");
+
+    let sqlite_path = std::env::args()
+        .skip(2)
+        .next()
+        .expect("Need a path to an sqlite database as an arument.");
+
+    let db = Database::new(&sled_path)?;
+
+    let all_variables = db.variables.get_all_variables()?;
+
+    let sql_db = SqliteDatabase::new(&sqlite_path).await?;
+
+    for var in all_variables {
+        if let ((username, room_id, variable_name), value) = var {
+            println!(
+                "Migrating {}::{}::{} = {} to sql",
+                username, room_id, variable_name, value
+            );
+
+            sql_db
+                .set_user_variable(&username, &room_id, &variable_name, value)
+                .await;
+        }
+    }
+
+    Ok(())
+}

src/db.rs

@@ -19,7 +19,7 @@ pub mod variables;
 #[derive(Clone)]
 pub struct Database {
     db: Db,
-    pub(crate) variables: Variables,
+    pub variables: Variables,
     pub(crate) migrations: Migrations,
     pub(crate) rooms: Rooms,
     pub(crate) state: DbState,

src/db/errors.rs

@@ -26,6 +26,9 @@ pub enum DataError {
     #[error("expected i32, but i32 schema was violated")]
     I32SchemaViolation,
 
+    #[error("parse error")]
+    ParseError(#[from] std::num::ParseIntError),
+
     #[error("unexpected or corruptd data bytes")]
     InvalidValue,
 

src/db/sqlite/mod.rs

@@ -43,7 +43,7 @@ pub(crate) trait Rooms {
 // TODO move this up to the top once we delete sled. Traits will be the
 // main API, then we can have different impls for different DBs.
 #[async_trait]
-pub(crate) trait Variables {
+pub trait Variables {
     async fn get_user_variables(
         &self,
         user: &str,

src/db/variables.rs

@@ -10,6 +10,8 @@ use std::str;
 use zerocopy::byteorder::I32;
 use zerocopy::AsBytes;
 
+use super::errors;
+
 pub(super) mod migrations;
 
 #[derive(Clone)]
@@ -67,6 +69,9 @@ fn alter_room_variable_count(
     Ok(new_count)
 }
 
+/// Room ID, Username, Variable Name
+pub type AllVariablesKey = (String, String, String);
+
 impl Variables {
     pub(in crate::db) fn new(db: &sled::Db) -> Result<Variables, sled::Error> {
         Ok(Variables {
@@ -75,6 +80,40 @@ impl Variables {
         })
     }
 
+    pub fn get_all_variables(&self) -> Result<HashMap<AllVariablesKey, i32>, DataError> {
+        use std::convert::TryFrom;
+        let variables: Result<Vec<(AllVariablesKey, i32)>, DataError> = self
+            .room_user_variables
+            .scan_prefix("")
+            .map(|entry| match entry {
+                Ok((key, raw_value)) => {
+                    let keys: Vec<_> = key
+                        .split(|&b| b == 0xfe || b == 0xff)
+                        .map(|b| str::from_utf8(b))
+                        .collect();
+
+                    if let &[Ok(room_id), Ok(username), Ok(variable_name), ..] = keys.as_slice() {
+                        Ok((
+                            (
+                                room_id.to_owned(),
+                                username.to_owned(),
+                                variable_name.to_owned(),
+                            ),
+                            convert_i32(&raw_value)?,
+                        ))
+                    } else {
+                        Err(errors::DataError::InvalidValue)
+                    }
+                }
+                Err(e) => Err(e.into()),
+            })
+            .collect();
+
+        // Convert tuples to hash map with collect(), inferred via
+        // return type.
+        variables.map(|entries| entries.into_iter().collect())
+    }
+
     pub fn get_user_variables(
         &self,
         key: &UserAndRoom<'_>,