extract the index abstraction out of the index-scheduler in its own module

index/src/error.rs

@@ -0,0 +1,48 @@
+use std::error::Error;
+
+use meilisearch_types::error::{Code, ErrorCode};
+use meilisearch_types::internal_error;
+use serde_json::Value;
+
+pub type Result<T> = std::result::Result<T, IndexError>;
+
+#[derive(Debug, thiserror::Error)]
+pub enum IndexError {
+    #[error("An internal error has occurred. `{0}`.")]
+    Internal(Box<dyn Error + Send + Sync + 'static>),
+    #[error("Document `{0}` not found.")]
+    DocumentNotFound(String),
+    #[error("{0}")]
+    Facet(#[from] FacetError),
+    #[error("{0}")]
+    Milli(#[from] milli::Error),
+}
+
+internal_error!(
+    IndexError: std::io::Error,
+    milli::heed::Error,
+    fst::Error,
+    serde_json::Error,
+    file_store::Error,
+    milli::documents::Error
+);
+
+impl From<milli::UserError> for IndexError {
+    fn from(error: milli::UserError) -> IndexError {
+        IndexError::Milli(error.into())
+    }
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum FacetError {
+    #[error("Invalid syntax for the filter parameter: `expected {}, found: {1}`.", .0.join(", "))]
+    InvalidExpression(&'static [&'static str], Value),
+}
+
+impl ErrorCode for FacetError {
+    fn error_code(&self) -> Code {
+        match self {
+            FacetError::InvalidExpression(_, _) => Code::Filter,
+        }
+    }
+}