Add storage behind a trait

Reviewed-on: https://git.deuxfleurs.fr/Deuxfleurs/aerogramme/pulls/32

1 files changed, 179 insertions, 0 deletions

diff --git a/src/storage/mod.rs b/src/storage/mod.rs
new file mode 100644
index 0000000..1f86f71
--- /dev/null
+++ b/src/storage/mod.rs
@@ -0,0 +1,179 @@
+/*
+ *
+ * This abstraction goal is to leverage all the semantic of Garage K2V+S3,
+ * to be as tailored as possible to it ; it aims to be a zero-cost abstraction
+ * compared to when we where directly using the K2V+S3 client.
+ *
+ * My idea: we can encapsulate the causality token
+ * into the object system so it is not exposed.
+ */
+
+pub mod garage;
+pub mod in_memory;
+
+use async_trait::async_trait;
+use std::collections::HashMap;
+use std::hash::Hash;
+use std::sync::Arc;
+
+#[derive(Debug, Clone)]
+pub enum Alternative {
+    Tombstone,
+    Value(Vec<u8>),
+}
+type ConcurrentValues = Vec<Alternative>;
+
+#[derive(Debug, Clone)]
+pub enum StorageError {
+    NotFound,
+    Internal,
+}
+impl std::fmt::Display for StorageError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str("Storage Error: ")?;
+        match self {
+            Self::NotFound => f.write_str("Item not found"),
+            Self::Internal => f.write_str("An internal error occured"),
+        }
+    }
+}
+impl std::error::Error for StorageError {}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct RowUid {
+    pub shard: String,
+    pub sort: String,
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct RowRef {
+    pub uid: RowUid,
+    pub causality: Option<String>,
+}
+impl std::fmt::Display for RowRef {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "RowRef({}, {}, {:?})",
+            self.uid.shard, self.uid.sort, self.causality
+        )
+    }
+}
+
+impl RowRef {
+    pub fn new(shard: &str, sort: &str) -> Self {
+        Self {
+            uid: RowUid {
+                shard: shard.to_string(),
+                sort: sort.to_string(),
+            },
+            causality: None,
+        }
+    }
+    pub fn with_causality(mut self, causality: String) -> Self {
+        self.causality = Some(causality);
+        self
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct RowVal {
+    pub row_ref: RowRef,
+    pub value: ConcurrentValues,
+}
+
+impl RowVal {
+    pub fn new(row_ref: RowRef, value: Vec<u8>) -> Self {
+        Self {
+            row_ref,
+            value: vec![Alternative::Value(value)],
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct BlobRef(pub String);
+impl std::fmt::Display for BlobRef {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "BlobRef({})", self.0)
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct BlobVal {
+    pub blob_ref: BlobRef,
+    pub meta: HashMap<String, String>,
+    pub value: Vec<u8>,
+}
+impl BlobVal {
+    pub fn new(blob_ref: BlobRef, value: Vec<u8>) -> Self {
+        Self {
+            blob_ref,
+            value,
+            meta: HashMap::new(),
+        }
+    }
+
+    pub fn with_meta(mut self, k: String, v: String) -> Self {
+        self.meta.insert(k, v);
+        self
+    }
+}
+
+#[derive(Debug)]
+pub enum Selector<'a> {
+    Range {
+        shard: &'a str,
+        sort_begin: &'a str,
+        sort_end: &'a str,
+    },
+    List(Vec<RowRef>), // list of (shard_key, sort_key)
+    #[allow(dead_code)]
+    Prefix {
+        shard: &'a str,
+        sort_prefix: &'a str,
+    },
+    Single(&'a RowRef),
+}
+impl<'a> std::fmt::Display for Selector<'a> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::Range {
+                shard,
+                sort_begin,
+                sort_end,
+            } => write!(f, "Range({}, [{}, {}[)", shard, sort_begin, sort_end),
+            Self::List(list) => write!(f, "List({:?})", list),
+            Self::Prefix { shard, sort_prefix } => write!(f, "Prefix({}, {})", shard, sort_prefix),
+            Self::Single(row_ref) => write!(f, "Single({})", row_ref),
+        }
+    }
+}
+
+#[async_trait]
+pub trait IStore {
+    async fn row_fetch<'a>(&self, select: &Selector<'a>) -> Result<Vec<RowVal>, StorageError>;
+    async fn row_rm<'a>(&self, select: &Selector<'a>) -> Result<(), StorageError>;
+    async fn row_insert(&self, values: Vec<RowVal>) -> Result<(), StorageError>;
+    async fn row_poll(&self, value: &RowRef) -> Result<RowVal, StorageError>;
+
+    async fn blob_fetch(&self, blob_ref: &BlobRef) -> Result<BlobVal, StorageError>;
+    async fn blob_insert(&self, blob_val: BlobVal) -> Result<(), StorageError>;
+    async fn blob_copy(&self, src: &BlobRef, dst: &BlobRef) -> Result<(), StorageError>;
+    async fn blob_list(&self, prefix: &str) -> Result<Vec<BlobRef>, StorageError>;
+    async fn blob_rm(&self, blob_ref: &BlobRef) -> Result<(), StorageError>;
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct UnicityBuffer(Vec<u8>);
+
+#[async_trait]
+pub trait IBuilder: std::fmt::Debug {
+    async fn build(&self) -> Result<Store, StorageError>;
+
+    /// Returns an opaque buffer that uniquely identifies this builder
+    fn unique(&self) -> UnicityBuffer;
+}
+
+pub type Builder = Arc<dyn IBuilder + Send + Sync>;
+pub type Store = Box<dyn IStore + Send + Sync>;