Remove use of anyhow and replace with thiserror, other markups (#7)

* Use thiserror

* use scopes over explicit use of drop

* update syntax

* remove std::fmt::Debug

* qualify thiserror

azure-kusto-ingest/Cargo.toml

@@ -13,11 +13,11 @@ azure_storage = "0.17"
 azure_storage_blobs = "0.17"
 azure_storage_queues = "0.17"
 
-anyhow = "1"
 chrono = { version = "0.4", default-features = false, features = ["serde"] }
 rand = "0.8"
 serde = { version = "1", features = ["serde_derive"] }
 serde_json = "1"
+thiserror = "1"
 tokio = { version = "1", features = ["full"] }
 tracing = { version = "0.1", default-features = false, features = ["std"] }
 url = "2"

azure-kusto-ingest/examples/ingest_from_blob.rs

@@ -1,6 +1,5 @@
 use std::env;
 
-use anyhow::Result;
 use azure_kusto_data::prelude::{ConnectionString, KustoClient, KustoClientOptions};
 use azure_kusto_ingest::data_format::DataFormat;
 use azure_kusto_ingest::descriptors::{BlobAuth, BlobDescriptor};
@@ -16,7 +15,7 @@ use azure_kusto_ingest::queued_ingest::QueuedIngestClient;
 /// - Permissions for Kusto to access storage
 ///     https://learn.microsoft.com/en-us/azure/data-explorer/ingest-data-managed-identity
 #[tokio::main]
-async fn main() -> Result<()> {
+async fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
     let cluster_ingest_uri = env::var("KUSTO_INGEST_URI").expect("Must define KUSTO_INGEST_URI");
     let user_mi_object_id =
         env::var("KUSTO_USER_MI_OBJECT_ID").expect("Must define KUSTO_USER_MI_OBJECT_ID");
@@ -54,7 +53,9 @@ async fn main() -> Result<()> {
     let blob_descriptor = BlobDescriptor::new(blob_uri, blob_size, None)
         .with_blob_auth(BlobAuth::SystemAssignedManagedIdentity);
 
-    queued_ingest_client
+    let _ = queued_ingest_client
         .ingest_from_blob(blob_descriptor, ingestion_properties)
-        .await
+        .await?;
+
+    Ok(())
 }

azure-kusto-ingest/src/error.rs

@@ -0,0 +1,20 @@
+//! Defines [Error] for representing failures in various operations.
+
+/// Error type for kusto ingestion operations.
+#[derive(thiserror::Error, Debug)]
+pub enum Error {
+    /// Error raised when failing to obtain ingestion resources.
+    #[error("Error obtaining ingestion resources: {0}")]
+    ResourceManagerError(#[from] super::resource_manager::ResourceManagerError),
+
+    /// Error relating to (de-)serialization of JSON data
+    #[error("Error in JSON serialization/deserialization: {0}")]
+    JsonError(#[from] serde_json::Error),
+
+    /// Error occurring within core azure crates
+    #[error("Error in azure-core: {0}")]
+    AzureError(#[from] azure_core::error::Error),
+}
+
+/// Result type for kusto ingest operations.
+pub type Result<T> = std::result::Result<T, Error>;

azure-kusto-ingest/src/lib.rs

@@ -1,6 +1,7 @@
 pub mod client_options;
 pub mod data_format;
 pub mod descriptors;
+pub mod error;
 pub(crate) mod ingestion_blob_info;
 pub mod ingestion_properties;
 pub mod queued_ingest;

azure-kusto-ingest/src/queued_ingest.rs

@@ -1,11 +1,8 @@
 use std::sync::Arc;
 
-use anyhow::Result;
+use crate::error::Result;
 use azure_core::base64;
 use azure_kusto_data::prelude::KustoClient;
-use rand::rngs::StdRng;
-use rand::seq::SliceRandom;
-use rand::SeedableRng;
 use tracing::debug;
 
 use crate::client_options::QueuedIngestClientOptions;
@@ -47,8 +44,8 @@ impl QueuedIngestClient {
         blob_descriptor: BlobDescriptor,
         ingestion_properties: IngestionProperties,
     ) -> Result<()> {
-        let ingestion_queues = self.resource_manager.ingestion_queues().await?;
-        debug!("ingestion queues: {:#?}", ingestion_queues);
+        let queue_client = self.resource_manager.ingestion_queue().await?;
+        debug!("ingestion queues: {:#?}", queue_client);
 
         let auth_context = self.resource_manager.authorization_context().await?;
         debug!("auth_context: {:#?}\n", auth_context);
@@ -57,14 +54,7 @@ impl QueuedIngestClient {
             QueuedIngestionMessage::new(&blob_descriptor, &ingestion_properties, auth_context);
         debug!("message: {:#?}\n", message);
 
-        // Pick a random queue from the queue clients returned by the resource manager
-        let mut rng: StdRng = SeedableRng::from_entropy();
-        let queue_client = ingestion_queues
-            .choose(&mut rng)
-            .ok_or(anyhow::anyhow!("Failed to pick a random queue"))?;
-        debug!("randomly seeded queue_client: {:#?}\n", queue_client);
-
-        let message = serde_json::to_string(&message).unwrap();
+        let message = serde_json::to_string(&message)?;
         debug!("message as string: {}\n", message);
 
         // Base64 encode the ingestion message

azure-kusto-ingest/src/resource_manager.rs

@@ -6,7 +6,6 @@ pub mod ingest_client_resources;
 pub mod resource_uri;
 pub mod utils;
 
-use anyhow::Result;
 use azure_kusto_data::prelude::KustoClient;
 
 use azure_storage_queues::QueueClient;
@@ -18,8 +17,24 @@ use self::{
     ingest_client_resources::IngestClientResources,
 };
 
+use rand::{rngs::StdRng, seq::SliceRandom, SeedableRng};
+
 pub const RESOURCE_REFRESH_PERIOD: Duration = Duration::from_secs(60 * 60);
 
+#[derive(Debug, thiserror::Error)]
+pub enum ResourceManagerError {
+    #[error("Failed to obtain ingestion resources: {0}")]
+    IngestClientResourcesError(#[from] ingest_client_resources::IngestionResourceError),
+
+    #[error("Failed to obtain authorization token: {0}")]
+    AuthorizationContextError(#[from] authorization_context::KustoIdentityTokenError),
+
+    #[error("Failed to select a resource - no resources found")]
+    NoResourcesFound,
+}
+
+type Result<T> = std::result::Result<T, ResourceManagerError>;
+
 /// ResourceManager is a struct that keeps track of all the resources required for ingestion using the queued flavour
 pub struct ResourceManager {
     ingest_client_resources: Arc<IngestClientResources>,
@@ -39,12 +54,62 @@ impl ResourceManager {
     }
 
     /// Returns the latest [QueueClient]s ready for posting ingestion messages to
-    pub async fn ingestion_queues(&self) -> Result<Vec<QueueClient>> {
+    async fn ingestion_queues(&self) -> Result<Vec<QueueClient>> {
         Ok(self.ingest_client_resources.get().await?.ingestion_queues)
     }
 
+    /// Returns a [QueueClient] to ingest to.
+    /// This is a random selection from the list of ingestion queues
+    pub async fn ingestion_queue(&self) -> Result<QueueClient> {
+        let ingestion_queues = self.ingestion_queues().await?;
+        let selected_queue = select_random_resource(ingestion_queues)?;
+        Ok(selected_queue.clone())
+    }
+
     /// Returns the latest [KustoIdentityToken] to be added as an authorization context to ingestion messages
     pub async fn authorization_context(&self) -> Result<KustoIdentityToken> {
-        self.authorization_context.get().await
+        self.authorization_context
+            .get()
+            .await
+            .map_err(ResourceManagerError::AuthorizationContextError)
+    }
+}
+/// Selects a random resource from the given list of resources
+fn select_random_resource<T: Clone>(resources: Vec<T>) -> Result<T> {
+    let mut rng: StdRng = SeedableRng::from_entropy();
+    resources
+        .choose(&mut rng)
+        .ok_or(ResourceManagerError::NoResourcesFound)
+        .cloned()
+}
+
+#[cfg(test)]
+mod select_random_resource_tests {
+    use super::*;
+
+    #[test]
+    fn single_resource() {
+        const VALUE: i32 = 1;
+        let resources = vec![VALUE];
+        let selected_resource = select_random_resource(resources).unwrap();
+        assert!(selected_resource == VALUE)
+    }
+
+    #[test]
+    fn multiple_resources() {
+        let resources = vec![1, 2, 3, 4, 5];
+        let selected_resource = select_random_resource(resources.clone()).unwrap();
+        assert!(resources.contains(&selected_resource));
+    }
+
+    #[test]
+    fn no_resources() {
+        let resources: Vec<i32> = vec![];
+        let selected_resource = select_random_resource(resources);
+        assert!(selected_resource.is_err());
+        assert!(matches!(
+            selected_resource.unwrap_err(),
+            ResourceManagerError::NoResourcesFound
+        ))
     }
 }

azure-kusto-ingest/src/resource_manager/authorization_context.rs

@@ -1,7 +1,7 @@
 use std::sync::Arc;
 
-use anyhow::Result;
 use azure_kusto_data::prelude::KustoClient;
+use serde_json::Value;
 use tokio::sync::RwLock;
 
 use super::cache::{Cached, ThreadSafeCachedValue};
@@ -10,6 +10,30 @@ use super::RESOURCE_REFRESH_PERIOD;
 
 pub(crate) type KustoIdentityToken = String;
 
+const AUTHORIZATION_CONTEXT: &str = "AuthorizationContext";
+
+#[derive(thiserror::Error, Debug)]
+pub enum KustoIdentityTokenError {
+    #[error("Kusto expected 1 table in results, found {0}")]
+    ExpectedOneTable(usize),
+
+    #[error("Kusto expected 1 row in table, found {0}")]
+    ExpectedOneRow(usize),
+
+    #[error("Column {0} not found in table")]
+    ColumnNotFound(String),
+
+    #[error("Invalid JSON response from Kusto: {0:?}")]
+    InvalidJSONResponse(Value),
+
+    #[error("Token is empty")]
+    EmptyToken,
+
+    #[error(transparent)]
+    KustoError(#[from] azure_kusto_data::error::Error),
+}
+
+type Result<T> = std::result::Result<T, KustoIdentityTokenError>;
 /// Logic to obtain a Kusto identity token from the management endpoint. This auth token is a temporary token
 #[derive(Debug, Clone)]
 pub(crate) struct AuthorizationContext {
@@ -38,54 +62,54 @@ impl AuthorizationContext {
         let table = match &results.tables[..] {
             [a] => a,
             _ => {
-                return Err(anyhow::anyhow!(
-                    "Kusto Expected 1 table in results, found {}",
-                    results.tables.len()
+                return Err(KustoIdentityTokenError::ExpectedOneTable(
+                    results.tables.len(),
                 ))
             }
         };
 
         // Check that a column in this table actually exists called `AuthorizationContext`
-        let index = get_column_index(table, "AuthorizationContext")?;
+        let index = get_column_index(table, AUTHORIZATION_CONTEXT).ok_or(
+            KustoIdentityTokenError::ColumnNotFound(AUTHORIZATION_CONTEXT.into()),
+        )?;
 
         // Check that there is only 1 row in the table, and that the value in the first row at the given index is not empty
         let token = match &table.rows[..] {
-            [row] => row.get(index).ok_or(anyhow::anyhow!(
-                "Kusto response did not contain a value in the first row at position {}",
-                index
-            ))?,
-            _ => {
-                return Err(anyhow::anyhow!(
-                    "Kusto expected 1 row in results, found {}",
-                    table.rows.len()
-                ))
-            }
+            [row] => row
+                .get(index)
+                .ok_or(KustoIdentityTokenError::ColumnNotFound(
+                    AUTHORIZATION_CONTEXT.into(),
+                ))?,
+            _ => return Err(KustoIdentityTokenError::ExpectedOneRow(table.rows.len())),
         };
 
         // Convert the JSON string into a Rust string
-        let token = token.as_str().ok_or(anyhow::anyhow!(
-            "Kusto response did not contain a string value: {:?}",
-            token
-        ))?;
+        let token = token
+            .as_str()
+            .ok_or(KustoIdentityTokenError::InvalidJSONResponse(
+                token.to_owned(),
+            ))?;
 
         if token.chars().all(char::is_whitespace) {
-            return Err(anyhow::anyhow!("Kusto identity token is empty"));
+            return Err(KustoIdentityTokenError::EmptyToken);
         }
 
         Ok(token.to_string())
     }
 
     /// Fetches the latest Kusto identity token, either retrieving from cache if valid, or by executing a KQL query
     pub(crate) async fn get(&self) -> Result<KustoIdentityToken> {
-        // Attempt to get the token from the cache
-        let token_cache = self.token_cache.read().await;
-        if !token_cache.is_expired() {
-            if let Some(token) = token_cache.get() {
-                return Ok(token.clone());
+        // first, try to get the resources from the cache by obtaining a read lock
+        {
+            let token_cache = self.token_cache.read().await;
+            if !token_cache.is_expired() {
+                if let Some(token) = token_cache.get() {
+                    return Ok(token.clone());
+                }
             }
         }
-        // Drop the read lock and get a write lock to refresh the token
-        drop(token_cache);
+
+        // obtain a write lock to refresh the kusto response
         let mut token_cache = self.token_cache.write().await;
 
         // Again attempt to return from cache, check is done in case another thread