SymbolLoader.md

SymbolLoader

Use the SymbolLoader family of classes to feed the Kusto parser with database schemas directly from your cluster.

ServerSymbolLoader

The ServerSymbolLoader class loads symbols from a Kusto server using admin commands to request schema.

Discover databases available in a cluster

var connection = new KustoConnectionStringBuilder(...);
var loader = new ServerSymbolLoader(connection);
var names = await loader.LoadDatabaseNamesAsync();

Load database schema into a symbol

var loader = new ServerSymbolLoader(connection);
var db = await loader.LoadDatabaseAsync(dbName);

Load database schema into a GlobalState and set it as the default database

var globals = GlobalState.Default;
var loader = new ServerSymbolLoader(connection);
var globalsWithDB = await loader.AddOrUpdateDefaultDatabaseAsync(globals, dbName);
var parsed = KustoCode.ParseAndAnalyze(query, globalsWithDB);

FileSymbolLoader

The FileSymbolLoader class loads and saves symbols into a file based symbol store.

Load symbols directly from a file symbol loader (no server involved)

var loader = new FileSymbolLoader(schemaCacheDirectoryPath, defaultClusterName);
var db = await loader.LoadDatabaseAsync(dbName);

Delete all cached schema

var loader = new FileSymbolLoader(schemaCacheDirectoryPath, defaultClusterName);
loader.DeleteCache();

Delete all cached schema from a cached server symbol loader.

var loader = new CachedServerSymbolLoader(clusterConnectionString, schemaCacheDirectoryPath);
loader.FileLoader.DeleteCache();

Delete cached schema for a single cluster only

var loader = new FileSymbolLoader(schemaCacheDirectoryPath, defaultClusterName);
loader.DeleteClusterCache(clusterName);

Delete cached schema for the default cluster only

var loader = new FileSymbolLoader(schemaCacheDirectoryPath, defaultClusterName);
loader.DeleteClusterCache();

Manually store schema for database symbol into a file based schema store.

var loader = new FileSymbolLoader(schemaCacheDirectoryPath, defaultClusterName);
var databaseSymbol = ...;
await loader.SaveDatabaseAsync(databaseSymbol, clusterName);

Manually store schema for entire cluster symbol into a file based schema store.

var loader = new FileSymbolLoader(schemaCacheDirectoryPath, defaultClusterName);
var clusterSymbol = ...;
await loader.SaveClusterAsync(clusterSymbol);

Manually store schema for multiple cluster symbols into a file based schema store.

var loader = new FileSymbolLoader(schemaCacheDirectoryPath, defaultClusterName);
var clusterSymbols = new ClusterSymbol[] { ... };
await loader.SaveClustersAsync(clusterSymbols);

CachedSymbolLoader

The CachedSymbolLoader class combines both the ServerSymbolLoader and FileSymbolLoader classes togther to make a SymbolLoader that loads symbols from either a file based cache or a kusto server when not found in the cache.

Use a cached symbol loader to speed up repeated symbol loading

var connection = new KustoConnectionStringBuilder(...);
var loader = new CachedSymbolLoader(connection, schemaCacheDirectoryPath);
var db = await loader.LoadDatabaseAsync(dbName);