MEP 18 -- Support Milvus 2.0 C++ SDK

class MilvusClient {
 public:
    /**
     * Create a MilvusClient instance.
     *
     * @return std::shared_ptr<MilvusClient>
     */
    static std::shared_ptr<MilvusClient>
    Create();

    /**
     * Connect to Milvus server.
     *
     * @param [in] connect_param server address and port
     * @return Status operation successfully or not
     */
    virtual Status
    Connect(const ConnectParam& connect_param) = 0;

    /**
     * Break connections between client and server.
     *
     * @return Status operation successfully or not
     */
    virtual Status
    Disconnect() = 0;

    /**
     * Create a collection with schema.
     *
     * @param [in] schema schema of the collection
     * @return Status operation successfully or not
     */
    virtual Status
    CreateCollection(const CollectionSchema& schema) = 0;

    /**
     * Check existence of a collection.
     *
     * @param [in] collection_name name of the collection
     * @param [out] has true: collection exists, false: collection doesn't exist
     * @return Status operation successfully or not
     */
    virtual Status
    HasCollection(const std::string& collection_name, bool& has) = 0;

    /**
     * Drop a collection, with all its partitions, index and segments.
     *
     * @param [in] collection_name name of the collection
     * @return Status operation successfully or not
     */
    virtual Status
    DropCollection(const std::string& collection_name) = 0;

    /**
     * Load collection data into CPU memory of query node.
     * If the timeout is specified, this api will call ShowCollections() to check collection's loading state,
     * waiting until the collection completely loaded into query node.
     *
     * @param [in] collection_name name of the collection
     * @param [in] timeout timeout setting for loading, set to nullptr to return instantly
     * @return Status operation successfully or not
     */
    virtual Status
    LoadCollection(const std::string& collection_name, const TimeoutSetting* timeout) = 0;

    /**
     * Release collection data from query node.
     *
     * @param [in] collection_name name of the collection
     * @return Status operation successfully or not
     */
    virtual Status
    ReleaseCollection(const std::string& collection_name) = 0;

    /**
     * Get collection description, including its schema.
     *
     * @param [in] collection_name name of the collection
     * @param [out] collection_desc collection's description
     * @return Status operation successfully or not
     */
    virtual Status
    DescribeCollection(const std::string& collection_name, CollectionDesc& collection_desc) = 0;

    /**
     * Get collection statistics, currently only return row count.
     * If the timeout is specified, this api will call Flush() and wait all segmetns persisted into storage.
     *
     * @param [in] collection_name name of the collection
     * @param [in] timeout specify time out for sync-flush mode, set to nullptr to return instantly
     * @param [out] collection_stat statistics of the collection
     * @return Status operation successfully or not
     */
    virtual Status
    GetCollectionStatistics(const std::string& collection_name, const TimeoutSetting* timeout,
                            CollectionStat& collection_stat) = 0;

    /**
     * If the collection_names is empty, list all collections brief informations.
     * If the collection_names is specified, return the specified collection's loading process state.
     *
     * @param [in] collection_names name array of collections
     * @param [out] collections_info brief informations of the collections
     * @return Status operation successfully or not
     */
    virtual Status
    ShowCollections(const std::vector<std::string>& collection_names, CollectionsInfo& collections_info) = 0;

    /**
     * Create a partition in a collection.
     *
     * @param [in] collection_name name of the collection
     * @param [in] partition_name name of the partition
     * @return Status operation successfully or not
     */
    virtual Status
    CreatePartition(const std::string& collection_name, const std::string& partition_name) = 0;

    /**
     * Drop a partition, with its index and segments.
     *
     * @param [in] collection_name name of the collection
     * @param [in] partition_name name of the partition
     * @return Status operation successfully or not
     */
    virtual Status
    DropPartition(const std::string& collection_name, const std::string& partition_name) = 0;

    /**
     * Check existence of a partition.
     *
     * @param [in] collection_name name of the collection
     * @param [in] partition_name name of the partition
     * @param [out] has true: partition exists, false: partition doesn't exist
     * @return Status operation successfully or not
     */
    virtual Status
    HasPartition(const std::string& collection_name, const std::string& partition_name, bool& has) = 0;

    /**
     * Load specific partitions data of one collection into query nodes.
     * If the timeout is specified, this api will call ShowPartitions() to check partition's loading state,
     * waiting until the collection completely loaded into query node.
     *
     * @param [in] collection_name name of the collection
     * @param [in] partition_names name array of the partitions
     * @param [in] timeout timeout setting for loading, set to nullptr to return instantly
     * @return Status operation successfully or not
     */
    virtual Status
    LoadPartitions(const std::string& collection_name, const std::vector<std::string>& partition_names,
                   const TimeoutSetting* timeout) = 0;

    /**
     * Release specific partitions data of one collection into query nodes.
     *
     * @param [in] collection_name name of the collection
     * @param [in] partition_names name array of the partitions
     * @return Status operation successfully or not
     */
    virtual Status
    ReleasePartitions(const std::string& collection_name, const std::vector<std::string>& partition_names) = 0;

    /**
     * Get partition statistics, currently only return row count.
     * If the timeout is specified, this api will call Flush() and wait all segmetns persisted into storage.
     *
     * @param [in] collection_name name of the collection
     * @param [in] partition_name name of the partition
     * @param [in] timeout specify time out for sync-flush mode, set to nullptr to return instantly
     * @param [out] partition_stat statistics of the partition
     * @return Status operation successfully or not
     */
    virtual Status
    GetPartitionStatistics(const std::string& collection_name, const std::string& partition_name,
                           const TimeoutSetting* timeout, PartitionStat& partition_stat) = 0;

    /**
     * If the partition_names is empty, list all partitions brief informations.
     * If the partition_names is specified, return the specified partition's loading process state.
     *
     * @param [in] collection_name name of the collection
     * @param [in] partition_names name array of the partitions
     * @param [out] partitions_info brief informations of the partitions
     * @return Status operation successfully or not
     */
    virtual Status
    ShowPartitions(const std::string& collection_name, const std::vector<std::string>& partition_names,
                   PartitionsInfo& partitions_info) = 0;

	/**
     * Create an alias for a collection. Alias can be used in search or query to replace the collection name.
     * For more information: https://wiki.lfaidata.foundation/display/MIL/MEP+10+--+Support+Collection+Alias
     *
     * @param [in] collection_name name of the collection
     * @param [in] alias alias of the partitions
     * @return Status operation successfully or not
     */
    virtual Status
    CreateAlias(const std::string& collection_name, const std::string& alias) = 0;

    /**
     * Drop an alias.
     *
     * @param [in] alias alias of the partitions
     * @return Status operation successfully or not
     */
    virtual Status
    DropAlias(const std::string& alias) = 0;

    /**
     * Change an alias from a collection to another.
     *
     * @param [in] collection_name name of the collection
     * @param [in] alias alias of the partitions
     * @return Status operation successfully or not
     */
    virtual Status
    AlterAlias(const std::string& collection_name, const std::string& alias) = 0;

    /**
     * Create an index on a field. Currently only support index on vector field.
     *
     * @param [in] index_desc the index descriptions and parameters
     * @return Status operation successfully or not
     */
    virtual Status
    CreateIndex(const std::string& collection_name, const IndexDesc& index_desc) = 0;

    /**
     * Get index descriptions and parameters.
     *
     * @param [in] collection_name name of the collection
     * @param [in] field_name name of the field
     * @param [out] index_desc index descriptions and parameters
     * @return Status operation successfully or not
     */
    virtual Status
    DescribeIndex(const std::string& collection_name, const std::string& field_name, IndexDesc& index_desc) = 0;

    /**
     * Get state of an index. From the state client can know whether the index has finished or in-progress.
     *
     * @param [in] collection_name name of the collection
     * @param [in] field_name name of the field
     * @param [out] state index state of field
     * @return Status operation successfully or not
     */
    virtual Status
    GetIndexState(const std::string& collection_name, const std::string& field_name, IndexState& state) = 0;

    /**
     * Get progress of an index. From the progress client can how many rows have been indexed.
     *
     * @param [in] collection_name name of the collection
     * @param [in] field_name name of the field
     * @param [out] progress progress array of field, currently only return one index progress
     * @return Status operation successfully or not
     */
    virtual Status
    GetIndexBuildProgress(const std::string& collection_name, const std::string& field_name,
                          IndexProgress& progress) = 0;

    /**
     * Drop index of a field.
     *
     * @param [in] collection_name name of the collection
     * @param [in] field_name name of the field
     * @return Status operation successfully or not
     */
    virtual Status
    DropIndex(const std::string& collection_name, const std::string& field_name) = 0;
};