Allow getting consumer group information

include/cppkafka/exceptions.h

@@ -74,6 +74,30 @@ public:
     InvalidConfigOptionType(const std::string& config_name, const std::string& type);
 };
 
+/** 
+ * Indicates something that was being looked up failed to be found
+ */
+class CPPKAFKA_API ElementNotFound : public Exception {
+public:
+    ElementNotFound(const std::string& element_type, const std::string& name);
+};
+
+/** 
+ * Indicates something that was incorrectly parsed
+ */
+class CPPKAFKA_API ParseException : public Exception {
+public:
+    ParseException(const std::string& message);
+};
+
+/** 
+ * Indicates something had an unexpected versiom
+ */
+class CPPKAFKA_API UnexpectedVersion : public Exception {
+public:
+    UnexpectedVersion(uint32_t version);
+};
+
 /**
  * A generic rdkafka handle error
  */

include/cppkafka/group_information.h

@@ -0,0 +1,141 @@
+#ifndef CPPKAFKA_GROUP_INFORMATION_H
+#define CPPKAFKA_GROUP_INFORMATION_H
+
+#include <vector>
+#include <cstdint>
+#include "macros.h"
+#include "metadata.h"
+#include "error.h"
+#include "topic_partition_list.h"
+
+namespace cppkafka {
+
+/**
+ * \brief Parses the member assignment information
+ *
+ * This class parses the data in GroupMemberInformation::get_member_assignment.
+ */
+class CPPKAFKA_API MemberAssignmentInformation {
+public:
+    /**
+     * Constructs an instance
+     */
+    MemberAssignmentInformation(const std::vector<uint8_t>& data);
+
+    /**
+     * Gets the version
+     */
+    uint16_t get_version() const;
+
+    /**
+     * Gets the topic/partition assignment
+     */
+    const TopicPartitionList& get_topic_partitions() const;
+private:
+    uint16_t version_;
+    TopicPartitionList topic_partitions_;
+};
+
+/**
+ * \brief Represents the information about a specific consumer group member
+ */
+class CPPKAFKA_API GroupMemberInformation {
+public:
+    /**
+     * Constructs an instance using the provided information
+     *
+     * \param info The information pointer
+     */
+    GroupMemberInformation(const rd_kafka_group_member_info& info);
+
+    /**
+     * Gets the member id
+     */
+    const std::string& get_member_id() const;
+
+    /**
+     * Gets the client id
+     */
+    const std::string& get_client_id() const;
+
+    /**
+     * Gets the client host
+     */
+    const std::string& get_client_host() const;
+
+    /**
+     * Gets the member metadata
+     */
+    const std::vector<uint8_t>& get_member_metadata() const;
+
+    /**
+     * Gets the member assignment
+     */
+    const std::vector<uint8_t>& get_member_assignment() const;
+private:
+    std::string member_id_;
+    std::string client_id_;
+    std::string client_host_;
+    std::vector<uint8_t> member_metadata_;
+    std::vector<uint8_t> member_assignment_;
+};
+
+/**
+ * \brief Represents the information about a specific consumer group
+ */
+class CPPKAFKA_API GroupInformation {
+public:
+    /**
+     * Constructs an instance using the provided information.
+     *
+     * \param info The information pointer
+     */
+    GroupInformation(const rd_kafka_group_info& info);
+
+    /**
+     * Gets the broker metadata
+     */
+    const BrokerMetadata& get_broker() const;
+
+    /**
+     * Gets the group name
+     */
+    const std::string& get_name() const;
+
+    /**
+     * Gets the broker-originated error
+     */
+    Error get_error() const;
+
+    /**
+     * Gets the group state
+     */
+    const std::string& get_state() const;
+
+    /**
+     * Gets the group protocol type
+     */
+    const std::string& get_protocol_type() const;
+
+    /**
+     * Gets the group protocol
+     */
+    const std::string& get_protocol() const;
+
+    /**
+     * Gets the group members
+     */
+    const std::vector<GroupMemberInformation>& get_members() const;
+private:
+    BrokerMetadata broker_;
+    std::string name_;
+    Error error_;
+    std::string state_;
+    std::string protocol_type_;
+    std::string protocol_;
+    std::vector<GroupMemberInformation> members_;
+};
+
+} // cppkafka
+
+#endif // CPPKAFKA_GROUP_INFORMATION_H

include/cppkafka/kafka_handle_base.h

@@ -50,6 +50,7 @@ namespace cppkafka {
 class Topic;
 class Metadata;
 class TopicMetadata;
+class GroupInformation;
 
 /**
  * Base class for kafka consumer/producer
@@ -155,6 +156,18 @@ public:
      */
     TopicMetadata get_metadata(const Topic& topic) const;
 
+    /**
+     * Gets the consumer group information
+     *
+     * \param name The name of the consumer group to look up
+     */
+    GroupInformation get_consumer_group(const std::string& name);
+
+    /**
+     * Gets all consumer groups
+     */
+    std::vector<GroupInformation> get_consumer_groups();
+
     /**
      * \brief Gets topic/partition offsets based on timestamps
      *
@@ -201,6 +214,7 @@ private:
 
     Topic get_topic(const std::string& name, rd_kafka_topic_conf_t* conf);
     Metadata get_metadata(bool all_topics, rd_kafka_topic_t* topic_ptr) const;
+    std::vector<GroupInformation> fetch_consumer_groups(const char* name);
     void save_topic_config(const std::string& topic_name, TopicConfiguration config);
 
     HandlePtr handle_;

include/cppkafka/topic_partition.h

@@ -117,6 +117,16 @@ public:
      */
     bool operator<(const TopicPartition& rhs) const;
 
+    /**
+     * Compare the (topic, partition) for equality
+     */
+    bool operator==(const TopicPartition& rhs) const;
+
+    /**
+     * Compare the (topic, partition) for in-equality
+     */
+    bool operator!=(const TopicPartition& rhs) const;
+
     /**
      * Print to a stream
      */