api.proto

/**
 * Katib GRPC API v1beta1
 */
syntax = "proto3";

package api.v1.beta1;

/**
 * DBManager service defines APIs to manage Katib database.
 */
service DBManager {
    /** 
     * Report a log of Observations for a Trial.
     * The log consists of timestamp and value of metric.
     * Katib store every log of metrics.
     * You can see accuracy curve or other metric logs on UI.
     */
    rpc ReportObservationLog(ReportObservationLogRequest) returns (ReportObservationLogReply);

    /**
     * Get all log of Observations for a Trial.
     */
    rpc GetObservationLog(GetObservationLogRequest) returns (GetObservationLogReply);

    /**
     * Delete all log of Observations for a Trial.
     */
    rpc DeleteObservationLog(DeleteObservationLogRequest) returns (DeleteObservationLogReply);
}

/**
 * Suggestion service defines APIs to manage Katib Suggestion from HP or NAS algorithms
 */
service Suggestion {
    rpc GetSuggestions(GetSuggestionsRequest) returns (GetSuggestionsReply);
    rpc ValidateAlgorithmSettings(ValidateAlgorithmSettingsRequest) returns (ValidateAlgorithmSettingsReply);
}

/**
 * EarlyStopping service defines APIs to manage Katib Early Stopping algorithms
 */
service EarlyStopping {
    rpc GetEarlyStoppingRules(GetEarlyStoppingRulesRequest) returns (GetEarlyStoppingRulesReply);
    rpc SetTrialStatus(SetTrialStatusRequest) returns (SetTrialStatusReply);
    rpc ValidateEarlyStoppingSettings(ValidateEarlyStoppingSettingsRequest) returns (ValidateEarlyStoppingSettingsReply);
}

/**
 * Structure for a single Experiment.
 */
message Experiment {
    string name = 1; // Name for the Experiment.
    ExperimentSpec spec = 2; // Experiment specification.
}

/**
 * Specification of an Experiment. Experiment represents a single optimization run over a feasible space. 
 * Each Experiment contains a configuration describing the feasible space, as well as a set of Trials.
 * It is assumed that objective function f(x) does not change in the course of an Experiment.
 */
message ExperimentSpec {
    /** 
    * List of ParameterSpec.
    */
    message ParameterSpecs {
        repeated ParameterSpec parameters = 1;
    }
    ParameterSpecs parameter_specs = 1;
    ObjectiveSpec objective = 2; // Objective specification for the Experiment.
    AlgorithmSpec algorithm = 3; // HP or NAS algorithm specification for the Experiment.
    EarlyStoppingSpec early_stopping = 4; // Early stopping specification for the Experiment.
    int32 parallel_trial_count = 5; // How many Trials can be processed in parallel.
    int32 max_trial_count = 6; // Max completed Trials to mark Experiment as succeeded.
    NasConfig nas_config = 7; // NAS configuration for the Experiment.
}

/**
 * Config for a hyperparameter.
 * Katib will create each Hyper parameter from this config.
 */
message ParameterSpec {
    string name = 1; /// Name of the parameter.
    ParameterType parameter_type = 2; /// Type of the parameter.
    FeasibleSpace feasible_space = 3; /// FeasibleSpace for the parameter.
}

/**
 * Types of value for HyperParameter.
 */
enum ParameterType {
    UNKNOWN_TYPE = 0; /// Undefined type and not used.
    DOUBLE = 1; /// Double float type. Use "Max/Min".
    INT = 2; /// Int type. Use "Max/Min".
    DISCRETE = 3; /// Discrete number type. Use "List" as float.
    CATEGORICAL = 4; /// Categorical type. Use "List" as string.
}

/**
 * Feasible space for optimization.
 * Int and Double type use Max/Min.
 * Discrete and Categorical type use List.
 */
message FeasibleSpace {
    string max = 1; /// Max Value
    string min = 2; /// Minimum Value
    repeated string list = 3; /// List of Values.
    string step = 4; /// Step for double or int parameter
}

/**
 * Objective specification.
 */
message ObjectiveSpec {
    ObjectiveType type = 1; // Type of optimization.
    double goal = 2; // Goal of optimization, can be empty.
    string objective_metric_name = 3; // Primary metric name for the optimization.
    // List of additional metrics to record from Trial.
    // This can be empty if we only care about the objective metric.
    repeated string additional_metric_names = 4;     
}

/**
 * Direction of optimization. Minimize or Maximize.
 */
enum ObjectiveType {
    UNKNOWN = 0; /// Undefined type and not used.
    MINIMIZE = 1; /// Minimize
    MAXIMIZE = 2; /// Maximize
}

/**
 * HP or NAS algorithm specification.
 */
message AlgorithmSpec {
    string algorithm_name = 1;
    repeated AlgorithmSetting algorithm_settings = 2;
}

/**
 * HP or NAS algorithm settings.
 */
message AlgorithmSetting {
    string name = 1;
    string value = 2;
}

/**
 * Early stopping algorithm specification.
 */
message EarlyStoppingSpec {
    string algorithm_name = 1;
    repeated EarlyStoppingSetting algorithm_settings = 2;
}

/**
 * Early stopping algorithm settings.
 */
message EarlyStoppingSetting {
    string name = 1;
    string value = 2;
}

/**
 * NasConfig contains a config of NAS job
 */
message NasConfig {
    GraphConfig graph_config = 1; /// Config of DAG
    message Operations {
        repeated Operation operation = 1;
    }
    Operations operations = 2; /// List of Operation
}

/**
 * GraphConfig contains a config of DAG
 */
message GraphConfig {
    int32 num_layers = 1; /// Number of layers
    repeated int32 input_sizes = 2; /// Dimensions of input size
    repeated int32 output_sizes = 3; /// Dimensions of output size
}

/**
 * Config for operations in DAG
 */
message Operation {
    string operation_type = 1; /// Type of operation in DAG
    /** 
     * List of ParameterSpec
     */
    message ParameterSpecs {
        repeated ParameterSpec parameters = 1; 
    }
    ParameterSpecs parameter_specs = 2;
}

/**
 * Structure for a single Trial.
 */
message Trial {
    string name = 1; // Name for the Trial.
    TrialSpec spec = 2; // Trial specification.
    TrialStatus status = 3; // Trial status.
 }

/**
 * Specification of a Trial. It represents Trial's parameter assignments and objective.
 */
message TrialSpec {
    /** 
    * List of ParameterAssignment
    */
    message ParameterAssignments {
        repeated ParameterAssignment assignments = 1;
    }
    ObjectiveSpec objective = 2; // Objective specification for the Trial.
    ParameterAssignments parameter_assignments = 3; // List of assignments generated for the Trial.
}

message ParameterAssignment {
    string name = 1;
    string value = 2;
}

/**
 * Current Trial status. It contains Trial's latest condition, start time, completion time, observation.
 */
message TrialStatus {
    // Trial can be in one of 6 conditions.
    // TODO (andreyvelich): Remove unused conditions.
    enum TrialConditionType {
        CREATED = 0;
        RUNNING = 1;
        SUCCEEDED = 2;
        KILLED = 3;
        FAILED = 4;
        EARLYSTOPPED = 5;
        UNKNOWN = 6;
    }
    string start_time = 1; // Trial start time in RFC3339 format
    string completion_time = 2; // Trial completion time in RFC3339 format
    TrialConditionType condition = 3; // Trial current condition. It is equal to the latest Trial CR condition.
    Observation observation = 4; // The best Trial observation in logs.
}

message Observation {
    repeated Metric metrics = 1;
}

message Metric {
    string name = 1;
    string value = 2;
}

message ReportObservationLogRequest {
    string trial_name = 1;
    ObservationLog observation_log = 2;
}

message ReportObservationLogReply {
}

message ObservationLog {
    repeated MetricLog metric_logs = 1;
}

message MetricLog {
    string time_stamp = 1; /// RFC3339 format
    Metric metric = 2;
}

message GetObservationLogRequest {
    string trial_name = 1;
    string metric_name = 2;
    string start_time = 3; ///The start of the time range. RFC3339 format
    string end_time = 4; ///The end of the time range. RFC3339 format
}

message GetObservationLogReply {
    ObservationLog observation_log = 1;
}

message DeleteObservationLogRequest {
    string trial_name = 1;
}

message DeleteObservationLogReply {
}

message GetSuggestionsRequest {
    Experiment experiment = 1;
    repeated Trial trials = 2; // All completed trials owned by the experiment.
    // Use current_request_number instead. This API will be removed in Katib 0.14.
    // The number of Suggestions requested at one time.
    int32 request_number = 3 [deprecated=true];
    // The number of Suggestions requested at one time.
    // When you set 3 to current_request_number, you get three Suggestions at one time.
    int32 current_request_number = 4; 
    int32 total_request_number = 5; // The number of Suggestions requested till now.
}

message GetSuggestionsReply {
    message ParameterAssignments {
        repeated ParameterAssignment assignments = 1;
    }
    repeated ParameterAssignments parameter_assignments = 1;
    AlgorithmSpec algorithm = 2;
    repeated EarlyStoppingRule early_stopping_rules = 3;
}

message ValidateAlgorithmSettingsRequest {
    Experiment experiment = 1;
}

/**
 * Return INVALID_ARGUMENT Error if Algorithm Settings are not Valid
 */
message ValidateAlgorithmSettingsReply {
}

message GetEarlyStoppingRulesRequest {
    Experiment experiment = 1;
    repeated Trial trials = 2; 
    string db_manager_address = 3;
}

message GetEarlyStoppingRulesReply {
    repeated EarlyStoppingRule early_stopping_rules = 1;
}

/**
 * EarlyStoppingRule represents single early stopping rule.
 */
message EarlyStoppingRule {
    string name = 1; // Name of the rule. Usually, metric name.
    string value = 2; // Value of the metric.
    ComparisonType comparison = 3; // Correlation between name and value, one of equal, less or greater
    // Defines quantity of intermediate results that should be received before applying the rule.
    // If start step is empty, rule is applied from the first recorded metric.
    int32 start_step = 4; 
}

message ValidateEarlyStoppingSettingsRequest {
    EarlyStoppingSpec early_stopping = 1;
}

/**
 * Return INVALID_ARGUMENT Error if Early Stopping Settings are not Valid
 */
message ValidateEarlyStoppingSettingsReply {
}

enum ComparisonType {
    UNKNOWN_COMPARISON = 0; // Unknown comparison, not used
    EQUAL = 1; // Equal comparison, e.g. accuracy = 0.7
    LESS = 2; // Less comparison, e.g. accuracy < 0.7
    GREATER = 3; // Greater comparison, e.g. accuracy > 0.7
}

message SetTrialStatusRequest {
    string trial_name = 1;
}

message SetTrialStatusReply {
}