adk-action

Shared action node types for ADK-Rust graph workflows.

This crate provides the type definitions, error types, and variable interpolation utilities used by both adk-studio (visual builder) and adk-graph (runtime engine) for deterministic, non-LLM workflow operations.

Overview

Action nodes are programmatic graph nodes that perform specific operations — HTTP calls, state manipulation, conditional branching, looping, file I/O, database queries, notifications, and more. They complement LLM agent nodes in adk-graph workflows.

adk-action is the shared type layer. It contains no execution logic, no HTTP clients, no database drivers. Execution lives in adk-graph behind feature flags.

Contents

Action Node Types

Installation

[dependencies]
adk-action = "0.8.0"

Usage

Defining an action node

use adk_action::*;
use serde_json::json;

let config = ActionNodeConfig::Set(SetNodeConfig {
    standard: StandardProperties {
        id: "init_vars".into(),
        name: "Initialize Variables".into(),
        description: None,
        position: None,
        error_handling: ErrorHandling {
            mode: ErrorMode::Stop,
            retry_count: None,
            retry_delay: None,
            fallback_value: None,
        },
        tracing: Tracing { enabled: true, log_level: LogLevel::Debug },
        callbacks: Callbacks::default(),
        execution: ExecutionControl { timeout: 30000, condition: None },
        mapping: InputOutputMapping {
            input_mapping: None,
            output_key: "initResult".into(),
        },
    },
    mode: SetMode::Set,
    variables: vec![
        Variable {
            key: "greeting".into(),
            value: json!("Hello, ADK!"),
            value_type: "string".into(),
            is_secret: false,
        },
    ],
    env_vars: None,
});

// Serialize to JSON (same format as adk-studio projects)
let json = serde_json::to_string_pretty(&config).unwrap();

Variable interpolation

use adk_action::interpolate_variables;
use std::collections::HashMap;
use serde_json::json;

let mut state = HashMap::new();
state.insert("name".to_string(), json!("Alice"));
state.insert("user".to_string(), json!({"email": "alice@example.com"}));

// Simple interpolation
let result = interpolate_variables("Hello, {{name}}!", &state);
assert_eq!(result, "Hello, Alice!");

// Nested dot-notation
let email = adk_action::get_nested_value(&state, "user.email");
assert_eq!(email, Some(&json!("alice@example.com")));

JSON round-trip (adk-studio ↔ adk-graph)

use adk_action::ActionNodeConfig;

// Deserialize from adk-studio JSON
let json = r#"{"type":"set","id":"my_node","name":"Set Vars",
  "errorHandling":{"mode":"stop"},"tracing":{"enabled":true,"logLevel":"debug"},
  "callbacks":{},"execution":{"timeout":30000},
  "mapping":{"outputKey":"result"},"mode":"set","variables":[]}"#;

let config: ActionNodeConfig = serde_json::from_str(json).unwrap();

// Re-serialize produces identical JSON
let roundtrip = serde_json::to_string(&config).unwrap();
let reparsed: ActionNodeConfig = serde_json::from_str(&roundtrip).unwrap();
assert_eq!(config, reparsed);

StandardProperties

Every action node includes StandardProperties with:

• Identity: id, name, description
• Error handling: mode (stop/continue/retry/fallback), retry_count, retry_delay, fallback_value
• Tracing: enabled, log_level (none/error/info/debug)
• Callbacks: on_start, on_complete, on_error
• Execution control: timeout (ms), condition (skip when false)
• Mapping: input_mapping, output_key

Error Types

ActionError covers all action node failure modes with structured variants:

All variants implement From<ActionError> for AdkError for seamless integration with the ADK error system.

Design Principles

• Lean: Only types, errors, and interpolation. No runtime, no HTTP clients, no database drivers.
• Shared: Identical types used by adk-studio (visual builder) and adk-graph (runtime engine).
• Serialization-first: All types derive Serialize/Deserialize with camelCase field naming and skip_serializing_if for optional fields.
• Tagged union: ActionNodeConfig uses #[serde(tag = "type")] so the JSON "type" field determines the variant.

License

Apache-2.0