Error Handling

Retry, fallback, and circuit breaker patterns.

3 modules

Module	Description
Circuit Breaker	Protect against cascading failures with circuit breaker pattern
Fallback	Provide fallback value when operation fails
Retry	Wrap operations with configurable retry logic

Modules

Circuit Breaker

error.circuit_breaker

Protect against cascading failures with circuit breaker pattern

Parameters:

Name	Type	Required	Default	Description
action	object	Yes	-	The action to protect with circuit breaker
circuit_id	string	Yes	-	The action to protect with circuit breaker
failure_threshold	number	No	5	Unique identifier for this circuit (for state tracking)
failure_window_ms	number	No	60000	Time window for counting failures
recovery_timeout_ms	number	No	30000	Time before attempting recovery (half-open state)
success_threshold	number	No	3	Successful requests needed in half-open to close circuit
fallback	object	No	-	Alternative action when circuit is open
fallback_value	any	No	-	Alternative action when circuit is open
track_errors	array	No	[]	Static value to return when circuit is open

Output:

Field	Type	Description
__event__	string	Only count these error codes toward threshold (empty = all)
result	any	Event for routing (success/circuit_open/fallback)
circuit_state	string	Result from action or fallback
failure_count	number	Current state of circuit (closed/open/half_open)
last_failure_time	string	Current failure count in window
circuit_opened_at	string	Timestamp of last failure

Example: Example

action: {"module": "http.post", "params": {"url": "https://api.example.com/submit"}}
circuit_id: example-api
failure_threshold: 5
failure_window_ms: 60000
recovery_timeout_ms: 30000

Example: Example

action: {"module": "http.get", "params": {"url": "https://api.example.com/data"}}
circuit_id: data-api
failure_threshold: 3
fallback: {"module": "cache.get", "params": {"key": "data_cache"}}

Example: Example

action: {"module": "database.query", "params": {"query": "SELECT * FROM users"}}
circuit_id: database
failure_threshold: 3
fallback_value: {"users": [], "from_cache": false}

Fallback

error.fallback

Provide fallback value when operation fails

Parameters:

Name	Type	Required	Default	Description
operation	object	No	-	The primary operation to attempt
fallback_value	any	No	-	The primary operation to attempt
fallback_operation	object	No	-	Static value to return on failure
fallback_on	array	No	[]	Alternative operation to execute on failure
include_error_info	boolean	No	True	Error codes that trigger fallback (empty = all errors)
log_fallback	boolean	No	True	Include original error information in output

Output:

Field	Type	Description
result	any	Log when fallback is used
used_fallback	boolean	Result from primary operation or fallback
source	string	Whether fallback was used
original_error	object	Source of result (primary/fallback_value/fallback_operation)

Example: Example

operation: {"module": "http.get", "params": {"url": "https://api.example.com/items"}}
fallback_value: []

Example: Example

operation: {"module": "http.get", "params": {"url": "https://api.example.com/config"}}
fallback_operation: {"module": "cache.get", "params": {"key": "config_cache"}}

Example: Example

operation: {"module": "api.call", "params": {"endpoint": "/data"}}
fallback_value: {"status": "unavailable"}
fallback_on: ["NETWORK_ERROR", "TIMEOUT_ERROR"]

Retry

error.retry

Wrap operations with configurable retry logic

Parameters:

Name	Type	Required	Default	Description
operation	object	Yes	-	The operation to retry (module ID and params)
max_retries	number	No	3	The operation to retry (module ID and params)
initial_delay_ms	number	No	1000	Maximum number of retry attempts
max_delay_ms	number	No	30000	Initial delay before first retry
backoff_multiplier	number	No	2.0	Multiplier for exponential backoff (e.g., 2 doubles delay each retry)
jitter	boolean	No	True	Add random jitter to delay to prevent thundering herd
retry_on	array	No	[]	Add random jitter to delay to prevent thundering herd
timeout_per_attempt_ms	number	No	0	List of error codes to retry on (empty = retry all)

Output:

Field	Type	Description
__event__	string	Timeout for each attempt (0 for no timeout)
result	any	Event for routing (success/exhausted)
attempts	number	Event for routing (success/exhausted)
total_delay_ms	number	Result from successful attempt
errors	array	Number of attempts made

Example: Example

operation: {"module": "http.get", "params": {"url": "https://api.example.com/data"}}
max_retries: 3

Example: Example

operation: {"module": "database.query", "params": {"query": "SELECT * FROM users"}}
max_retries: 5
initial_delay_ms: 2000
backoff_multiplier: 2.0
jitter: true

Example: Example

operation: {"module": "api.call", "params": {"endpoint": "/submit"}}
max_retries: 3
retry_on: ["NETWORK_ERROR", "TIMEOUT_ERROR", "SERVICE_UNAVAILABLE"]