FallbackProvider

Documentation for eth_defi.provider.fallback.FallbackProvider Python class.

class FallbackProvider

Fault-tolerance for JSON-RPC requests with multiple providers.

Fall back to the next provider on the list if a JSON-RPC request fails. Contains build-in retry logic in round-robin manner. We will also recover from situations when we suspect the node does not have the block data we are asking yet (but should have shorty).

See also

• eth_defi.middlware.exception_retry_middleware()

• eth_defi.middlware.ProbablyNodeHasNoBlock()

Note

FallbackProvider does not call any middlewares installed on the providers themselves.

Attributes summary

call_endpoint_uri	Return the active node URI where call JSON-RPCs go.
ccip_read_max_redirects
endpoint_uri	Return the active node URI endpoint.
global_ccip_read_enabled
is_async
middlewares
currently_active_provider	Currently active provider
api_retry_counts	provider number-> api method name -> retry counts dict

Methods summary

__init__(providers[, strategy, ...])	param providers
decode_rpc_response(raw_response)
encode_rpc_request(method, params)
get_active_provider()	Get currently active provider.
get_total_api_call_counts()	Get API call coubst across all providers
has_multiple_providers()	Have we configured multiple providers
is_connected()
make_request(method, params)	Make a request.
request_func(w3, outer_middlewares)	@param outer_middlewares is an iterable of middlewares,
switch_provider()	Switch to next available provider.

__init__(providers, strategy=FallbackStrategy.cycle_on_error, retryable_exceptions=(<class 'requests.exceptions.ConnectionError'>, <class 'requests.exceptions.HTTPError'>, <class 'requests.exceptions.Timeout'>, <class 'requests.exceptions.TooManyRedirects'>, <class 'web3.exceptions.BlockNotFound'>, <class 'requests.exceptions.ChunkedEncodingError'>), retryable_status_codes=(429, 500, 502, 503, 504), retryable_rpc_error_codes=(-32603, -32003, -32043, -32005, -32701), sleep=5.0, backoff=1.6, retries=6, state_missing_switch_over_delay=12.0, switchover_noisiness=30)

Parameters

• providers (List[eth_defi.provider.named.BaseNamedProvider | web3.providers.rpc.HTTPProvider]) – List of provider we cycle through.

• strategy –

  What is the strategy to deal with errors.

  Currently on cycling supported.

• retryable_exceptions – List of exceptions we can retry.

• retryable_status_codes – List of HTTP status codes we can retry.

• retryable_rpc_error_codes – List of GoEthereum error codes we can retry.

• sleep (float) – Seconds between retries.

• backoff (float) – Multiplier to increase sleep.

• retries (int) – How many retries we attempt before giving up.

• switchover_noisiness – How loud we are about switchover issues.

• state_missing_switch_over_delay (float) –

  If we encounter state missing condition at node, what is the minimum time (seconds) we wait before trying to switch to next node.

  See code comments for details.

currently_active_provider

Currently active provider

api_retry_counts

provider number-> api method name -> retry counts dict

property endpoint_uri

Return the active node URI endpoint.

For HTTPProvider compatibility.

has_multiple_providers()

Have we configured multiple providers

Return type

bool

switch_provider()

Switch to next available provider.

get_active_provider()

Get currently active provider.

If this provider fails, we are automatically recycled to the next one.

Return type

eth_defi.provider.named.BaseNamedProvider | web3.providers.rpc.HTTPProvider

get_total_api_call_counts()

Get API call coubst across all providers

Return type

Dict[str, int]

make_request(method, params)

Make a request.

• By default use the current active provider

• If there are errors try cycle through providers and sleep between cycles until one provider works

Parameters

• method (web3.types.RPCEndpoint) –

• params (Any) –

Return type

web3.types.RPCResponse