soroban_sdk/testutils/
cost_estimate.rs

1use soroban_env_host::{fees::FeeConfiguration, FeeEstimate, InvocationResources};
2
3use crate::{testutils::budget::Budget, Env};
4
5pub struct CostEstimate {
6    env: Env,
7}
8
9impl CostEstimate {
10    pub(crate) fn new(env: Env) -> Self {
11        Self { env }
12    }
13
14    /// Returns the resources metered during the last top level contract
15    /// invocation.    
16    /// Take the return value with a grain of salt. The returned resources mostly
17    /// correspond only to the operations that have happened during the host
18    /// invocation, i.e. this won't try to simulate the work that happens in
19    /// production scenarios (e.g. certain XDR rountrips). This also doesn't try
20    /// to model resources related to the transaction size.
21    ///
22    /// The returned value is as useful as the preceding setup, e.g. if a test
23    /// contract is used instead of a Wasm contract, all the costs related to
24    /// VM instantiation and execution, as well as Wasm reads/rent bumps will be
25    /// missed.    
26    pub fn resources(&self) -> InvocationResources {
27        if let Some(res) = self.env.host().get_last_invocation_resources() {
28            res
29        } else {
30            panic!("Invocation cost estimate is not available. Make sure invocation cost metering is enabled in the EnvTestConfig and this is called after an invocation.")
31        }
32    }
33
34    /// Estimates the fee for the last invocation's resources, i.e. the
35    /// resources returned by `resources()`.
36    ///
37    /// The fees are computed using the snapshot of the Stellar Pubnet fees made
38    /// on 2024-12-11.
39    ///
40    /// Take the return value with a grain of salt as both the resource estimate
41    /// and the fee rates may be imprecise.
42    ///
43    /// The returned value is as useful as the preceding setup, e.g. if a test
44    /// contract is used instead of a Wasm contract, all the costs related to
45    /// VM instantiation and execution, as well as Wasm reads/rent bumps will be
46    /// missed.    
47    pub fn fee(&self) -> FeeEstimate {
48        // This is a snapshot of the fees as of 2024-12-11.
49        let pubnet_fee_config = FeeConfiguration {
50            fee_per_instruction_increment: 25,
51            fee_per_read_entry: 6250,
52            fee_per_write_entry: 10000,
53            fee_per_read_1kb: 1786,
54            // This is a bit higher than the current network fee, it's an
55            // overestimate for the sake of providing a bit more conservative
56            // results in case if the state grows.
57            fee_per_write_1kb: 12000,
58            fee_per_historical_1kb: 16235,
59            fee_per_contract_event_1kb: 10000,
60            fee_per_transaction_size_1kb: 1624,
61        };
62        let pubnet_persistent_rent_rate_denominator = 2103;
63        let pubnet_temp_rent_rate_denominator = 4206;
64
65        self.resources().estimate_fees(
66            &pubnet_fee_config,
67            pubnet_persistent_rent_rate_denominator,
68            pubnet_temp_rent_rate_denominator,
69        )
70    }
71
72    /// Returns the budget object that provides the detailed CPU and memory
73    /// metering information recorded thus far.
74    ///
75    /// The budget metering resets before every top-level contract level
76    /// invocation.
77    ///
78    /// budget() may also be used to adjust the CPU and memory limits via the
79    /// `reset_` methods.
80    ///
81    /// Note, that unlike `resources()`/`fee()` this will always return some
82    /// value. If there was no contract call, then the resulting value will
83    /// correspond to metering any environment setup that has been made thus
84    /// far.
85    pub fn budget(&self) -> Budget {
86        Budget::new(self.env.host().budget_cloned())
87    }
88}
soroban_sdk/testutils/cost_estimate.rs

soroban_sdk/testutils/
cost_estimate.rs
