[SOLVED] Rusoto crate example doesn't compile

help
1

I am trying to use rusoto (https://rusoto.org) to access AWS S3 bucket, and started with this example https://rusoto.github.io/rusoto/rusoto_core/struct.EnvironmentProvider.html, but I get compilation errors.

The things that puzzles me is that the compiler says two opposing things at the same time :

help: the following trait is implemented but not in scope, perhaps add a `use` for it:
   |
4  | use futures::future::Future;
   |

and

warning: unused import: `futures::future::Future`
 --> src/main.rs:4:5
  |
4 | use futures::future::Future;
  |     ^^^^^^^^^^^^^^^^^^^^^^^
  |

Steps to reproduce:

  1. code for Cargo.toml
[package]
name = "rusoto_s3_test"
version = "0.1.0"

[dependencies]
rusoto_core = "0.32.0"
rusoto_credential = "0.11.0"
futures = "0.2.1"
  1. code for src/main.rs:
extern crate futures;
extern crate rusoto_credential;

use futures::future::Future;
use rusoto_credential::{EnvironmentProvider, ProvideAwsCredentials};
use std::env;

fn main() {
    env::set_var("AWS_ACCESS_KEY_ID", "ANTN35UAENTS5UIAEATD");
    env::set_var("AWS_SECRET_ACCESS_KEY", "TtnuieannGt2rGuie2t8Tt7urarg5nauedRndrur");
    env::set_var("AWS_SESSION_TOKEN", "DfnGs8Td4rT8r4srxAg6Td4rT8r4srxAg6GtkTir");

    let creds = EnvironmentProvider.credentials().wait().unwrap();

    assert_eq!(creds.aws_access_key_id(), "ANTN35UAENTS5UIAEATD");
    assert_eq!(creds.aws_secret_access_key(), "TtnuieannGt2rGuie2t8Tt7urarg5nauedRndrur");
    assert_eq!(creds.token(), &Some("DfnGs8Td4rT8r4srxAg6Td4rT8r4srxAg6GtkTir".to_string()));
    assert!(creds.expires_at().is_none()); // doesn't expire

    env::set_var("AWS_CREDENTIAL_EXPIRATION", "2018-04-21T01:13:02Z");
    let creds = EnvironmentProvider.credentials().wait().unwrap();
    assert_eq!(creds.expires_at().unwrap().to_rfc3339(), "2018-04-21T01:13:02+00:00");
}
  1. run
cargo build

I get the following build error:

   Compiling rusoto_s3_test v0.1.0 (file:///Users/oferaffias/Development/projects/Rust/rusoto_s3_test)
warning: unused import: `futures::future::Future`
 --> src/main.rs:4:5
  |
4 | use futures::future::Future;
  |     ^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: #[warn(unused_imports)] on by default

error[E0599]: no method named `wait` found for type `rusoto_credential::environment::EnvironmentProviderFuture` in the current scope
  --> src/main.rs:13:51
   |
13 |     let creds = EnvironmentProvider.credentials().wait().unwrap();
   |                                                   ^^^^
   |
   = help: items from traits can only be used if the trait is in scope
help: the following trait is implemented but not in scope, perhaps add a `use` for it:
   |
4  | use futures::future::Future;
   |

error[E0599]: no method named `wait` found for type `rusoto_credential::environment::EnvironmentProviderFuture` in the current scope
  --> src/main.rs:21:51
   |
21 |     let creds = EnvironmentProvider.credentials().wait().unwrap();
   |                                                   ^^^^
   |
   = help: items from traits can only be used if the trait is in scope
help: the following trait is implemented but not in scope, perhaps add a `use` for it:
   |
4  | use futures::future::Future;
   |

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0599`.
error: Could not compile `rusoto_s3_test`.

Any ideas?

2

rusoto_credential uses a different futures version than your crate. (0.1 and 0.2). You import version 0.2 Future while rusoto_credential only implements version 0.1 Future

3

Thanks! that worked, just for future reference, how should I read the compiler error? Does it mean there are two versions of futures::future::Future?

4

The combinators were moved to a new trait, FutureExt, in 0.2. In addition, wait() was removed.

The compiler sees that EnvironmentProviderFuture implements Future, and suggests importing it to make wait available. However, the Future you actually have is a different one, which doesn’t have wait() on it.

This is also why it emits an unused warning on the import - nothing is actually used from Future as it’s defined in 0.2.

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