README.md

Purpose

Use aws profile definition from ~/.aws/config and ~/.aws/credentials in rusoto, exactly like aws cli and aws official SDKs.

Related issues

rusoto/rusoto#1559 rusoto/rusoto#1758

credentials.rs

use std::collections::HashMap;
use std::env::var as env_var;
use std::fs;
use std::fs::File;
use std::io::{BufRead, BufReader};
use std::path::{Path, PathBuf};
use std::str::FromStr;
use std::sync::Arc;

use regex::Regex;
use rusoto_core::{HttpClient, Region};
use rusoto_credential::{AutoRefreshingProvider, CredentialsError, ProfileProvider};
use rusoto_sts::{StsAssumeRoleSessionCredentialsProvider, StsClient};
use dirs::home_dir;

const SOURCE_PROFILE: &str = "source_profile";
const ROLE_ARN: &str = "role_arn";

pub fn create_assume_role_profile(default_region: Region, session_name: String) -> Option<Arc<AutoRefreshingProvider<StsAssumeRoleSessionCredentialsProvider>>> {
    let config = parse_config_file(default_profile_location().ok()?.as_path())?;
    let source_profile_name = config
        .get(&default_profile_name())
        .and_then(|props| props.get(SOURCE_PROFILE))
        .map(std::borrow::ToOwned::to_owned)?;
    let role_arn = config
        .get(&default_profile_name())
        .and_then(|props| props.get(ROLE_ARN))
        .map(std::borrow::ToOwned::to_owned)?;
    let source_profile = ProfileProvider::with_default_credentials(source_profile_name).ok()?;
    let source_profile_region_string = source_profile.region_from_profile().unwrap_or(None);
    let source_profile_region =
    if let Some(s) = source_profile_region_string {
        Region::from_str(&s).unwrap_or(default_region)
    } else {
        default_region
    };
    let sts = StsClient::new_with(
        HttpClient::new().unwrap(),
        source_profile,
        source_profile_region,
    );
    let provider = StsAssumeRoleSessionCredentialsProvider::new(
        sts,
        role_arn,
        session_name,
        None,
        None,
        None,
        None,
    );
    let arc = Arc::new(
        rusoto_credential::AutoRefreshingProvider::new(provider).ok()?
    );
    return Some(arc);
}

/////////////////////////////////////////
// Following definitions are from rusoto.

// Quoted from rusoto-credentials/profile.rs
const AWS_PROFILE: &str = "AWS_PROFILE";
const AWS_SHARED_CREDENTIALS_FILE: &str = "AWS_SHARED_CREDENTIALS_FILE";
const DEFAULT: &str = "default";

// Quoted from rusoto-credentials/profile.rs
fn new_profile_regex() -> Regex {
    Regex::new(r"^\[(profile )?([^\]]+)\]$").expect("Failed to compile regex")
}

// Quoted from rusoto-credentials/profile.rs
fn parse_config_file(file_path: &Path) -> Option<HashMap<String, HashMap<String, String>>> {
    match fs::metadata(file_path) {
        Err(_) => return None,
        Ok(metadata) => {
            if !metadata.is_file() {
                return None;
            }
        }
    };
    let profile_regex = new_profile_regex();
    let file = File::open(file_path).expect("expected file");
    let file_lines = BufReader::new(&file);
    let result: (HashMap<String, HashMap<String, String>>, Option<String>) = file_lines
        .lines()
        .filter_map(|line| {
            line.ok()
                .map(|l| l.trim_matches(' ').to_owned())
                .into_iter()
                .find(|l| !l.starts_with('#') && !l.is_empty())
        })
        .fold(Default::default(), |(mut result, profile), line| {
            if profile_regex.is_match(&line) {
                let caps = profile_regex.captures(&line).unwrap();
                let next_profile = caps.get(2).map(|value| value.as_str().to_string());
                (result, next_profile)
            } else {
                match &line
                    .splitn(2, '=')
                    .map(|value| value.trim_matches(' '))
                    .collect::<Vec<&str>>()[..]
                {
                    [key, value] if !key.is_empty() && !value.is_empty() => {
                        if let Some(current) = profile.clone() {
                            let values = result.entry(current).or_insert_with(HashMap::new);
                            (*values).insert((*key).to_string(), (*value).to_string());
                        }
                        (result, profile)
                    }
                    _ => (result, profile),
                }
            }
        });
    Some(result.0)
}

// Quoted from rusoto-credentials/profile.rs
fn default_profile_location() -> Result<PathBuf, CredentialsError> {
    let env = non_empty_env_var(AWS_SHARED_CREDENTIALS_FILE);
    match env {
        Some(path) => Ok(PathBuf::from(path)),
        None => hardcoded_profile_location(),
    }
}

// Quoted from rusoto-credentials/profile.rs
fn hardcoded_profile_location() -> Result<PathBuf, CredentialsError> {
    match home_dir() {
        Some(mut home_path) => {
            home_path.push(".aws");
            home_path.push("config"); /// <<<<<<<<<< NOTE: original value is "credentials", but now "config".
            Ok(home_path)
        }
        None => Err(CredentialsError::new("Failed to determine home directory.")),
    }
}

// Quoted from rusoto-credentials/profile.rs
fn default_profile_name() -> String {
    non_empty_env_var(AWS_PROFILE).unwrap_or_else(|| DEFAULT.to_owned())
}

// Quoted from rusoto-credentials/profile.rs
fn non_empty_env_var(name: &str) -> Option<String> {
    match env_var(name) {
        Ok(value) => {
            if value.is_empty() {
                None
            } else {
                Some(value)
            }
        }
        Err(_) => None,
    }
}

LICENSE

The MIT License (MIT)

Copyright (c) 2017 Rusoto Project Developers
Copyright (c) 2020 tomykaira

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.