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static URL: &str = "https://cloud-images.ubuntu.com/locator/ec2/releasesTable?_=1588199609256";
pub type StdError = Box<dyn std::error::Error + Send + Sync + 'static>;
#[derive(Debug, Clone)]
struct Entry {
region: String,
release_name: String,
release_number: String,
architecture: String,
instance_type: String,
date: String,
ami: String,
hvm: String,
}
pub async fn get_latest(
region: &str,
release_name: Option<&str>,
release_number: Option<&str>,
instance_type: Option<&str>,
architecture: Option<&str>,
) -> Result<String, StdError> {
let mut r = reqwest::get(URL).await?.text().await?;
let len = r.len();
let (first, last) = r.split_at_mut(len - 10);
let mut r = first.to_string();
r.extend(last.replace(',', " ").chars());
let j: serde_json::Value = serde_json::from_str(&r)?;
let amis = j
.as_object()
.ok_or_else(|| String::from("Value not a JSON object"))?
.values()
.next()
.unwrap();
let mut amis: Vec<Entry> = amis
.as_array()
.ok_or_else(|| String::from("Value not a JSON array"))?
.into_iter()
.map(|v| {
let fs: Vec<&str> = v
.as_array()
.unwrap()
.into_iter()
.map(|s| s.as_str().unwrap())
.collect();
Entry {
region: fs[0].to_string(),
release_name: fs[1].to_string(),
release_number: fs[2].to_string(),
architecture: fs[3].to_string(),
instance_type: fs[4].to_string(),
date: fs[5].to_string(),
ami: fs[6].to_string(),
hvm: fs[7].to_string(),
}
})
.filter(|e| e.region == region)
.filter(|e| {
if let Some(release_name) = release_name {
e.release_name == release_name
} else {
true
}
})
.filter(|e| {
if let Some(release_number) = release_number {
e.release_number == release_number
} else {
true
}
})
.filter(|e| {
if let Some(instance_type) = instance_type {
e.instance_type == instance_type
} else {
true
}
})
.filter(|e| {
if let Some(architecture) = architecture {
e.architecture == architecture
} else {
true
}
})
.collect();
amis.sort_by_key(|e| e.date.clone());
let entry = amis
.pop()
.ok_or_else(|| anyhow::anyhow!("Could not find ami for criteria"))?;
Ok(parse_ami(&entry.ami)
.ok_or_else(|| anyhow::anyhow!("Failure parsing ami"))?
.to_string())
}
fn parse_ami(a_tag: &str) -> Option<&str> {
let start_idx = a_tag.find("ami-")?;
let end_idx = a_tag[start_idx + 4..].find(|c: char| !c.is_alphanumeric())? + start_idx + 4;
Some(&a_tag[start_idx..end_idx])
}
#[cfg(test)]
mod test {
use super::parse_ami;
#[test]
fn test_ami_parse() {
let html = "<a href=\"https://console.aws.amazon.com/ec2/home?region=us-east-1#launchAmi=ami-085925f297f89fce1\">ami-085925f297f89fce1</a>";
let ami = parse_ami(html).unwrap();
assert_eq!(ami, "ami-085925f297f89fce1");
}
}