refactor(kms): extract generic http_get/http_post helpers

- Unify User-Agent, status check, body truncation, and decode error
  context into a single send_request function
- Both is_app_allowed and get_info now share consistent error handling
- Truncate response body to 512 bytes in error messages to avoid
  noisy HTML pages in logs
- Remove separate http_client() function

Author: kvinwang

kms/src/main_service/upgrade_authority.rs

@@ -5,6 +5,7 @@
 use crate::config::AuthApi;
 use anyhow::{bail, Context, Result};
 use ra_tls::attestation::AttestationMode;
+use serde::de::DeserializeOwned;
 use serde::{Deserialize, Serialize};
 use serde_human_bytes as hex_bytes;
 
@@ -60,12 +61,26 @@ pub(crate) struct GetInfoResponse {
     pub app_implementation: Option<String>,
 }
 
-fn http_client() -> Result<reqwest::Client> {
+async fn http_get<R: DeserializeOwned>(url: &str) -> Result<R> {
+    send_request(reqwest::Client::new().get(url), url).await
+}
+
+async fn http_post<R: DeserializeOwned>(url: &str, body: &impl Serialize) -> Result<R> {
+    send_request(reqwest::Client::new().post(url).json(body), url).await
+}
+
+async fn send_request<R: DeserializeOwned>(req: reqwest::RequestBuilder, url: &str) -> Result<R> {
     static USER_AGENT: &str = concat!("dstack-kms/", env!("CARGO_PKG_VERSION"));
-    reqwest::Client::builder()
-        .user_agent(USER_AGENT)
-        .build()
-        .context("failed to build http client")
+    let response = req.header("User-Agent", USER_AGENT).send().await?;
+    let status = response.status();
+    let body = response.text().await?;
+    let short_body = &body[..body.len().min(512)];
+    if !status.is_success() {
+        bail!("auth api {url} returned {status}: {short_body}");
+    }
+    serde_json::from_str(&body).with_context(|| {
+        format!("failed to decode response from {url}, status={status}, body={short_body}")
+    })
 }
 
 impl AuthApi {
@@ -77,18 +92,13 @@ impl AuthApi {
                 gateway_app_id: dev.gateway_app_id.clone(),
             }),
             AuthApi::Webhook { webhook } => {
-                let client = http_client()?;
                 let path = if is_kms {
                     "bootAuth/kms"
                 } else {
                     "bootAuth/app"
                 };
                 let url = url_join(&webhook.url, path);
-                let response = client.post(&url).json(&boot_info).send().await?;
-                if !response.status().is_success() {
-                    bail!("Failed to check boot auth: {}", response.text().await?);
-                }
-                Ok(response.json().await?)
+                http_post(&url, &boot_info).await
             }
         }
     }
@@ -103,16 +113,7 @@ impl AuthApi {
                 app_implementation: None,
             }),
             AuthApi::Webhook { webhook } => {
-                let client = http_client()?;
-                let response = client.get(&webhook.url).send().await?;
-                let status = response.status();
-                let body = response.text().await?;
-                let info: AuthApiInfoResponse = serde_json::from_str(&body).with_context(|| {
-                    format!(
-                        "failed to decode auth api response from {}, status={status}, body={body}",
-                        webhook.url
-                    )
-                })?;
+                let info: AuthApiInfoResponse = http_get(&webhook.url).await?;
                 Ok(GetInfoResponse {
                     is_dev: false,
                     kms_contract_address: Some(info.kms_contract_addr.clone()),