rrd: move creation of serde value into api

there is now a 'extract_cached_data' which just returns
the data of the specified field, and an api function that converts
a list of fields to the correct serde value

this way we do not have to create a serde value in rrd/cache.rs
(makes for a better interface)

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

src/rrd/cache.rs

@@ -4,7 +4,6 @@ use std::sync::{RwLock};
 
 use anyhow::{format_err, Error};
 use lazy_static::lazy_static;
-use serde_json::{json, Value};
 
 use proxmox::tools::fs::{create_path, CreateOptions};
 
@@ -103,41 +102,18 @@ pub fn extract_lists(
     Ok((times, result))
 }
 
-pub fn extract_data(
+pub fn extract_cached_data(
     base: &str,
-    items: &[&str],
+    name: &str,
+    now: f64,
     timeframe: RRDTimeFrameResolution,
     mode: RRDMode,
-) -> Result<Value, Error> {
+) -> Option<(u64, u64, Vec<Option<f64>>)> {
-
-    let now = epoch_now_f64()?;
 
     let map = RRD_CACHE.read().unwrap();
 
-    let mut result = Vec::new();
+    match map.get(&format!("{}/{}", base, name)) {
-
+        Some(rrd) => Some(rrd.extract_data(now, timeframe, mode)),
-    for name in items.iter() {
+        None => None,
-        let rrd = match map.get(&format!("{}/{}", base, name)) {
-            Some(rrd) => rrd,
-            None => continue,
-        };
-        let (start, reso, list) = rrd.extract_data(now, timeframe, mode);
-        let mut t = start;
-        for index in 0..RRD_DATA_ENTRIES {
-            if result.len() <= index {
-                if let Some(value) = list[index] {
-                    result.push(json!({ "time": t, *name: value }));
-                } else {
-                    result.push(json!({ "time": t }));
-                }
-            } else {
-                if let Some(value) = list[index] {
-                    result[index][name] = value.into();
     }
 }
-            t += reso;
-        }
-    }
-
-    Ok(result.into())
-}