feat: add process metrics (#30)

Author: mempirate

.github/workflows/test.yml

@@ -28,7 +28,7 @@ jobs:
           cache-on-failure: true
       - uses: taiki-e/install-action@nextest
       - name: Run unit tests
-        run: cargo nextest run --lib --no-tests=warn
+        run: cargo nextest run --lib --all-features --no-tests=warn
   integration-test:
     name: integration tests
     runs-on: ubuntu-latest
@@ -43,4 +43,4 @@ jobs:
           cache-on-failure: true
       - uses: taiki-e/install-action@nextest
       - name: Run integration tests
-        run: cargo nextest run --tests
+        run: cargo nextest run --tests --all-features

Cargo.lock

@@ -60,6 +60,43 @@ metrics.account_balance("1234567890").set(-12.2);
 metrics.errors().inc();
 ```
 
+#### Sample Output
+
+```text
+# HELP app_account_balance The balance of the account, in dollars. Uses a floating point number.
+# TYPE app_account_balance gauge
+app_account_balance{account_id="1234567890",host="localhost",port="8080"} -12.2
+
+# HELP app_current_active_users The current number of active users.
+# TYPE app_current_active_users gauge
+app_current_active_users{host="localhost",port="8080",service="service-1"} 20
+
+# HELP app_errors The total number of errors.
+# TYPE app_errors counter
+app_errors{host="localhost",port="8080"} 1
+
+# HELP app_http_requests_duration The duration of HTTP requests.
+# TYPE app_http_requests_duration histogram
+app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="0.005"} 0
+app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="0.01"} 0
+app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="0.025"} 0
+app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="0.05"} 0
+app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="0.1"} 0
+app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="0.25"} 0
+app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="0.5"} 0
+app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="1"} 1
+app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="2.5"} 1
+app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="5"} 1
+app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="+Inf"} 1
+app_http_requests_duration_sum{host="localhost",method="GET",path="/",port="8080"} 1
+app_http_requests_duration_count{host="localhost",method="GET",path="/",port="8080"} 1
+
+# HELP app_http_requests_total The total number of HTTP requests.
+# TYPE app_http_requests_total counter
+app_http_requests_total{host="localhost",method="GET",path="/",port="8080"} 2
+app_http_requests_total{host="localhost",method="POST",path="/",port="8080"} 2
+```
+
 ### Static Metrics
 
 You can also generate a static `LazyLock` instance by using the `static` attribute. When enabled, the builder methods and `Default` implementation are made private, ensuring the only way to access the metrics is through the static instance:
@@ -106,39 +143,49 @@ ExporterBuilder::new()
     .expect("Failed to install exporter");
 ```
 
-#### Sample Output
+### Process Metrics
 
-```text
-# HELP app_account_balance The balance of the account, in dollars. Uses a floating point number.
-# TYPE app_account_balance gauge
-app_account_balance{account_id="1234567890",host="localhost",port="8080"} -12.2
+When the `process` feature is enabled, the `ProcessCollector` can be used to collect metrics about the current process.
 
-# HELP app_current_active_users The current number of active users.
-# TYPE app_current_active_users gauge
-app_current_active_users{host="localhost",port="8080",service="service-1"} 20
+```rust
+use prometric::process::ProcessCollector;
+use prometric_derive::metrics;
 
-# HELP app_errors The total number of errors.
-# TYPE app_errors counter
-app_errors{host="localhost",port="8080"} 1
+let collector = ProcessCollector::default();
+collector.collect();
+```
 
-# HELP app_http_requests_duration The duration of HTTP requests.
-# TYPE app_http_requests_duration histogram
-app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="0.005"} 0
-app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="0.01"} 0
-app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="0.025"} 0
-app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="0.05"} 0
-app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="0.1"} 0
-app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="0.25"} 0
-app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="0.5"} 0
-app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="1"} 1
-app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="2.5"} 1
-app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="5"} 1
-app_http_requests_duration_bucket{host="localhost",method="GET",path="/",port="8080",le="+Inf"} 1
-app_http_requests_duration_sum{host="localhost",method="GET",path="/",port="8080"} 1
-app_http_requests_duration_count{host="localhost",method="GET",path="/",port="8080"} 1
+#### Sample Output
 
-# HELP app_http_requests_total The total number of HTTP requests.
-# TYPE app_http_requests_total counter
-app_http_requests_total{host="localhost",method="GET",path="/",port="8080"} 2
-app_http_requests_total{host="localhost",method="POST",path="/",port="8080"} 2
-```
+```text
+# HELP process_cpu_usage The CPU usage of the process as a percentage.
+# TYPE process_cpu_usage gauge
+process_cpu_usage 0.7814099788665771
+# HELP process_disk_written_bytes_total The total written bytes to disk by the process.
+# TYPE process_disk_written_bytes_total gauge
+process_disk_written_bytes_total 0
+# HELP process_max_cpu_freq The maximum CPU frequency of all cores in MHz.
+# TYPE process_max_cpu_freq gauge
+process_max_cpu_freq 4464
+# HELP process_max_fds The maximum number of open file descriptors of the process.
+# TYPE process_max_fds gauge
+process_max_fds 10240
+# HELP process_min_cpu_freq The minimum CPU frequency of all cores in MHz.
+# TYPE process_min_cpu_freq gauge
+process_min_cpu_freq 4464
+# HELP process_open_fds The number of open file descriptors of the process.
+# TYPE process_open_fds gauge
+process_open_fds 45
+# HELP process_resident_memory_bytes The resident memory of the process in bytes. (RSS)
+# TYPE process_resident_memory_bytes gauge
+process_resident_memory_bytes 4603904
+# HELP process_resident_memory_usage The resident memory usage of the process as a percentage of the total memory available.
+# TYPE process_resident_memory_usage gauge
+process_resident_memory_usage 0.00013399124145507813
+# HELP process_start_time_seconds The start time of the process in UNIX seconds.
+# TYPE process_start_time_seconds gauge
+process_start_time_seconds 1762338704
+# HELP process_threads The number of OS threads used by the process (Linux only).
+# TYPE process_threads gauge
+process_threads 1
+```