Fix style suggestions and add some error handling logs

src/Exceptions/MetricRequestFailedException.cs

@@ -4,4 +4,7 @@ public class MetricRequestFailedException : Exception
 {
     public MetricRequestFailedException(string message) : base(message)
     { }
+
+    public MetricRequestFailedException(string message, Exception innerException) : base(message, innerException)
+    { }
 }

src/Program.cs

@@ -134,9 +134,11 @@
         })
         .ConfigurePrimaryHttpMessageHandler(_ =>
         {
-            var handler = new HttpClientHandler();
-            // Tesla Gateway serves a self-signed cert
-            handler.ServerCertificateCustomValidationCallback = (_, _, _, _) => true;
+            var handler = new HttpClientHandler
+            {
+                // Tesla Gateway serves a self-signed cert
+                ServerCertificateCustomValidationCallback = (_, _, _, _) => true
+            };
             return handler;
         })
         .UseHttpClientMetrics()

src/Services/EnphaseMetricsService.cs

@@ -12,26 +12,18 @@ namespace SolarGateway_PrometheusProxy.Services;
 /// This class was built by doing limited reverse engineering of a friend's Enphase gateway.
 /// There may be more metrics available with additional investigation.
 /// </remarks>
-public class EnphaseMetricsService : MetricsServiceBase
+public class EnphaseMetricsService(
+    HttpClient httpClient,
+    ILogger<EnphaseMetricsService> logger) : MetricsServiceBase(httpClient, logger)
 {
-    public EnphaseMetricsService(
-        HttpClient httpClient,
-        ILogger<EnphaseMetricsService> logger)
-        : base(httpClient, logger)
-    { }
-
     protected override string MetricCategory => "enphase";
 
     public override async Task CollectMetricsAsync(CollectorRegistry collectorRegistry, CancellationToken cancellationToken = default)
     {
         var sw = Stopwatch.StartNew();
 
-        using var metricsDocument = await base.CallMetricEndpointAsync("/production.json", () => null, cancellationToken);
-        if (metricsDocument == null)
-        {
-            throw new MetricRequestFailedException($"Failed to pull metric endpoint endpoints on Enphase gateway");
-        }
-
+        using var metricsDocument = (await base.CallMetricEndpointAsync("/production.json", () => null, cancellationToken))
+            ?? throw new MetricRequestFailedException($"Failed to pull metric endpoint endpoints on Enphase gateway");
         var production = metricsDocument.RootElement
             .GetProperty("production")
             .EnumerateArray()

src/Services/MetricsServiceBase.cs

@@ -1,6 +1,7 @@
 using System.Net.Http.Headers;
 using System.Text.Json;
 using Prometheus;
+using SolarGateway_PrometheusProxy.Exceptions;
 using SolarGateway_PrometheusProxy.Models;
 
 namespace SolarGateway_PrometheusProxy.Services;
@@ -22,8 +23,8 @@ public MetricsServiceBase(HttpClient client, ILogger logger)
 
     protected Gauge.Child CreateGauge(CollectorRegistry registry, string subCategory, string metric, params KeyValuePair<string, string>[] labels)
     {
-        var labelKeys = labels.Select(l => l.Key).Concat(new[] { $"{this.GetType().Name}Host" }).ToArray();
-        var labelValues = labels.Select(l => l.Value).Concat(new[] { _client.BaseAddress!.Host }).ToArray();
+        var labelKeys = labels.Select(l => l.Key).Concat([$"{this.GetType().Name}Host"]).ToArray();
+        var labelValues = labels.Select(l => l.Value).Concat([_client.BaseAddress!.Host]).ToArray();
         return Metrics.WithCustomRegistry(registry).CreateGauge($"solarapiproxy_{MetricCategory}_{subCategory}_{metric}", metric, labelKeys)
                       .WithLabels(labelValues);
     }
@@ -47,21 +48,28 @@ protected void SetRequestDurationMetric(CollectorRegistry registry, bool loginCa
 
     protected async Task<JsonDocument?> CallMetricEndpointAsync(string path, Func<AuthenticationHeaderValue?> authenticationCallback, CancellationToken cancellationToken)
     {
-        using var request = new HttpRequestMessage(HttpMethod.Get, path);
-        var authHeader = authenticationCallback();
-        if (authHeader != null)
+        try
         {
-            request.Headers.Authorization = authHeader;
-        }
+            using var request = new HttpRequestMessage(HttpMethod.Get, path);
+            var authHeader = authenticationCallback();
+            if (authHeader != null)
+            {
+                request.Headers.Authorization = authHeader;
+            }
+
+            using var response = await _client.SendAsync(request, HttpCompletionOption.ResponseHeadersRead, cancellationToken);
 
-        using var response = await _client.SendAsync(request, HttpCompletionOption.ResponseHeadersRead, cancellationToken);
+            if (!response.IsSuccessStatusCode)
+            {
+                _logger.LogError($"Got {response.StatusCode} calling '{path}': {await response.Content.ReadAsStringAsync()}");
+                return null;
+            }
 
-        if (!response.IsSuccessStatusCode)
+            return await response.Content.ReadFromJsonAsync<JsonDocument>(JsonModelContext.Default.JsonDocument, cancellationToken);
+        }
+        catch (Exception ex)
         {
-            _logger.LogError($"Got {response.StatusCode} calling '{path}': {await response.Content.ReadAsStringAsync()}");
-            return null;
+            throw new MetricRequestFailedException(ex.Message, ex);
         }
-
-        return await response.Content.ReadFromJsonAsync<JsonDocument>(JsonModelContext.Default.JsonDocument, cancellationToken);
     }
 }

src/Services/TeslaGatewayMetricsService.cs

@@ -12,24 +12,16 @@ namespace SolarGateway_PrometheusProxy.Services;
 /// <summary>
 /// Provides metrics from a Tesla Gateway and saves them to a Prometheus <see cref="CollectorRegistry"/>.
 /// </summary>
-public partial class TeslaGatewayMetricsService : MetricsServiceBase
+public partial class TeslaGatewayMetricsService(
+    HttpClient httpClient,
+    IOptions<TeslaConfiguration> configuration,
+    IOptions<TeslaLoginRequest> loginRequest,
+    ILogger<TeslaGatewayMetricsService> logger,
+    IMemoryCache cache) : MetricsServiceBase(httpClient, logger)
 {
-    private readonly TeslaLoginRequest _loginRequest;
-    private readonly IMemoryCache _cache;
-    private readonly TimeSpan _loginCacheLength;
-
-    public TeslaGatewayMetricsService(
-        HttpClient httpClient,
-        IOptions<TeslaConfiguration> configuration,
-        IOptions<TeslaLoginRequest> loginRequest,
-        ILogger<TeslaGatewayMetricsService> logger,
-        IMemoryCache cache)
-        : base(httpClient, logger)
-    {
-        _loginRequest = loginRequest.Value;
-        _cache = cache;
-        _loginCacheLength = TimeSpan.FromMinutes(configuration.Value.LoginCacheMinutes);
-    }
+    private readonly TeslaLoginRequest _loginRequest = loginRequest.Value;
+    private readonly IMemoryCache _cache = cache;
+    private readonly TimeSpan _loginCacheLength = TimeSpan.FromMinutes(configuration.Value.LoginCacheMinutes);
 
     protected override string MetricCategory => "tesla_gateway";
 
@@ -89,6 +81,7 @@ private async Task<bool> PullMeterAggregates(CollectorRegistry registry, TeslaLo
         using var metricsDocument = await base.CallMetricEndpointAsync("/api/meters/aggregates", loginResponse.ToAuthenticationHeader, cancellationToken);
         if (metricsDocument is null)
         {
+            this._logger.LogError("API Meter aggregates document is null");
             return false;
         }
 
@@ -124,6 +117,7 @@ private async Task<bool> PullPowerwallPercentage(CollectorRegistry registry, Tes
         using var metricsDocument = await base.CallMetricEndpointAsync("/api/system_status/soe", loginResponse.ToAuthenticationHeader, cancellationToken);
         if (metricsDocument is null)
         {
+            this._logger.LogError("API Powerwall percentage document is null");
             return false;
         }
 
@@ -136,6 +130,7 @@ private async Task<bool> PullSiteInfo(CollectorRegistry registry, TeslaLoginResp
         using var metricsDocument = await base.CallMetricEndpointAsync("/api/site_info", loginResponse.ToAuthenticationHeader, cancellationToken);
         if (metricsDocument is null)
         {
+            this._logger.LogError("Site info document is null");
             return false;
         }
 
@@ -156,6 +151,7 @@ private async Task<bool> PullStatus(CollectorRegistry registry, TeslaLoginRespon
         using var metricsDocument = await base.CallMetricEndpointAsync("/api/status", loginResponse.ToAuthenticationHeader, cancellationToken);
         if (metricsDocument is null)
         {
+            this._logger.LogError("API Status document is null");
             return false;
         }
 
@@ -182,13 +178,14 @@ private async Task<bool> PullOperation(CollectorRegistry registry, TeslaLoginRes
         using var metricsDocument = await base.CallMetricEndpointAsync("/api/operation", loginResponse.ToAuthenticationHeader, cancellationToken);
         if (metricsDocument is null)
         {
+            this._logger.LogError("API Operation document is null");
             return false;
         }
 
         base.CreateGauge(registry, "operation", "backup_reserve_percent").Set(metricsDocument.RootElement.GetProperty("backup_reserve_percent").GetDouble());
 
         string? realMode = metricsDocument.RootElement.GetProperty("real_mode").GetString();
-        Func<string, Gauge.Child> GetModeGauge = (mode) => base.CreateGauge(registry, "operation", "mode", KeyValuePair.Create("mode", mode));
+        Gauge.Child GetModeGauge(string mode) => base.CreateGauge(registry, "operation", "mode", KeyValuePair.Create("mode", mode));
 
         const string selfConsumption = "self_consumption", autonomous = "autonomous", backup = "backup";
         GetModeGauge(selfConsumption).Set(realMode == selfConsumption ? 1 : 0);