milestone 30: overview as a dashboard, explicit health contract, period aggregations

src/web/metrics.zig

@@ -31,7 +31,6 @@ const dns_handler = @import("../server/handler.zig");
 const disk_monitor = @import("../storage/disk_monitor.zig");
 const dot_server = @import("../server/dot_server.zig");
 const events_mod = @import("../storage/events.zig");
-const history_mod = @import("../upstream/history.zig");
 const http_util = @import("http_util.zig");
 const logging = @import("../platform/logging.zig");
 const pool_mod = @import("../upstream/pool.zig");
@@ -136,9 +135,6 @@ pub const Sample = struct {
     tracker: ?TrackerSample = null,
     client_names: ?client_names.Resolver.Stats = null,
     retention: ?retention_mod.Stats = null,
-    /// The upstream-history flush loop's counters (m26 ruling 7). Absent while
-    /// no accumulator is wired, like every other collaborator.
-    history: ?history_mod.Accumulator.Stats = null,
     /// The diagnostics store's open episodes and its failed writes. Absent
     /// while no store is wired, like every other collaborator — an operator
     /// distinguishes "no series" from "zero episodes" through `/api/health`,
@@ -218,8 +214,6 @@ pub fn collect(state: *server.WebState, io: std.Io, arena: Allocator) Allocator.
 
     if (state.retention) |retention| sample.retention = retention.snapshotStats();
 
-    if (state.history) |history| sample.history = history.snapshotStats(io);
-
     if (state.events) |store| {
         const counts = store.activeCounts(io);
         sample.diagnostics = .{
@@ -382,36 +376,6 @@ pub fn render(w: *std.Io.Writer, sample: Sample) std.Io.Writer.Error!void {
         try counterGroup(w, "nxdns_retention_", "Query log retention counter", retention);
     }
 
-    if (sample.history) |history| {
-        // Written out rather than reflected over `Accumulator.Stats`: three of
-        // its fields are counters, one is a gauge, and two — the drop watermark
-        // and the current flush state — are not exposition numbers at all.
-        try counter(
-            w,
-            "nxdns_upstream_history_flushes_total",
-            "Upstream history flush transactions that committed.",
-            history.flushes,
-        );
-        try counter(
-            w,
-            "nxdns_upstream_history_flush_failures_total",
-            "Upstream history flush attempts that failed; the rows are retried on the next pass.",
-            history.flush_failures,
-        );
-        try counter(
-            w,
-            "nxdns_upstream_history_rows_dropped_total",
-            "Upstream history minutes dropped because the accumulator was full.",
-            history.rows_dropped,
-        );
-        try gauge(
-            w,
-            "nxdns_upstream_history_pending",
-            "Upstream history minutes recorded but not yet flushed.",
-            history.pending,
-        );
-    }
-
     if (sample.diagnostics) |diagnostics| {
         try gauge(
             w,
@@ -638,7 +602,7 @@ fn writeUpstreamLabels(
 /// through this function too, so the guarantee cannot be one caller away.
 /// `UpstreamSample.url` stays whole for the same reason it is safe to: nothing
 /// but this function reads it, and the session-authenticated
-/// `GET /api/upstream/health` reports the same pool with the same urls whole.
+/// `GET /api/upstreams` reports the same urls whole.
 ///
 /// **`redact` output is not safe to interpolate into a label value, and this
 /// function is the reason it never has to be.** Do not delete the second layer
@@ -803,31 +767,6 @@ test "a full sample renders the whole exposition, byte for byte" {
     ));
 }
 
-test "the upstream-history family renders three counters and one gauge" {
-    const text = try renderToString(testing.allocator, .{
-        .history = .{
-            .flushes = 12,
-            .flush_failures = 2,
-            .rows_dropped = 5,
-            .pending = 3,
-            .last_drop_minute = 1_700_000_040,
-            .last_flush_failed = true,
-        },
-    });
-    defer testing.allocator.free(text);
-
-    try testing.expect(std.mem.containsAtLeast(u8, text, 1, "nxdns_upstream_history_flushes_total 12\n"));
-    try testing.expect(std.mem.containsAtLeast(u8, text, 1, "nxdns_upstream_history_flush_failures_total 2\n"));
-    try testing.expect(std.mem.containsAtLeast(u8, text, 1, "nxdns_upstream_history_rows_dropped_total 5\n"));
-    try testing.expect(std.mem.containsAtLeast(u8, text, 1, "# TYPE nxdns_upstream_history_pending gauge\n"));
-    try testing.expect(std.mem.containsAtLeast(u8, text, 1, "nxdns_upstream_history_pending 3\n"));
-
-    // No accumulator is an absent family, not a family of zeros.
-    const bare = try renderToString(testing.allocator, .{});
-    defer testing.allocator.free(bare);
-    try testing.expect(!std.mem.containsAtLeast(u8, bare, 1, "nxdns_upstream_history_"));
-}
-
 test "the diagnostics family renders two gauges and one counter" {
     const text = try renderToString(testing.allocator, .{
         .diagnostics = .{ .active_warnings = 3, .active_errors = 1, .write_failures = 7 },