fix(import): store SmokePing history under the configured target's id (#137)

`smoked import smokeping --apply` mints a UUID onto every imported target,
but `--history` stored each RRD's rows under the SmokePing path. The hub
resolves a target to its stable id, so the backfilled history never showed
on the target's graph or in /api/series.

`--history` now looks each SmokePing target up by path in the DB config
fragment and, when given, the YAML config passed with `--config`, and
stores its rows under that target's id. A target that matches no
configured target, or more than one (a path defined in both configs), is
named on stderr, counted as unresolved in the summary, and not imported;
the run exits 3 as for other partial failures. With no `--config` and no
targets in the DB config, rows keep their SmokePing path keys (the id of
a YAML target without an explicit id) and the run prints a note.

config.TargetIdentities lists each host node's path and storage id
exactly as Monitors names them, without inheritance or validation, so a
DB fragment can be indexed on its own; Monitors now shares its path and
id helpers.

Author: seitzbg

CHANGELOG.md

@@ -28,6 +28,16 @@ All notable changes to **Heliograph** are recorded here. The format follows
   measurement. A target that only gains an alert on reload is still warm-started. On a cold start,
   smoked has no record of a target's previous definition, so a target redefined while smoked was
   stopped can still be warm-started from its recent old rounds.
+- **`smoked import smokeping --history` now stores history where the target's graph reads it.**
+  `--apply` gives every imported target a new stable id, but `--history` stored each RRD's rows
+  under the SmokePing path, so the backfilled history never appeared on the configured target's
+  graph or in `/api/series`. `--history` now looks each target up by path in the DB config and, when
+  given, the YAML config passed with `--config`, and stores its rows under that target's id. A target
+  that matches no configured target, or more than one, is named on stderr, counted as `unresolved`
+  in the summary, and not imported; the run then exits `3`, the same as other partial failures.
+  With no `--config` and no targets in the DB config, rows are still keyed by SmokePing path, which
+  matches a YAML target that has no `id`, and the run says so. History already imported under
+  SmokePing paths is not moved; re-run `--history` to store it under the target ids.
 
 ### Security
 - **Revoking and re-adding a vantage now retires its earlier certificates.** Agent authorization

README.md

@@ -245,6 +245,33 @@ SMOKE_TEST_DSN='postgres://smoke:smoke@127.0.0.1:5433/smoke?sslmode=disable' \
 
 The schema (one `samples` hypertable) is created automatically on first connect.
 
+### Migrating from SmokePing
+
+`smoked import smokeping <config-dir>` converts a SmokePing `Targets`/`Probes`/`Database` config
+into a Heliograph target tree. Import the config first, then the RRD history:
+
+```sh
+DSN='postgres://user:pass@host:5432/smoke?sslmode=disable'
+smoked import smokeping /etc/smokeping/config --out smokeping.yaml   # review the converted tree
+smoked import smokeping /etc/smokeping/config --apply --dsn "$DSN"   # merge it into the DB config
+smoked import smokeping /etc/smokeping/config --report               # dry run: which targets have .rrd files
+smoked import smokeping /etc/smokeping/config --history --dsn "$DSN" # backfill the RRD history
+```
+
+`--history` needs `rrdtool` and a database where downsampling is already on (`smoked -downsample`).
+It reads the RRD files from `<config-dir>/../data` or `<config-dir>/data`; pass `--data` to point
+elsewhere. Each SmokePing target's history is stored under the id of the configured target at the
+same path, so it shows on that target's graph. `--apply` gives every imported target a new id, so
+run `--history` after `--apply`. If you put the converted tree in your YAML config instead (for
+example as a `conf.d/` file), pass that config with `--config` so explicit `id`s there are honored.
+With no `--config` and no targets in the DB config, history is stored under the SmokePing path,
+which is the id of a YAML target with no `id`.
+
+`--history` skips a target and names it on stderr when no configured target has its path (renamed
+or moved since the config import) or when more than one does. It also skips a target whose ping
+count can't be resolved or whose RRD can't be read. The other targets are still imported, and the
+run exits `3` if any target was skipped for one of these reasons.
+
 ### Federation deployment (reverse proxy)
 
 Remote **vantages** (the `smoke-agent` collector) reach the hub over two independent surfaces

ROADMAP.md

@@ -157,7 +157,10 @@ Phase-6 items all ship in the single **v1.0** line.
     `data` subdir); `--history` extracts each matched target's full RRD history via `rrdtool` and
     backfills median/loss into `samples` + the hourly/daily aggregates, idempotently. Requires the
     continuous aggregates already enabled (`smoked -downsample`) — refuses to import (no rows
-    written) otherwise, so old history is never left unmaterialized ahead of raw retention
+    written) otherwise, so old history is never left unmaterialized ahead of raw retention.
+    Rows are stored under the stable id of the configured target at the same path (DB config,
+    plus the YAML config given with `--config`); a target with no single match is reported and
+    skipped (Unreleased)
 - ✅ **Native ICMP probe** — a new `Ping` probe kind (`internal/probe/pingprobe`) speaks ICMP
   echo itself via `golang.org/x/net/icmp`: datagram socket first (unprivileged, needs the
   `net.ipv4.ping_group_range` sysctl), raw-socket fallback (`CAP_NET_RAW`). Ships alongside