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fix(cli): rescale count-derived money when --override-count replaces a row's count - #1847
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…a row's count (#1844) ApplyCountOverride replaced a recommendation's Count and copied the rest of the struct wholesale, so every quantity derived from that count kept the value it had for the count the provider proposed. A row entering with Count=100 and EstimatedSavings=600 left as count=5 savings=600, a twentyfold overstatement. It runs upstream of --max-instances on both the default and the --input-csv path, so the cap's own rescale then computed its ratio against a corrupted base and preserved the error faithfully into the run summary, the purchase report, the CSV and the confirmation prompt. The four count-derived money fields now scale by the override ratio through common.ScaleRecommendationCosts, the same helper ApplyInstanceLimit and the coverage paths already use, rather than a second implementation of the same arithmetic. RecurringMonthlyCost is a *float64 and a nil stays nil. A row with a non-positive Count is left alone: there is no denominator to form a ratio from, and setting Count without scaling would reintroduce the same defect. Chaining the override with the cap now composes two ratios into a single net ratio against the provider's figures instead of scaling a wrong base. Savings Plans are exempted, Count included. Routing them through the helper would have scaled SavingsPlanDetails.HourlyCommitment by an instance count, and that field is what the SP purchase call actually buys, so --override-count 10 would have committed ten times the dollars. An SP commitment is priced in dollars per hour rather than in instances, its Count is a placeholder the parser pins at 1, and the flag is documented as an override for the selected RIs. Skipping also stops an SP consuming N units of the --max-instances budget for what is one commitment. On the scale-up direction the issue left open: unit prices are linear, so CommitmentCost stays true at any quantity, but savings only accrue on hours a matching instance actually runs, so units beyond the observed demand are billed and may save nothing. Not scaling is not the safer answer, it reports the money of a different quantity and understates what will be charged. Rows are therefore scaled and the extrapolation is named on stdout, against RecommendedCount where the provider recorded one and the row's own count otherwise. Skipped SPs and skipped non-positive rows are named too. Eight of the nine new tests fail pre-fix, none by panic, and the pre-existing table test passes unchanged on both sides. Each was mutation-verified individually against the committed fix and every failure is again by assertion: dropping the rescale fails the down and up directions, the caller aliasing test that reportInstanceLimit's pre-cap diff depends on, and the composition test; removing the SP exemption fails the SP and skip-reporting tests, which is what proves both directions rather than only the rescaling one; removing the non-positive guard yields +Inf and fails that guard and the skip report; making the extrapolation boundary ignore RecommendedCount fires the warning on an override back up to the provider's own proposal; coercing the nil monthly cost to zero fails with Expected nil, but got a pointer. The nil-RecurringMonthlyCost test is the one that passes pre-fix, being a directional guard against the fix fabricating a zero rather than a regression test, stated so the coverage is not overread. ProjectedCoverage and ProjectedUtilization are count-linear and still not re-derived here, exactly as after a cap (#1845). The stale justification on the #1830 SP truncation test is corrected in the same change: that test's route was --override-count, which no longer reaches it, and the live route is the --input-csv path building Service from the CSV column. Closes #1844
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ChangesCount Override Rescaling
Estimated code review effort: 3 (Moderate) | ~20 minutes Merge Risk: 🔵 Low · up to The change corrects count-derived monetary totals before instance limiting, preventing overstated savings and costs. It is otherwise mergeable with owner awareness that cmd/helpers.go still exceeds the repository’s 500-line limit and should be addressed separately. Sequence Diagram(s)sequenceDiagram
participant CLI
participant ApplyCountOverride
participant ApplyInstanceLimit
CLI->>ApplyCountOverride: apply --override-count
ApplyCountOverride->>ApplyCountOverride: rescale eligible costs and update Count
ApplyCountOverride-->>ApplyInstanceLimit: return recommendations
ApplyInstanceLimit->>ApplyInstanceLimit: apply max-instances scaling
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In `@cmd/helpers.go`:
- Around line 495-580: Move ApplyCountOverride, evidencedCount, and
reportCountOverride from cmd/helpers.go into a focused Go file within the cmd
package, preserving their behavior and the public ApplyCountOverride signature;
leave helpers.go under the 500-line guideline.
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ApplyCountOverride, evidencedCount and reportCountOverride move verbatim into cmd/helpers_count_override.go. The public signature is unchanged and every caller is in the same package, so nothing else moves and nothing is renamed. This is a pure move, verified as one rather than asserted: every added line except the six-line package and import header is byte-identical to a removed line, in the same order, and the source shrank by exactly the moved block plus its one blank separator. No logic, signature, name or comment changed. The three functions reference only common.Recommendation, common.IsSavingsPlan, common.ScaleRecommendationCosts and the package-level AppLogger, so the new file needs a single import and the source loses none. cmd/helpers.go goes from 881 to 794 lines, which is 19 below the 813 it stood at before this PR touched it: the 68 lines this branch added are back out along with the function they replaced. The new file is 92 lines. The file is still over the 500-line limit, as are five other non-test files in cmd/. That is pre-existing and systemic, tracked in #1834, and restructuring 813 lines of money-path code inside a correctness fix is the wrong risk and makes the behavior diff unreadable. Taking this branch's own additions back out is the part that belongs here. Test parity is asserted on the SET of test names and outcomes rather than on a count, comparing a run in a pristine worktree at the pre-move commit against one on this tree: identical names, identical outcomes, no additions, no removals. golangci-lint at the CI-pinned v2.10.1 reports 0 issues and gocyclo -over 10 is clean on both files, checked after the move because moving code changes which file the complexity is attributed to.
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@coderabbitai full review Requesting a full review rather than an incremental one: the attempt after the most recent push was rate-limited, so there is no verdict against the current head The commit since then addresses your file-size finding, narrowly. I declined the wider split with reasoning on the thread. Measured against State: CI green on One correction for the record: your comment states the file is 633 lines. The actual figures are 813 on |
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ApplyCountOverridereplaced a recommendation'sCountand copied the rest of the struct wholesale, so every quantity derived from that count kept the value it had for the count the provider proposed. A row entering withCount=100, EstimatedSavings=600left ascount=5 savings=600, a twentyfold overstatement. It runs upstream of--max-instanceson both the default and the--input-csvpath, so the cap's own rescale then computed its ratio against a corrupted base and preserved the error faithfully into the run summary, the purchase report, the CSV and the confirmation prompt.What changed
The four count-derived money fields now scale by the override ratio through
common.ScaleRecommendationCosts, the same helperApplyInstanceLimitand the coverage paths already use, rather than a second implementation of the same arithmetic.RecurringMonthlyCostis a*float64and a nil stays nil. A row with a non-positiveCountis left alone: there is no denominator to form a ratio from, and settingCountwithout scaling would reintroduce the same defect.Field enumeration, re-derived against current
mainEstimatedSavingsCommitmentCostOnDemandCostRecurringMonthlyCostSavingsPlanDetails.HourlyCommitmentSavingsPercentageBreakEvenMonthsRecommendedCountAverageInstancesUsedPerHour,RecommendedUtilization,ExistingCoveragePct,UsageHistoryProjectedCoverage/ProjectedUtilizationDataWarehouseDetails.NumberOfNodesproviders/aws/services/redshift/client.go:191buildsNodeCountfromrec.Count. Also #1845Savings Plans are exempt,
CountincludedRouting SPs through the helper would have scaled
SavingsPlanDetails.HourlyCommitmentby an instance count, and that field is whatsavingsplans/client.go:232actually buys, so--override-count 10would have committed ten times the dollars. An SP commitment is priced in dollars per hour rather than in instances, the parser pins itsCountat 1 (parser_sp.go:382), and the flag is documented as an override for "all selected RIs". Skipping also stops an SP consuming N units of the--max-instancesbudget for what is one commitment.Checked the other commitment types rather than assuming: GCP CUD
Countis vCPUs and drives the insert request, Azure RI is quantity-based. Both are count-denominated and scale correctly. AWS SP is the only dollar-denominated case, andcommon.IsSavingsPlanis the predicateapplyCoveragealready uses for exactly this distinction.The scale-up judgement call
The issue left this open, so to state the reasoning explicitly. Unit prices are linear with no volume tiering, so
CommitmentCoststays true at any quantity. Savings only accrue on hours a matching instance actually runs, so units beyond the observed demand are billed and may save nothing, which makes an extrapolated savings figure a number nobody measured.Not scaling is not the safer answer. It reports the money of a different quantity, and it understates what the run will be charged, which is the more dangerous direction on a money path. Capping savings while scaling costs was rejected: it needs bespoke arithmetic outside the shared helper, and it yields an internally inconsistent row where
EstimatedSavingsno longer relates toOnDemandCost - CommitmentCostandSavingsPercentageis stale. Refusing outright was rejected as too strong for a documented flag whose whole purpose is to override the provider.So rows are scaled and the extrapolation is disclosed on stdout. The boundary is the provider's own proposal (
RecommendedCount) where it recorded one, falling back to the row's current count where it did not (RecommendedCountis populated only on the AWS RI path). That distinction matters: a row sized down to 80 by--coveragefrom a proposal of 100 is still inside what the provider's figures cover, so overriding back up to 100 is interpolation and stays quiet. Skipped SPs and skipped non-positive rows are named too, so an operator who got a differently sized run than they asked for is told which rows the flag could not size.Ordering interaction with
--max-instancesThe override runs before the run-wide cap on both paths (
applyCoverageAndOverridesfor the default path,runToolFromCSVbeforescoreAndLimitCSVRecsfor--input-csv). No path applies it after the cap. There is no double-scaling: the two ratios compose to(remaining/N) * (N/orig) = remaining/orig, a single net ratio against the provider's figures, and the override now corrects the base before the cap derives its own ratio from it.TestApplyCountOverrideThenInstanceLimitScalesOncepins this against an independently computed expectation.A side effect worth naming:
--input-csvranks rows by savings-per-instance before the cap. Pre-fix, the override flattened every row's count so that ranking degenerated to rawEstimatedSavings; post-fix the per-instance rate is invariant under the override, so the cap keeps the genuinely best rows.Verification
Eight of the nine new tests fail pre-fix, none by panic, and the pre-existing
TestApplyCountOverridetable test passes unchanged on both sides. Each was mutation-verified individually against the committed fix, every failure again by assertion:RecommendedCountExpected nil, but got a pointerTestApplyCountOverridePreservesNilRecurringMonthlyCostis the one that passes pre-fix, being a directional guard against the fix fabricating a zero rather than a regression test, stated so the coverage is not overread.Caller aliasing is asserted as #1830 did:
reportInstanceLimitdiffs the pre-cap slice against the post-cap one, so a shared pointer target would corrupt drop reporting.go test ./cmd/855 passed,./pkg/...744 passed, all six workspace modules build,-raceclean on the new tests,golangci-lint runat the CI pin v2.10.1 reports 0 issues (exit 0),gocyclo -over 10 -ignore "_test\.go" .clean.Also in this change
The justification comment on
TestApplyInstanceLimitRescalesSavingsPlanHourlyCommitment(#1830) cited--override-countas the route by which an SP reaches the cap at a count above 1. That route no longer exists after this change, so it is corrected to the live one: the--input-csvpath buildsServicestraight from the CSV column, so a file naming a savingsplans service at a count above the budget still reaches that branch.Closes #1844
Summary by CodeRabbit
Enhancements
--override-countnow proportionally adjusts costs and savings for count-based recommendations.Documentation