lib: cmetrics: upgrade to v2.1.2#11685
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📝 WalkthroughWalkthroughThis PR increments the CMetrics patch version and adds strict validation for Prometheus histogram buckets by requiring a non-empty "le" label value; a unit test was added to assert failure when "le" is missing. Changes
Sequence Diagram(s)(omitted) Estimated code review effort🎯 3 (Moderate) | ⏱️ ~20 minutes Suggested reviewers
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🚥 Pre-merge checks | ✅ 2 | ❌ 1❌ Failed checks (1 warning)
✅ Passed checks (2 passed)
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🧪 Generate unit tests (beta)
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Actionable comments posted: 2
🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.
Inline comments:
In `@lib/cmetrics/CMakeLists.txt`:
- Line 9: The CMake file sets CMT_VERSION_PATCH to 2 but the official
fluent/cmetrics latest release is v2.0.5, so update the patch constant to match
the real upstream tag (change CMT_VERSION_PATCH to 5) or, if you intended an
unreleased/dev snapshot, document that decision and set the variable to the
exact development identifier you will use; locate the CMT_VERSION_PATCH
definition in the CMakeLists.txt (symbol: CMT_VERSION_PATCH) and adjust it to
the correct patch number or agreed-upon dev version string.
In `@lib/cmetrics/src/cmt_decode_prometheus.c`:
- Around line 546-553: The code checks only for NULL le label values but not
empty strings, so an empty le ("") slips into parse_double and produces a
generic create error; update the bucket handling in cmt_decode_prometheus.c to
treat empty le values as a syntax error by verifying
sample->label_values[le_label_index] is not NULL and not an empty string (e.g.,
string length == 0) before calling parse_double, and call report_error with
CMT_DECODE_PROMETHEUS_SYNTAX_ERROR and the existing "missing histogram bucket
\"le\" value" message when empty to keep behavior consistent with
invalid/missing boundaries.
🪄 Autofix (Beta)
Fix all unresolved CodeRabbit comments on this PR:
- Push a commit to this branch (recommended)
- Create a new PR with the fixes
ℹ️ Review info
⚙️ Run configuration
Configuration used: defaults
Review profile: CHILL
Plan: Pro
Run ID: a66f10c9-8f66-43ca-87d4-42d9a690bf46
⛔ Files ignored due to path filters (1)
lib/cmetrics/tests/prometheus_remote_write_payload.binis excluded by!**/*.bin
📒 Files selected for processing (3)
lib/cmetrics/CMakeLists.txtlib/cmetrics/src/cmt_decode_prometheus.clib/cmetrics/tests/prometheus_parser.c
| set(CMT_VERSION_MAJOR 2) | ||
| set(CMT_VERSION_MINOR 1) | ||
| set(CMT_VERSION_PATCH 1) | ||
| set(CMT_VERSION_PATCH 2) |
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🧩 Analysis chain
🌐 Web query:
What is the latest version of cmetrics library? Is version 2.1.2 available?
💡 Result:
The latest CMetrics (fluent/cmetrics) release tag is v2.0.5 (dated March 22, 2026). The repository also has an unstable tag dated April 8, 2026. [1]
Version 2.1.2 is not available in the official fluent/cmetrics tags/releases list (there is no v2.1.2 tag/release). [1]
Sources
[1] fluent/cmetrics tags (GitHub) https://github.com/fluent/cmetrics/tags
🏁 Script executed:
#!/bin/bash
# Description: Search for any hardcoded references to the old version 2.1.1
echo "=== Searching for references to version 2.1.1 ==="
rg -n "2\.1\.1" --type-add 'cmake:*.cmake' --type-add 'cmake:CMakeLists.txt' --type cmake
echo ""
echo "=== Searching for cmetrics version references in documentation ==="
rg -n "cmetrics.*2\.1\.1" --glob '*.md' --glob '*.txt' --glob '*.rst'
echo ""
echo "=== Checking git submodule configuration ==="
if [ -f .gitmodules ]; then
cat .gitmodules | grep -A 5 cmetrics
fi
echo ""
echo "=== Checking for any version pins in dependency files ==="
fd -e txt -e cmake -e conf | xargs rg -l "cmetrics" | head -20Repository: fluent/fluent-bit
Length of output: 527
Version 2.1.2 does not exist in the official cmetrics repository.
The web search confirms that the latest fluent/cmetrics release is v2.0.5 (March 22, 2026), with only an unstable tag available (April 8, 2026). There is no v2.1.2 tag or release in the official fluent/cmetrics repository.
Verify the correct version you intended to upgrade to and update the patch version accordingly. If this is targeting an unreleased development version, clarify the versioning approach with the team and update the CMakeLists.txt to reflect the actual version being used.
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@lib/cmetrics/CMakeLists.txt` at line 9, The CMake file sets CMT_VERSION_PATCH
to 2 but the official fluent/cmetrics latest release is v2.0.5, so update the
patch constant to match the real upstream tag (change CMT_VERSION_PATCH to 5)
or, if you intended an unreleased/dev snapshot, document that decision and set
the variable to the exact development identifier you will use; locate the
CMT_VERSION_PATCH definition in the CMakeLists.txt (symbol: CMT_VERSION_PATCH)
and adjust it to the correct patch number or agreed-upon dev version string.
Signed-off-by: Eduardo Silva <eduardo@chronosphere.io>
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🧹 Nitpick comments (1)
lib/cmetrics/tests/prometheus_parser.c (1)
695-713: Also validate emptylevalue in this regression test.This case verifies missing
le, but notle="". Adding the empty-value case would fully protect the new “non-emptyle” rule.Based on learnings: Applies to tests/** : Add or update tests for behavior changes, especially protocol parsing and encoder/decoder paths.✅ Suggested test extension
void test_histogram_missing_le_label() { int status; struct cmt *cmt; struct cmt_decode_prometheus_parse_opts opts; cmt = NULL; memset(&opts, 0, sizeof(opts)); status = cmt_decode_prometheus_create(&cmt, "# HELP test_histogram A histogram missing the le label.\n" "# TYPE test_histogram histogram\n" "test_histogram_bucket{foo=\"bar\"} 1\n" "test_histogram_bucket{foo=\"baz\"} 2\n" "test_histogram_sum 3.5\n" "test_histogram_count 2\n", 0, &opts); TEST_CHECK(status == CMT_DECODE_PROMETHEUS_SYNTAX_ERROR); + + if (cmt != NULL) { + cmt_decode_prometheus_destroy(cmt); + } + + cmt = NULL; + status = cmt_decode_prometheus_create(&cmt, + "# HELP test_histogram A histogram with empty le label.\n" + "# TYPE test_histogram histogram\n" + "test_histogram_bucket{le=\"\"} 1\n" + "test_histogram_sum 1\n" + "test_histogram_count 1\n", 0, &opts); + + TEST_CHECK(status == CMT_DECODE_PROMETHEUS_SYNTAX_ERROR); + + if (cmt != NULL) { + cmt_decode_prometheus_destroy(cmt); + } }🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@lib/cmetrics/tests/prometheus_parser.c` around lines 695 - 713, Extend the test_histogram_missing_le_label regression test to also cover an empty le value by invoking cmt_decode_prometheus_create with an input where the bucket lines include le="" (e.g. test_histogram_bucket{le="" ,foo="bar"} ...) and assert the same failure status CMT_DECODE_PROMETHEUS_SYNTAX_ERROR; ensure you modify the test's input string(s) or add a separate call within the same function to validate both the missing `le` and the `le=""` cases while keeping the use of opts and the final TEST_CHECK on status.
🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.
Nitpick comments:
In `@lib/cmetrics/tests/prometheus_parser.c`:
- Around line 695-713: Extend the test_histogram_missing_le_label regression
test to also cover an empty le value by invoking cmt_decode_prometheus_create
with an input where the bucket lines include le="" (e.g.
test_histogram_bucket{le="" ,foo="bar"} ...) and assert the same failure status
CMT_DECODE_PROMETHEUS_SYNTAX_ERROR; ensure you modify the test's input string(s)
or add a separate call within the same function to validate both the missing
`le` and the `le=""` cases while keeping the use of opts and the final
TEST_CHECK on status.
ℹ️ Review info
⚙️ Run configuration
Configuration used: defaults
Review profile: CHILL
Plan: Pro
Run ID: bc18b6c7-39c7-4499-abcc-7cced0b5846e
⛔ Files ignored due to path filters (1)
lib/cmetrics/tests/prometheus_remote_write_payload.binis excluded by!**/*.bin
📒 Files selected for processing (3)
lib/cmetrics/CMakeLists.txtlib/cmetrics/src/cmt_decode_prometheus.clib/cmetrics/tests/prometheus_parser.c
🚧 Files skipped from review as they are similar to previous changes (2)
- lib/cmetrics/src/cmt_decode_prometheus.c
- lib/cmetrics/CMakeLists.txt
2 participants
Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.
Summary by CodeRabbit
Bug Fixes
Tests
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