CI Failure Log Analyzer

A failed continuous integration run is rarely explained by the final red badge alone. The job log is the transcript of setup, checkout, dependency installation, build commands, tests, uploads, deployment steps, and runner cleanup. The line that says exit code 1 confirms that a command returned failure, but the line worth fixing is often earlier: the first assertion error, missing module, refused token, timed-out service, or runner resource warning.

CI triage is the work of separating a useful clue from noise. Logs often mix several kinds of messages: command echoes, section markers, warnings, retries, duration summaries, test output, and post-job cleanup. A warning near the top of a log may be unrelated to the red job, while a short error buried before a long stack trace may name the real file, registry, secret, or service that needs attention.

Several terms make CI logs easier to read. A workflow or pipeline groups work for a branch, pull request, release, or scheduled check. A job runs on a runner or agent. A step is one command or action inside that job. A stage is a broader phase such as dependencies, build, test, lint, artifact handling, or deploy. Good incident notes preserve those boundaries because a failed test, a missing cache artifact, and a runner disk problem require different owners.

A concise CI failure note should include the first meaningful line number, stage, failure class, evidence snippet, and the next check. That note is safer and more useful than pasting an entire job log into a chat thread, especially when logs may contain private hostnames, branch names, tokens, customer identifiers, or deployment details.

How to Use This Tool:

Analyze one failed job or one focused failing excerpt at a time. A small section around the failing command usually produces cleaner clues than a full workflow archive with unrelated jobs.

1. Paste text into CI job log, drop a .log or .txt file onto the textarea, choose Browse LOG, or load Sample to see the expected result shape.
2. Use Normalize when copied terminal output contains color codes, mixed line endings, or trailing spaces. The cleaned text keeps line order so the output can still point back to useful line numbers.
3. Start with CI provider profile set to Auto detect. Force GitHub Actions, GitLab CI, CircleCI, Jenkins, or Generic shell log when the provider badge looks wrong or the excerpt no longer includes provider markers.
4. Set Slow step threshold to the duration that deserves review for this repository. Enter 0 only when every parsed duration should become a slow-step signal.
5. Open Advanced for a pipeline label, custom failure phrases, neighboring Context lines, Maximum signals, or the Mask secret-like values switch.
6. If the attention message asks for a log, restore pasted text or load a file. If the output becomes noisy, remove broad custom terms and use a smaller Maximum signals value for the first review pass.
7. Read Failure Signals first, compare Stage Ledger for affected phases, then use Triage Actions for the next owner check. Open CI Stage Signal Stack when a visual split by stage helps with handoff.

Before sharing results, copy only the rows that support the next action and review masked snippets for leftover sensitive values.

Interpreting Results:

The summary count is a count of matched signals, not a count of proven root causes. Critical means the log matched severe families such as memory pressure, timeout, credentials, or runner infrastructure. Failure covers job-breaking classes such as test, compile, dependency, network, artifact, lint, deployment, and nonzero command exits. Warning and Slow are review clues that need nearby context.

Failure Signals is ranked by severity before line number. The top row can be more severe than the earliest row, so confirm both the highest-severity clue and the earliest related clue in the same stage. A later exit-code footer is often less useful than the first file-level diagnostic, failed assertion, or denied credential message.

• Stage is inferred from headings, command text, section markers, and nearby lines. Verify it against the raw CI view when a copied excerpt removed boundaries.
• Confidence describes how specific the detector family is. It does not measure business impact or prove the exact commit that caused the failure.
• Stage Ledger groups failures, warnings, and slow steps by phase. It is useful for routing, but line order still matters when one early failure causes later errors.
• Slow step rows need a baseline. A 90-second install can be ordinary in one project and a warning sign in another.

No failure signal means the pasted text did not match the known patterns. It does not prove the job succeeded; inspect the raw log around the failed step, final status, and provider summary before closing the incident.

Technical Details:

CI log triage begins by turning copied console output into stable plain text. Terminal escape sequences are removed, carriage returns are normalized to newline characters, and trailing spaces are trimmed. Line order remains unchanged, which makes line-number evidence usable after pasting from a browser, terminal, downloaded log, or local text file.

Provider and stage recognition depend on visible grammar in the log. GitHub Actions commonly exposes grouped step markers and exit-code wording, GitLab CI can include section markers and job log timestamps, CircleCI logs are organized around jobs and steps, and Jenkins pipelines may show stage text from pipeline views. When those markers are missing, the analysis falls back to command words and keeps unmatched material in an unclassified stage.

Rule Core

The analyzer is a rule-based classifier, not a statistical predictor. It matches known CI failure wording, suppresses obvious success summaries such as 0 failed and exit code 0, ranks stronger signals first, and keeps warning or duration clues as supporting evidence.

Stage and Boundary Rules

Stage assignment uses explicit headings first, then command and log text. Checkout, dependencies, build, test, lint, container, artifact, deploy, runner infrastructure, and unclassified work are separate because they route to different first checks. A test-stage credential error can still be a credential problem, so the failure class and stage should be read together.

Duration parsing accepts direct units such as milliseconds, seconds, and minutes, as well as clock-like values when the surrounding line names time, elapsed, runtime, duration, took, or finished. A slow signal is added only when the parsed value meets the selected threshold. The same log and settings produce the same results, so repeated runs are comparable when the pasted text, provider profile, slow threshold, context radius, signal cap, custom terms, and masking choice stay the same.

The analysis does not fetch provider data, inspect commit history, read test reports, or determine the responsible code change. It converts the text provided on the page into ranked failure signals, stage counts, suggested triage actions, a stage signal chart, and structured evidence for a human review.

Privacy Notes:

The pasted log and selected local file are analyzed in the browser. The page does not connect to GitHub Actions, GitLab CI, CircleCI, Jenkins, or another provider to fetch logs, but copied rows and downloaded evidence can still contain sensitive information.

• Keep Mask secret-like values on before sharing CSV, DOCX, JSON, chart images, or screenshots outside the build team.
• Review snippets manually when logs may contain private hostnames, account IDs, customer data, deployment targets, or issue links.
• Prefer a focused failing excerpt when the full job log contains unrelated credentials or release details.

Advanced Tips:

• Keep CI provider profile on Auto detect for complete logs, but force the provider when a copied excerpt has lost grouped step markers, section markers, or Jenkins stage text.
• Use narrow Extra failure terms such as contract check failed instead of broad words such as failed. Broad terms can make ordinary summaries and unrelated warnings look like failure rows.
• Set Context lines to 0 when you need a minimal handoff, and raise it only when the neighboring command or stack frame changes the next action.
• Raise Maximum signals for early exploration, then lower it before exporting so CSV, DOCX, and JSON evidence focus on the rows a reviewer actually needs.
• Compare Slow step threshold against recent successful runs from the same repository. A duration is more useful when it shows drift, not merely when it is large in isolation.
• Open CI Stage Signal Stack when the incident needs routing across teams. A stage with many warnings but no failure can still be secondary if a more severe failure appears earlier in another phase.
• Leave Mask secret-like values enabled for shared evidence, then manually review snippets that may still contain private hostnames, account IDs, customer identifiers, or internal URLs.

Worked Examples:

Test failure before the footer

A GitHub Actions excerpt includes FAIL tests/payment/refund.spec.ts, Expected status 200, received 500, and a later Process completed with exit code 1. Failure Signals reports a test failure with the original line number, while Triage Actions recommends opening the first failing test and rerunning the narrow target. The footer confirms the job failed, but the test line is the stronger starting point.

Dependency error that looks like a build failure

A log shows npm ERR! and a lockfile conflict during installation, then the build step never runs. Stage Ledger places the top clue in dependencies, and Triage Actions points toward lockfile drift, registry reachability, package cache state, and runtime version. Changing compile flags would not address that failure path.

Slow deploy near a timeout

A GitLab CI deploy command reports duration=290s and later times out. With Slow step threshold set to 300, the timeout is critical but the 290-second duration is not listed as slow. Lowering the threshold to 240 adds a slow-step row, and CI Stage Signal Stack shows both clues in the deploy stage.

Custom term that creates noise

A team adds failed in Extra failure terms and the ledger fills with generic lines. Replacing it with contract check failed keeps Failure Signals focused on the team-specific failure phrase. Custom terms work best when they are narrow enough to avoid success summaries, warnings, and unrelated package text.

FAQ:

Glossary:

Failure signal

A matched line, duration, or custom phrase that suggests a failed command, warning, slow step, or review clue.

Stage

The inferred CI phase, such as dependencies, build, test, lint, artifact handling, deploy, runner infrastructure, or unclassified work.

Provider profile

The CI log grammar used to recognize provider markers and section hints.

Context lines

Neighboring lines copied around a signal so a reviewer can check the clue without sharing the full log.

Triage action

A suggested next check based on the strongest matching failure family and affected stage.

References:

• Using workflow run logs, GitHub Docs.
• CI/CD job logs, GitLab Docs.
• Jobs and steps, CircleCI Docs.
• Running Pipelines, Jenkins documentation.
• How to check authentication logs in Linux, Simplified Guide.
• How to run Playwright tests in a Docker container, Simplified Guide.