Calculate Metrics

Reports code metrics.

info

You need to configure metrics entry in the analysis_options.yaml before running this command.

To execute the command, run:

$ dcm calculate-metrics lib # or dcm cm lib

Full command description:

Usage: dcm calculate-metrics [arguments] <directories>
-h, --help                                         Print this usage information.


-r, --reporter="console" (--output-format)         Analysis output format.
                                                   [console (default), html, json, codeclimate, gitlab, checkstyle, sonar]
-o, --output-dir="OUTPUT"                          Write HTML output to OUTPUT.
                                                   (defaults to "metrics")
    --open                                         Automatically open generated HTML report.
    --flat                                         Show only a flat list of files (HTML report only).
    --output-to="path/to/file"                     Path to the file with the analysis output.
    --report-all                                   Report all metric results (default is to report only high or very high metric levels).


-c, --print-config                                 Print resolved config.


    --root-folder="./"                             Root folder.
                                                   (defaults to the current directory)
-s, --sdk-path="directory-path"                    Dart SDK directory path.
                                                   If the project has a `.fvm/flutter_sdk` symlink, it will be used if the SDK is not found.
-e, --exclude="{**/*.g.dart,**/*.freezed.dart}"    Files to exclude (in Glob syntax).
                                                   (defaults to "{**/*.g.dart,**/*.freezed.dart}")
    --root-exclude                                 Files to exclude, relative to the root folder (in Glob syntax).


    --[no-]congratulate                            Show output even when there are no issues.


    --verbose                                      Show verbose logs.


    --ci-key                                       The license key to run on CI server. Can be provided via DCM_CI_KEY env variable.
    --email                                        The email used to purchase the license. Can be provided via DCM_EMAIL env variable.


    --no-analytics                                 Disable sending anonymous usage statistics.


    --fatal-level="unset"                          Treat found equal or higher metric level as fatal (unset by default).
                                                   [near, high, very-high]

Understanding Metric Thresholds

To understand how metric thresholds work (and the available violation levels), refer to this page.

Reporting All Metric Values

By default only the HTML reporter shows all metric values (below and above) the configured thresholds.

To enable the same output for other reporters, pass the --report-all CLI flag.

Output Example

Console (default)

Use --reporter=console to get output in console format.

Console

HTML

Use --reporter=html to get output in HTML format.

info

To generate a report only for files, use the "--flat" CLI option.

HTML Report Overview

HTML

HTML Single File Report

HTML

PDF Report

To generate a PDF file from the HTML report page, use the browser ctrl+P/cmd+P menu and save the page as PDF.

JSON

Use --reporter=json to get output as a single JSON object containing metadata and the list of metric violations.

Format specification

The root object fields are

formatVersion - an integer representing the format version (will be incremented each time the serialization format changes)
timestamp - a creation time of the report in YYYY-MM-DD HH:MM:SS format
metricResults - an array of objects
summary - an array of objects

{
  "formatVersion": 10,
  "timestamp": "2021-04-11 14:44:42",
  "metricResults": [
    {
      ...
    },
    {
      ...
    },
    {
      ...
    }
  ],
  "summary": [
    {
      ...
    },
    {
      ...
    }
  ]
}

The result object fields are

path - a relative path to the target file
issues - an array of metric issues

{
  "path": "lib/src/metrics/metric_computation_result.dart",
  "issues": {
    ...
  }
}

The issue object fields are

id - metric id
message - the associated message
location - the location associated with the issue
effortInMinutes - an estimated effort to fix the issue (in minutes)
level - a level of the value computed by the metric
value - an actual value computed by the metric
unitType - a human readable unit type (optional)
declarationName - the name of the declaration (optional)
recommendation - a message with information about how the user can improve the value (optional)

{
  "id": "cyclomatic-complexity",
  "message": "This method has a cyclomatic complexity of 4, which exceeds the maximum of 3 allowed.",
  "location": {
    ...
  },
  "effortInMinutes": 15,
  "level": "high",
  "value": 4,
  "declarationName": "name"
}

The location object fields are

startColumn - the start column of the entity
startLine - the start line of the entity
endColumn - the end column of the entity
endLine - the end line of the entity
startOffset - the offset of the entity

{
  "endColumn": 2,
  "endLine": 90,
  "startColumn": 1,
  "startLine": 48,
  "startOffset": 1638
}

The summary-record object fields are

title - a message with information about the record
value - an actual value of this record (can be an array or a single value)
violations - the number of violations of a metric associated with this record

{
  "title": "Scanned folders",
  "value": 13
},
{
  "title": "Scanned files",
  "value": 30
},
{
  "title": "Scanned classes",
  "value": 71
},
{
  "title": "CYCLO",
  "value": 207,
  "violations": 0
}

Old format specification (prior to DCM 1.26.0)

The root object fields are

formatVersion - an integer representing the format version (will be incremented each time the serialization format changes)
timestamp - a creation time of the report in YYYY-MM-DD HH:MM:SS format
records - an array of objects
summary - an array of objects

{
  "formatVersion": 2,
  "timestamp": "2021-04-11 14:44:42",
  "records": [
    {
      ...
    },
    {
      ...
    },
    {
      ...
    }
  ],
  "summary": [
    {
      ...
    },
    {
      ...
    }
  ]
}

The record object fields are

path - a relative path to the target file
fileMetrics - an array with target file metrics
classes - a map with class name as the key and class report as the value
functions - a map with function name as the key and function report as the value

{
  "path": "lib/src/metrics/metric_computation_result.dart",
  "classes": {
    ...
  },
  "functions": {
    ...
  },
  "fileMetrics": {
    ...
  }
}

The summary-record object fields are

title - a message with information about the record
value - an actual value of this record (can be an array or a single value)
violations - a value of a violations count of a metric associated with this record

{
    "title": "Average Cyclomatic Number per line of code",
    "value": 0.3447098976109215,
    "violations": 5
}

The report object fields are

codeSpan - a source code span of the target entity
metrics - an array with target entity metrics

{
  "codeSpan": {
    ...
  },
  "metrics": [
    ...
  ]
}

The code span object fields are

start - a start location of an entity
end - an end location of an entity
text - a source code text of an entity

{
  "start": {
    ...
  },
  "end": {
    ...
  },
  "text": "entity source code"
}

The location object fields are

offset - a zero-based offset of the location in the source
line - a zero-based line of the location in the source
column - a zero-based column of the location in the source

{
  "offset": 156,
  "line": 7,
  "column": 1
}

The metric value object fields are

metricsId - an id of the computed metric
value - an actual value computed by the metric
unitType - a human readable unit type (optional)
level - a level of the value computed by the metric
comment - a message with information about the value
recommendation - a message with information about how the user can improve the value (optional)
context - an additional information associated with the value that helps understand how the metric was computed

{
  "metricsId": "number-of-methods",
  "value": 14,
  "unitType": "methods",
  "level": "warning",
  "comment": "This class has 14 methods, which exceeds the maximum of 10 allowed.",
  "recommendation": "Consider breaking this class up into smaller parts.",
  "context": [
    ...
  ]
}

The context message object fields are

message - an message to be displayed to the user
codeSpan - a source code span associated with or referenced by the message

{
  "message": "getter complexityEntities increase metric value",
  "codeSpan": {
    ...
  }
}

GitLab

Use --reporter=gitlab to get output in a GitLab-compatible format. To learn how to integrate DCM with GitLab, refer to this guide.

Code Climate

Use --reporter=codeclimate to get output in Code Climate format.

Output example

{"type":"issue","check_name":"widgets-nesting-level","description":"Build method has widgets nesting level of 7, which exceeds the maximum of 6 allowed.","categories":["Complexity"],"location":{"path":"lib/src/selectors/color_well.dart","positions":{"begin":{"column":3,"line":106},"end":{"column":4,"line":153}}},"severity":"info","fingerprint":"af5c0190fa59005295c7b3c6feb05547"}
{"type":"issue","check_name":"maximum-nesting-level","description":"This method has a nesting level of 2, which exceeds the maximum of 1 allowed.","categories":["Complexity"],"location":{"path":"lib/src/selectors/graphical_time_picker_painter.dart","positions":{"begin":{"column":3,"line":129},"end":{"column":4,"line":159}}},"severity":"info","fingerprint":"8b7d6bf9360ef83fe9657312127e2693"}

Checkstyle

Use --reporter=checkstyle to get output in Checkstyle format.

Output example

<?xml version="1.0"?>
<checkstyle version="10.0">
  <file name="../abstract_class.dart">
    <error line="0" message="metric comment" severity="warning" source="file-metric-id"/>
    <error line="0" severity="error" message="metric comment" source="id"/>
  </file>
  <file name="../class_with_factory_constructors.dart">
    <error line="0" severity="warning" message="metric comment" source="id"/>
  </file>
</checkstyle>

note

Checkstyle format is supported by Bitbucket. To learn how to integrate DCM with Bitbucket, refer to this guide.

Sonar

Use --reporter=sonar to get output in SonarQube's generic format for external issues.

Output example

{
  "rules": [
    {
      "cleanCodeAttribute": "CLEAR",
      "description": "To learn more, visit the documentation https://dcm.dev/docs/metrics/function/cyclomatic-complexity",
      "engineId": "dcm",
      "id": "cyclomatic-complexity",
      "impacts": [
        {
          "severity": "MEDIUM",
          "softwareQuality": "MAINTAINABILITY"
        }
      ],
      "name": "cyclomatic-complexity"
    },
    {
      "cleanCodeAttribute": "CLEAR",
      "description": "To learn more, visit the documentation https://dcm.dev/docs/metrics/function/maximum-nesting-level",
      "engineId": "dcm",
      "id": "maximum-nesting-level",
      "impacts": [
        {
          "severity": "MEDIUM",
          "softwareQuality": "MAINTAINABILITY"
        }
      ],
      "name": "maximum-nesting-level"
    },
  ],
  "issues": [
    {
      "primaryLocation": {
        "filePath": "lib/src/sheets/macos_sheet.dart",
        "message": "This method has a cyclomatic complexity of 4, which exceeds the maximum of 2 allowed.",
        "textRange": {
          "endColumn": 4,
          "endLine": 101,
          "startColumn": 3,
          "startLine": 52
        }
      },
      "ruleId": "cyclomatic-complexity"
    },
    {
      "effortMinutes": 10,
      "primaryLocation": {
        "filePath": "lib/src/sheets/macos_sheet.dart",
        "message": "This method has a nesting level of 2, which exceeds the maximum of 1 allowed.",
        "textRange": {
          "endColumn": 4,
          "endLine": 210,
          "startColumn": 3,
          "startLine": 182
        }
      },
      "ruleId": "maximum-nesting-level"
    },
  ],
}

Understanding Metric Thresholds​

Reporting All Metric Values​

Output Example​

Console (default)​

HTML​

HTML Report Overview​

HTML Single File Report​

PDF Report​

JSON​

The root object fields are​

The result object fields are​

The issue object fields are​

The location object fields are​

The summary-record object fields are​

The root object fields are​

The record object fields are​

The summary-record object fields are​

The report object fields are​

The code span object fields are​

The location object fields are​

The metric value object fields are​

The context message object fields are​

GitLab​

Code Climate​

Checkstyle​

Sonar​

Understanding Metric Thresholds

Reporting All Metric Values

Output Example

Console (default)

HTML

HTML Report Overview

HTML Single File Report

PDF Report

JSON

The root object fields are

The result object fields are

The issue object fields are

The location object fields are

The summary-record object fields are

The root object fields are

The record object fields are

The summary-record object fields are

The report object fields are

The code span object fields are

The location object fields are

The metric value object fields are

The context message object fields are

GitLab

Code Climate

Checkstyle

Sonar