gosloc

gosloc is a "lines of code" counter for Golang. It produces output like this:

$ gosloc github.com/lib/pq/
Scanned 40 go files in github.com/lib/pq/:
  Source lines:    5143 (75.2%)
  Comment lines:   908 (13.3%)
  Blank lines:     784 (11.5%)
  Test lines:      5496 (1.07 per line of code)
  Total file size: 0.32 Mb

The tool is not meant to be 100% precise (see details below) but instead to give you a general idea of how much code there is in a particular project, and compare the size of the code to the size of the source code documentation and test suite.

These attributes are useful to know when you are auditing a codebase, either for security purposes or before deciding to use it. Most code bases tend to grow over time as features are added, but smaller code bases are usually easier to maintain.

For example, we can compare three popular PostgreSQL libraries for Go using this tool:

$ gosloc github.com/go-pg/pg/
Scanned 144 go files in github.com/go-pg/pg/:
  Source lines:    13170 (81.2%)
  Comment lines:   568 (3.5%)
  Blank lines:     2486 (15.3%)
  Test lines:      8005 (0.61 per line of code)
  Total file size: 0.54 Mb
$ gosloc github.com/jackc/pgx/
Scanned 251 go files in github.com/jackc/pgx/:
  Source lines:    22145 (79.4%)
  Comment lines:   1356 (4.9%)
  Blank lines:     4396 (15.8%)
  Test lines:      16911 (0.76 per line of code)
  Total file size: 1.12 Mb
$ gosloc github.com/lib/pq/
Scanned 40 go files in github.com/lib/pq/:
  Source lines:    5143 (75.2%)
  Comment lines:   908 (13.3%)
  Blank lines:     784 (11.5%)
  Test lines:      5496 (1.07 per line of code)
  Total file size: 0.32 Mb

From this we can see that lib/pq has the highest ratio of tests and comments, as well as the smallest overall code size, so (based on these entirely arbitrary criteria) this might be a good place to start.

Caveats / Notes

• Only .go files are included.

• vendor folders are excluded by default. You can include them with -vendor.

• testdata folders are excluded.

• Files generated by go-bindata are skipped. The tool will tell you when this happens.

• Files with particularly long lines (like those generated by tools similar to go-bindata) are also skipped. The tool will tell you when this happens.

• Go allows inline comments after a statement. These are counted as code lines, not comment lines.

• Comments in the form of /**/ are currently counted as code. This is a bug.

• Comments and blank lines in test files (ending in _test.go) are not counted.

• Vendoring tools often omit tests so this will skew the test ratio.

• The percentage scores (source, comment, blank) are calculated for source files only (tests are excluded).

Other Tools

Other Go tools for static analysis.

• golint
• gocyclo
• ineffassign
• deadcode
• gometalinter
• gometalinter linter list
• golangci-lint
• list of static analysis tools
• Article discussing some of these tools

There are many other resources and this list is just here to get you started. Thanks to Go's 1.0 compatibility promise, many static analysis tools continue to work even if they are a bit out of date.