Month: April 2020

Go: Build-Time Variables

Go allows you to override global variables at build time during the linker stage:

$ go build -o /tmp/prog-custom -ldflags "-X main.overrideableValuePhrase=123456" ./cmd/prog

Requirements:

  • It must be a global variable and not a constant.
  • It might be in the package that you are telling it to build. This definitely works for executables and, with the removal of support for binary-only packages (BOPs), it probably doesn’t apply whatsoever to intermediate packages.
  • It must be a string (so, process it from the init() function).

It doesn’t matter whether it is an exported or unexported symbol.

 

Git: Use git-sizer to Identify Large Space Usage in Your History

https://github.com/github/git-sizer

Notice that it cites the revisions at the bottom:

$ git-sizer -v
Processing blobs: 2049                        
Processing trees: 1056                        
Processing commits: 432                        
Matching commits to trees: 432                        
Processing annotated tags: 0                        
Processing references: 12                        
| Name                         | Value     | Level of concern               |
| ---------------------------- | --------- | ------------------------------ |
| Overall repository size      |           |                                |
| * Commits                    |           |                                |
|   * Count                    |   432     |                                |
|   * Total size               |   143 KiB |                                |
| * Trees                      |           |                                |
|   * Count                    |  1.06 k   |                                |
|   * Total size               |   885 KiB |                                |
|   * Total tree entries       |  21.0 k   |                                |
| * Blobs                      |           |                                |
|   * Count                    |  2.05 k   |                                |
|   * Total size               |  33.8 MiB |                                |
| * Annotated tags             |           |                                |
|   * Count                    |     0     |                                |
| * References                 |           |                                |
|   * Count                    |    12     |                                |
|                              |           |                                |
| Biggest objects              |           |                                |
| * Commits                    |           |                                |
|   * Maximum size         [1] |  1.32 KiB |                                |
|   * Maximum parents      [2] |     2     |                                |
| * Trees                      |           |                                |
|   * Maximum entries      [3] |    66     |                                |
| * Blobs                      |           |                                |
|   * Maximum size         [4] |  4.05 MiB |                                |
|                              |           |                                |
| History structure            |           |                                |
| * Maximum history depth      |   413     |                                |
| * Maximum tag depth          |     0     |                                |
|                              |           |                                |
| Biggest checkouts            |           |                                |
| * Number of directories  [5] |    27     |                                |
| * Maximum path depth     [6] |     4     |                                |
| * Maximum path length    [7] |   105 B   | *                              |
| * Number of files        [6] |   137     |                                |
| * Total size of files    [8] |  4.64 MiB |                                |
| * Number of symlinks         |     0     |                                |
| * Number of submodules       |     0     |                                |

[1]  a52f2b2c86baa9617ed66bc0b3301d57bf763ed3
[2]  fa562d025143096dc8ae0c2294114cd0b4443945 (refs/stash)
[3]  4ca9fdb84fec68c38d6061441996fd15b9494e9d (d2a75bc4b9743a3decf9e6cd5cb4a8670d57f30d^{tree})
[4]  62918aac7359d32b4b342db8d65a5a2a5172215d (86c3344be1fc590ee3ebe9eb7117e91c4ad21450:command/gozipinfo/gozipinfo)
[5]  2b5b648f5e6488420c22ba9c318fc6bfc4ce2a47 (461bbd7555360a202d1ab16f02c992581791a7d2^{tree})
[6]  853678df5f5fe5ec58b169d0fe3878e376c53e3e (refs/heads/dustin/profiling/temp_path^{tree})
[7]  8b03f6bab9d3369fec1fe322f5d3f159a220d95a (1b385e1714b7904fca85943d0f27c7f772af6d0f^{tree})
[8]  a557ab9aff02167856530cf536163d349e44fdfe (86c3344be1fc590ee3ebe9eb7117e91c4ad21450^{tree})