53 lines
2.3 KiB
Markdown
53 lines
2.3 KiB
Markdown
# procfs
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This procfs package provides functions to retrieve system, kernel and process
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metrics from the pseudo-filesystems /proc and /sys.
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*WARNING*: This package is a work in progress. Its API may still break in
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backwards-incompatible ways without warnings. Use it at your own risk.
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[](https://godoc.org/github.com/prometheus/procfs)
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[](https://travis-ci.org/prometheus/procfs)
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[](https://goreportcard.com/report/github.com/prometheus/procfs)
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## Usage
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The procfs library is organized by packages based on whether the gathered data is coming from
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/proc, /sys, or both. Each package contains an `FS` type which represents the path to either /proc, /sys, or both. For example, current cpu statistics are gathered from
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`/proc/stat` and are available via the root procfs package. First, the proc filesystem mount
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point is initialized, and then the stat information is read.
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```go
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fs, err := procfs.NewFS("/proc")
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stats, err := fs.Stat()
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```
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Some sub-packages such as `blockdevice`, require access to both the proc and sys filesystems.
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```go
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fs, err := blockdevice.NewFS("/proc", "/sys")
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stats, err := fs.ProcDiskstats()
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```
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## Building and Testing
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The procfs library is normally built as part of another application. However, when making
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changes to the library, the `make test` command can be used to run the API test suite.
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### Updating Test Fixtures
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The procfs library includes a set of test fixtures which include many example files from
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the `/proc` and `/sys` filesystems. These fixtures are included as a [ttar](https://github.com/ideaship/ttar) file
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which is extracted automatically during testing. To add/update the test fixtures, first
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ensure the `fixtures` directory is up to date by removing the existing directory and then
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extracting the ttar file using `make fixtures/.unpacked` or just `make test`.
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```bash
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rm -rf fixtures
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make test
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```
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Next, make the required changes to the extracted files in the `fixtures` directory. When
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the changes are complete, run `make update_fixtures` to create a new `fixtures.ttar` file
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based on the updated `fixtures` directory. And finally, verify the changes using
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`git diff fixtures.ttar`.
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