435c0d9fc8
This PR switches the Nomad repository from using govendor to Go modules for managing dependencies. Aspects of the Nomad workflow remain pretty much the same. The usual Makefile targets should continue to work as they always did. The API submodule simply defers to the parent Nomad version on the repository, keeping the semantics of API versioning that currently exists.
62 lines
2.7 KiB
Markdown
62 lines
2.7 KiB
Markdown
# procfs
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This 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,
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/sys, or both. For example, 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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## Package Organization
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The packages in this project are organized according to (1) whether the data comes from the `/proc` or
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`/sys` filesystem and (2) the type of information being retrieved. For example, most process information
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can be gathered from the functions in the root `procfs` package. Information about block devices such as disk drives
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is available in the `blockdevices` sub-package.
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## Building and Testing
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The procfs library is intended to be built as part of another application, so there are no distributable binaries.
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However, most of the API includes unit tests which can be run with `make test`.
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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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