grim/convey

Add basic templating for the kubectl commands

2018-02-20, Gary Kramlich
47df081c14f8
Parents 8c7af5e9a4cc
Children bbf13b21ba8d
Add basic templating for the kubectl commands
5 files changed, 100 insertions(+), 23 deletions(-)
  • +8 -1
    kubectl/README.md
  • +1 -0
    kubectl/apply.go
  • +89 -22
    kubectl/command.go
  • +1 -0
    kubectl/create.go
  • +1 -0
    kubectl/delete.go
    • --- a/kubectl/README.md Mon Feb 19 17:04:37 2018 -0600
    +++ b/kubectl/README.md Tue Feb 20 16:43:51 2018 -0600
    @@ -1,7 +1,11 @@
    # kubectl
    The kubectl package provides tasks for interacting with kubernetes via kubectl.
    -It supplies the create, apply, and delete commands.
    +It supplies the create, apply, and delete commands. It provides a few
    +templating engines that can be used to template your manifests before they're
    +used.
    +
    +If `none` or no engine is specified then no templating is done. An engine of `environment` will do normal variable swapping with the environment variables that convey knows about in the format of `${VARNAME}` or `$VARNAME`.
    ----
    @@ -17,6 +21,7 @@
    | files | Yes | | The list of manifest files to apply. |
    | namespace | | | The kubernetes namespace to use. |
    | selector | | | The selector to use. |
    +| engine | | | The template engine to use. |
    ### Example
    @@ -39,6 +44,7 @@
    | files | Yes | | The list of manifest files to apply. |
    | namespace | | | The kubernetes namespace to use. |
    | selector | | | The selector to use. |
    +| engine | | | The template engine to use. |
    ### Example
    @@ -61,6 +67,7 @@
    | files | Yes | | The list of manifest files to apply. |
    | namespace | | | The kubernetes namespace to use. |
    | selector | | | The selector to use. |
    +| engine | | | The template engine to use. |
    ### Example
    --- a/kubectl/apply.go Mon Feb 19 17:04:37 2018 -0600
    +++ b/kubectl/apply.go Tue Feb 20 16:43:51 2018 -0600
    @@ -33,6 +33,7 @@
    Namespace: a.Namespace,
    Files: a.Files,
    Selector: a.Selector,
    + Engine: a.Engine,
    }
    return cmd.Execute(name, "apply", logger, env, st)
    --- a/kubectl/command.go Mon Feb 19 17:04:37 2018 -0600
    +++ b/kubectl/command.go Tue Feb 20 16:43:51 2018 -0600
    @@ -17,6 +17,7 @@
    package kubectl
    import (
    + "io/ioutil"
    "path/filepath"
    "github.com/aphistic/gomol"
    @@ -34,6 +35,83 @@
    Namespace string `yaml:"namespace"`
    Files yaml.StringOrSlice `yaml:"files"`
    Selector string `yaml:"selector"`
    + Engine string `yaml:"engine"`
    +}
    +
    +// templateNone just copies files from the workspace into the scratch directory.
    +func (c *CRUDCommand) templateNone(name, scratchDir string, cmd *command.Generator, logger *gomol.LogAdapter, env []string, st *state.State) error {
    + // update the files we're going to run by joining them with our scratch directory
    + for _, file := range c.Files {
    + realFile, err := environment.Mapper(file, env)
    + if err != nil {
    + return err
    + }
    +
    + cmd.Append("-f", filepath.Join(scratchDir, realFile))
    + }
    +
    + // now create an export task to get our files out of the workspace
    + export := &docker.Export{
    + Files: c.Files,
    + Path: scratchDir,
    + }
    +
    + // make sure the export task is valid
    + err := export.Valid()
    + if err != nil {
    + return err
    + }
    +
    + // run the export
    + err = export.Execute(name, logger, env, st)
    + if err != nil {
    + return err
    + }
    +
    + return nil
    +}
    +
    +// templateEnvironment will copy files from the workspace into the scratch
    +// directory and replace environment variables with those that convey knows
    +// about.
    +func (c *CRUDCommand) templateEnvironment(name, scratchDir string, cmd *command.Generator, logger *gomol.LogAdapter, env []string, st *state.State) error {
    + // run the normal export which we will update in place.
    + err := c.templateNone(name, scratchDir, cmd, logger, env, st)
    + if err != nil {
    + return err
    + }
    +
    + // now iterate the files and replace all their environment variables with those that we have
    + for _, file := range c.Files {
    + // resolve the filename if it's templated
    + resolvedFile, err := environment.Mapper(file, env)
    + if err != nil {
    + return err
    + }
    +
    + // figure out the full path to it
    + absFile := filepath.Join(scratchDir, resolvedFile)
    +
    + // read the file
    + raw, err := ioutil.ReadFile(absFile)
    + if err != nil {
    + return err
    + }
    +
    + // replace the environment variables in it
    + data, err := environment.Mapper(string(raw), env)
    + if err != nil {
    + return err
    + }
    +
    + // write the templated data back out
    + err = ioutil.WriteFile(absFile, []byte(data), 0700)
    + if err != nil {
    + return err
    + }
    + }
    +
    + return nil
    }
    // Execute runs the given `kubectl` command with the given arguments.
    @@ -75,30 +153,19 @@
    return err
    }
    - // update the files we're going to run by joining them with our scratch directory
    - for _, file := range c.Files {
    - realFile, err := environment.Mapper(file, fullEnv)
    - if err != nil {
    - return err
    - }
    -
    - cmd.Append("-f", filepath.Join(path, realFile))
    + // run our files through the template engine
    + switch c.Engine {
    + case "":
    + fallthrough
    + case "none":
    + err = c.templateNone(name, path, cmd, logger, fullEnv, st)
    + case "env":
    + fallthrough
    + case "environment":
    + err = c.templateEnvironment(name, path, cmd, logger, fullEnv, st)
    }
    - // now create an export task to get our files out of the workspace
    - export := &docker.Export{
    - Files: c.Files,
    - Path: path,
    - }
    -
    - // make sure the export task is valid
    - err = export.Valid()
    - if err != nil {
    - return err
    - }
    -
    - // run the export
    - err = export.Execute(name, logger, env, st)
    + // if there was an error with templating bail
    if err != nil {
    return err
    }
    --- a/kubectl/create.go Mon Feb 19 17:04:37 2018 -0600
    +++ b/kubectl/create.go Tue Feb 20 16:43:51 2018 -0600
    @@ -33,6 +33,7 @@
    Namespace: c.Namespace,
    Files: c.Files,
    Selector: c.Selector,
    + Engine: c.Engine,
    }
    return cmd.Execute(name, "create", logger, env, st)
    --- a/kubectl/delete.go Mon Feb 19 17:04:37 2018 -0600
    +++ b/kubectl/delete.go Tue Feb 20 16:43:51 2018 -0600
    @@ -33,6 +33,7 @@
    Namespace: d.Namespace,
    Files: d.Files,
    Selector: d.Selector,
    + Engine: d.Engine,
    }
    return cmd.Execute(name, "delete", logger, env, st)