Update docs and tweak error messages.

This commit is contained in:
Eric Huss 2020-04-21 15:34:59 -07:00
parent 6b550cb4bb
commit 2732c5e8f7
3 changed files with 18 additions and 10 deletions

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@ -331,7 +331,7 @@ the usual `RUST_LOG` to control logging verbosity.
## Handling missing backends
If you should enable a backend that isn't installed, the default behavior is to throw an error:
If you enable a backend that isn't installed, the default behavior is to throw an error:
```text
The command wasn't found, is the "wordcount" backend installed?

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@ -306,11 +306,17 @@ specify which preprocessors should run before the Markdown renderer.
A custom renderer can be enabled by adding a `[output.foo]` table to your
`book.toml`. Similar to [preprocessors](#configuring-preprocessors) this will
instruct `mdbook` to pass a representation of the book to `mdbook-foo` for
rendering.
rendering. See the [alternative backends] chapter for more detail.
Custom renderers will have access to all configuration within their table
(i.e. anything under `[output.foo]`), and the command to be invoked can be
manually specified with the `command` field.
The custom renderer has access to all the fields within its table (i.e.
anything under `[output.foo]`). mdBook checks for two common fields:
- **command:** The command to execute for this custom renderer. Defaults to
the name of the renderer with the `mdbook-` prefix (such as `mdbook-foo`).
- **optional:** If `true`, then the command will be ignored if it is not
installed, otherwise mdBook will fail with an error. Defaults to `false`.
[alternative backends]: ../for_developers/backends.md
## Environment Variables

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@ -166,15 +166,17 @@ impl CmdRenderer {
};
if is_optional {
warn!("The command was not found, but was marked as optional.");
warn!("\tCommand: {}", self.cmd);
warn!(
"The command `{}` for backend `{}` was not found, \
but was marked as optional.",
self.cmd, self.name
);
return Ok(());
} else {
error!(
"The command wasn't found, is the \"{}\" backend installed?",
self.name
"The command `{}` wasn't found, is the `{}` backend installed?",
self.cmd, self.name
);
error!("\tCommand: {}", self.cmd);
}
}
_ => {}