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diff --git a/docs/_posts/2022-05-01-regex101-integration.md b/docs/_posts/2022-05-01-regex101-integration.md new file mode 100644 index 0000000..02011ce --- /dev/null +++ b/docs/_posts/2022-05-01-regex101-integration.md @@ -0,0 +1,73 @@ +--- +layout: post +title: Integration with regex101.com +excerpt: Create/edit format files using regex101.com +--- + +*(This change will be in the upcoming v0.11.0 release)* + +Creating and updating format files for **lnav** can be a bit tedious and +error-prone. To help streamline the process, an integration with regex101.com +has been added. Now, you can create regular expressions for plaintext log +files on https://regex101.com and then create a skeleton format file with a +simple command. If you already have a format file that needs to be updated, +you can push the regexes up to regex101, edit them with their interface, and +then pull the changes back down as a format patch file. + +To further improve the experience of developing with format files, there is +also work underway to improve error messages. Many messages should be clearer, +more context is provided, and they should look nicer as well. For example, the +following error is displayed when a format regex is not valid: + + + +## Management CLI + +The regex101 integration can be accessed through the new "management-mode CLI". +This mode can be accessed by passing `-m` as the first option to **lnav**. The +management CLI is organized as a series of nested commands. If you're not sure +what to do at a given level, run the command as-is and the CLI should print out +help text to guide you through the hierarchy of commands and required +parameters. + +### Create a format from a regular expression + +The `regex101 import` command can be used to import a regular expression from +regex101.com and create or patch a format file. The command takes the URL of +the regex, the format name, and the name of the regex in the log format ( +defaults to "std" if not given). For example, the following command can be used +to import the regex at "https://regex101.com/r/zpEnjV/2" into the format named " +re101_example_log": + +```console +$ lnav -m regex101 import https://regex101.com/r/zpEnjV/2 re101_example_log +``` + +If the import was successful, the path to the skeleton format file will be +printed. You will most likely need to edit the file to fill in more details +about your log format. + +### Editing an existing regular expression + +If you have a log format with a regex that needs to be updated, you can push +the regex to regex101.com for editing with a command like (replace +"myformat_log"/"std" with the name of your format and regex): + +```console +$ lnav -m format myformat_log regex std regex101 push +``` + +Along with the regex, the format's samples will be added to the entry to ensure +changes won't break existing matches. If the push was successful, the URL for +the new regex101.com entry will be printed out. You can use that URL to edit the +regex to your needs. Once you're done editing the regex, you can pull the +changes down to a "patch" file using the following command: + +```console +$ lnav -m format myformat_log regex std regex101 pull +``` + +The patch file will be evaluated after the original format file and override +the values from the original. Once you are satisfied with the changes, you +can move the contents of the patch file to the original file and delete the +patch. |