Adds a flag to the cli to override the entrypoint of a custom docker image. It could be used to reuse existing images with different eentrypoints.

Signed-off-by: Carlo Colombo <carlo.colombo@klarna.com>

.changeset/techdocs-fresh-panthers-kick.md

@@ -0,0 +1,5 @@
+---
+'@techdocs/cli': patch
+---
+
+Adds a new flag to override the entrypoint when using a custom docker image. It could be used to reuse existing images with different entrypoints.

docs/features/techdocs/cli.md

@@ -71,7 +71,7 @@ implementation, which uses the MkDocs preview server as a proxy to fetch the
 generated documentation files and assets.
 
 NOTE: When using a custom `techdocs` docker image, make sure the entry point is
-also `ENTRYPOINT ["mkdocs"]`.
+also `ENTRYPOINT ["mkdocs"]` or override with `--docker-entrypoint`.
 
 Command reference:
 
@@ -81,11 +81,12 @@ Usage: techdocs-cli serve [options]
 Serve a documentation project locally in a Backstage app-like environment
 
 Options:
-  -i, --docker-image <DOCKER_IMAGE>  The mkdocs docker container to use (default: "spotify/techdocs")
-  --no-docker                        Do not use Docker, use MkDocs executable in current user environment.
-  --mkdocs-port <PORT>               Port for MkDocs server to use (default: "8000")
-  -v --verbose                       Enable verbose output. (default: false)
-  -h, --help                         display help for command
+  -i, --docker-image <DOCKER_IMAGE>        The mkdocs docker container to use (default: "spotify/techdocs")
+  --docker-entrypoint <DOCKER_ENTRYPOINT>  Override the image entrypoint
+  --no-docker                              Do not use Docker, use MkDocs executable in current user environment.
+  --mkdocs-port <PORT>                     Port for MkDocs server to use (default: "8000")
+  -v --verbose                             Enable verbose output. (default: false)
+  -h, --help                               display help for command
 ```
 
 ### Generate TechDocs site from a documentation project

packages/techdocs-cli/src/commands/index.ts

@@ -206,6 +206,10 @@ export function registerCommands(program: CommanderStatic) {
       'The mkdocs docker container to use',
       defaultDockerImage,
     )
+    .option(
+      '--docker-entrypoint <DOCKER_ENTRYPOINT>',
+      'Override the image entrypoint',
+    )
     .option(
       '--no-docker',
       'Do not use Docker, run `mkdocs serve` in current user environment.',
@@ -224,6 +228,10 @@ export function registerCommands(program: CommanderStatic) {
       'The mkdocs docker container to use',
       defaultDockerImage,
     )
+    .option(
+      '--docker-entrypoint <DOCKER_ENTRYPOINT>',
+      'Override the image entrypoint',
+    )
     .option(
       '--no-docker',
       'Do not use Docker, use MkDocs executable in current user environment.',

packages/techdocs-cli/src/commands/serve/mkdocs.ts

@@ -61,6 +61,7 @@ export default async function serveMkdocs(cmd: Command) {
   const childProcess = await runMkdocsServer({
     port: cmd.port,
     dockerImage: cmd.dockerImage,
+    dockerEntrypoint: cmd.dockerEntrypoint,
     useDocker: cmd.docker,
     stdoutLogFunc: logFunc,
     stderrLogFunc: logFunc,

packages/techdocs-cli/src/commands/serve/serve.ts

@@ -90,6 +90,7 @@ export default async function serve(cmd: Command) {
   const mkdocsChildProcess = await runMkdocsServer({
     port: cmd.mkdocsPort,
     dockerImage: cmd.dockerImage,
+    dockerEntrypoint: cmd.dockerEntrypoint,
     useDocker: cmd.docker,
     stdoutLogFunc: mkdocsLogFunc,
     stderrLogFunc: mkdocsLogFunc,

packages/techdocs-cli/src/lib/mkdocsServer.ts

@@ -21,6 +21,7 @@ export const runMkdocsServer = async (options: {
   port?: string;
   useDocker?: boolean;
   dockerImage?: string;
+  dockerEntrypoint?: string;
   stdoutLogFunc?: LogFunc;
   stderrLogFunc?: LogFunc;
 }): Promise<ChildProcess> => {
@@ -41,6 +42,9 @@ export const runMkdocsServer = async (options: {
         '-p',
         `${port}:${port}`,
         '-it',
+        ...(options.dockerEntrypoint
+          ? ['--entrypoint', options.dockerEntrypoint]
+          : []),
         dockerImage,
         'serve',
         '--dev-addr',