feat(install_cloud_clis): lazy-load and cache bash completions

changelogs/fragments/lazy-load-bash-completions.yml

@@ -0,0 +1,3 @@
+---
+minor_changes:
+  - install_cloud_clis - lazy-load and cache bash completions to eliminate subprocess spawns at shell startup

roles/install_cloud_clis/README.md

@@ -87,7 +87,7 @@ When `install_cloud_clis_manage_bashrc_completion` is `true`, the role writes on
 
 `# BEGIN ANSIBLE MANAGED BLOCK branic.system_management.install_cloud_clis` and `# END ANSIBLE MANAGED BLOCK branic.system_management.install_cloud_clis`
 
-The block uses **`if command -v …; then` / `fi`** stanzas and `# shellcheck source=/dev/null` before `source <(…)` completions, matching common interactive shell style. Only CLIs listed in `install_cloud_clis_components` are included, in the same order as `install_cloud_clis_cli_installers` in [`vars/main.yml`](vars/main.yml).
+The block defines a **`_lazy_completion`** shell function and registers one-liner calls for each CLI. Completions are deferred until the user's first tab-complete for a given command, then cached under **`~/.cache/bash_completions/`**. The cache auto-invalidates when the CLI binary is newer than the cached file. AWS CLI uses a direct binary completer (`aws_completer`) and does not use the lazy-load mechanism. Only CLIs listed in `install_cloud_clis_components` are included.
 
 `blockinfile` runs with **`backup: true`** (timestamped `.bashrc` backup beside the file) and sets **`mode: 0644`** on `.bashrc` when the module updates the file. Add your own completions **outside** that marked region (for example in `~/.bashrc-local` or after the block) so the role does not manage them.
 

roles/install_cloud_clis/templates/bashrc_cloud_cli_completion.j2

@@ -5,58 +5,47 @@ if command -v aws &>/dev/null; then
 fi
 
 {% endif %}
-{% if 'oc' in install_cloud_clis_components %}
-if command -v oc &>/dev/null; then
-    # shellcheck source=/dev/null
-    source <(oc completion bash)
-fi
+{% set _lazy_cli_components = ['oc', 'ocm', 'rosa', 'tekton', 'kube_linter', 'kustomize', 'stern', 'helm'] %}
+{% if _lazy_cli_components | intersect(install_cloud_clis_components) | length > 0 %}
+_lazy_completion() {
+    local cmd=$1; shift
+    local gen_args=("$@")
+    local cache="${XDG_CACHE_HOME:-$HOME/.cache}/bash_completions/${cmd}.bash"
+    eval "_complete_lazy_${cmd}() {
+        unset -f _complete_lazy_${cmd}
+        complete -r ${cmd} 2>/dev/null
+        if [[ ! -f '${cache}' || \$(command -v ${cmd}) -nt '${cache}' ]]; then
+            mkdir -p '${XDG_CACHE_HOME:-$HOME/.cache}/bash_completions'
+            \"\${gen_args[@]}\" > '${cache}'
+        fi
+        source '${cache}'
+        return 124
+    }"
+    complete -F "_complete_lazy_${cmd}" "$cmd"
+}
 
+{% if 'oc' in install_cloud_clis_components %}
+command -v oc &>/dev/null && _lazy_completion oc oc completion bash
 {% endif %}
 {% if 'ocm' in install_cloud_clis_components %}
-if command -v ocm &>/dev/null; then
-    # shellcheck source=/dev/null
-    source <(ocm completion bash)
-fi
-
+command -v ocm &>/dev/null && _lazy_completion ocm ocm completion bash
 {% endif %}
 {% if 'rosa' in install_cloud_clis_components %}
-if command -v rosa &>/dev/null; then
-    # shellcheck source=/dev/null
-    source <(rosa completion bash)
-fi
-
+command -v rosa &>/dev/null && _lazy_completion rosa rosa completion bash
 {% endif %}
 {% if 'tekton' in install_cloud_clis_components %}
-if command -v tkn &>/dev/null; then
-    # shellcheck source=/dev/null
-    source <(tkn completion bash)
-fi
-
+command -v tkn &>/dev/null && _lazy_completion tkn tkn completion bash
 {% endif %}
 {% if 'kube_linter' in install_cloud_clis_components %}
-if command -v kube-linter &>/dev/null; then
-    # shellcheck source=/dev/null
-    source <(kube-linter completion bash)
-fi
-
+command -v kube-linter &>/dev/null && _lazy_completion kube-linter kube-linter completion bash
 {% endif %}
 {% if 'kustomize' in install_cloud_clis_components %}
-if command -v kustomize &>/dev/null; then
-    # shellcheck source=/dev/null
-    source <(kustomize completion bash)
-fi
-
+command -v kustomize &>/dev/null && _lazy_completion kustomize kustomize completion bash
 {% endif %}
 {% if 'stern' in install_cloud_clis_components %}
-if command -v stern &>/dev/null; then
-    # shellcheck source=/dev/null
-    source <(stern --completion=bash)
-fi
-
+command -v stern &>/dev/null && _lazy_completion stern stern --completion=bash
 {% endif %}
 {% if 'helm' in install_cloud_clis_components %}
-if command -v helm &>/dev/null; then
-    # shellcheck source=/dev/null
-    source <(helm completion bash)
-fi
+command -v helm &>/dev/null && _lazy_completion helm helm completion bash
+{% endif %}
 {% endif %}