feature: allow downloading of package by remote host

[travisdowns]

Currently node_exporter install always downloads the package on the localhost and unpacks it there then uploads it to the remote host.

In the case the ansible controller is at the other end of a thin network pipe, or if it may not even have access to the package URL, it may be desirable to download and unpack it on the remote host instead.

This change adds that ability as an optional behavior to _common/install and wires it up for use by node_exporter, using the node_exporter_localhost_download variable. The default for node exporter and any other binaries remains the same as before: delegate to localhost.

Fixes #389.

[github-actions]

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The docs for this PR have been published here:
https://prometheus-community.github.io/ansible/pr/499

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https://prometheus-community.github.io/ansible/branch/main

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File changes:

• M node_exporter_role.html

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diff --git a/home/runner/work/ansible/ansible/docsbuild/base/node_exporter_role.html b/home/runner/work/ansible/ansible/docsbuild/head/node_exporter_role.html
index 11c04c2..dd9dbd1 100644
--- a/home/runner/work/ansible/ansible/docsbuild/base/node_exporter_role.html
+++ b/home/runner/work/ansible/ansible/docsbuild/head/node_exporter_role.html
@@ -249,6 +249,14 @@ To check whether it is installed, run <code class="code docutils literal notrans
 </div></td>
 </tr>
 <tr class="row-odd"><td><div class="ansible-option-cell">
+<div class="ansibleOptionAnchor" id="parameter-main--node_exporter_remote_download"></div><p class="ansible-option-title" id="ansible-collections-prometheus-prometheus-node-exporter-role-parameter-main-node-exporter-remote-download"><strong>node_exporter_remote_download</strong></p>
+<a class="ansibleOptionLink" href="#parameter-main--node_exporter_remote_download" title="Permalink to this option"></a><p class="ansible-option-type-line"><span class="ansible-option-type">string</span></p>
+</div></td>
+<td><div class="ansible-option-cell"><p>Determines if the node exporter package archive is downloaded and extracted on local (false) or remote host (true)</p>
+<p class="ansible-option-line"><strong class="ansible-option-default-bold">Default:</strong> <code class="ansible-option-default docutils literal notranslate"><span class="pre">true</span></code></p>
+</div></td>
+</tr>
+<tr class="row-even"><td><div class="ansible-option-cell">
 <div class="ansibleOptionAnchor" id="parameter-main--node_exporter_system_group"></div><p class="ansible-option-title" id="ansible-collections-prometheus-prometheus-node-exporter-role-parameter-main-node-exporter-system-group"><strong>node_exporter_system_group</strong></p>
 <a class="ansibleOptionLink" href="#parameter-main--node_exporter_system_group" title="Permalink to this option"></a><p class="ansible-option-type-line"><span class="ansible-option-type">string</span></p>
 </div></td>
@@ -257,7 +265,7 @@ To check whether it is installed, run <code class="code docutils literal notrans
 <p class="ansible-option-line"><strong class="ansible-option-default-bold">Default:</strong> <code class="ansible-option-default docutils literal notranslate"><span class="pre">&quot;node-exp&quot;</span></code></p>
 </div></td>
 </tr>
-<tr class="row-even"><td><div class="ansible-option-cell">
+<tr class="row-odd"><td><div class="ansible-option-cell">
 <div class="ansibleOptionAnchor" id="parameter-main--node_exporter_system_user"></div><p class="ansible-option-title" id="ansible-collections-prometheus-prometheus-node-exporter-role-parameter-main-node-exporter-system-user"><strong>node_exporter_system_user</strong></p>
 <a class="ansibleOptionLink" href="#parameter-main--node_exporter_system_user" title="Permalink to this option"></a><p class="ansible-option-type-line"><span class="ansible-option-type">string</span></p>
 </div></td>
@@ -266,7 +274,7 @@ To check whether it is installed, run <code class="code docutils literal notrans
 <p class="ansible-option-line"><strong class="ansible-option-default-bold">Default:</strong> <code class="ansible-option-default docutils literal notranslate"><span class="pre">&quot;node-exp&quot;</span></code></p>
 </div></td>
 </tr>
-<tr class="row-odd"><td><div class="ansible-option-cell">
+<tr class="row-even"><td><div class="ansible-option-cell">
 <div class="ansibleOptionAnchor" id="parameter-main--node_exporter_textfile_dir"></div><p class="ansible-option-title" id="ansible-collections-prometheus-prometheus-node-exporter-role-parameter-main-node-exporter-textfile-dir"><strong>node_exporter_textfile_dir</strong></p>
 <a class="ansibleOptionLink" href="#parameter-main--node_exporter_textfile_dir" title="Permalink to this option"></a><p class="ansible-option-type-line"><span class="ansible-option-type">string</span></p>
 </div></td>
@@ -276,7 +284,7 @@ To check whether it is installed, run <code class="code docutils literal notrans
 <p class="ansible-option-line"><strong class="ansible-option-default-bold">Default:</strong> <code class="ansible-option-default docutils literal notranslate"><span class="pre">&quot;/var/lib/node_exporter&quot;</span></code></p>
 </div></td>
 </tr>
-<tr class="row-even"><td><div class="ansible-option-cell">
+<tr class="row-odd"><td><div class="ansible-option-cell">
 <div class="ansibleOptionAnchor" id="parameter-main--node_exporter_tls_server_config"></div><p class="ansible-option-title" id="ansible-collections-prometheus-prometheus-node-exporter-role-parameter-main-node-exporter-tls-server-config"><strong>node_exporter_tls_server_config</strong></p>
 <a class="ansibleOptionLink" href="#parameter-main--node_exporter_tls_server_config" title="Permalink to this option"></a><p class="ansible-option-type-line"><span class="ansible-option-type">dictionary</span></p>
 </div></td>
@@ -284,7 +292,7 @@ To check whether it is installed, run <code class="code docutils literal notrans
 <p>Keys and values are the same as in <a class="reference external" href="https://prometheus.io/docs/prometheus/latest/configuration/https/">node_exporter docs</a>.</p>
 </div></td>
 </tr>
-<tr class="row-odd"><td><div class="ansible-option-cell">
+<tr class="row-even"><td><div class="ansible-option-cell">
 <div class="ansibleOptionAnchor" id="parameter-main--node_exporter_version"></div><p class="ansible-option-title" id="ansible-collections-prometheus-prometheus-node-exporter-role-parameter-main-node-exporter-version"><strong>node_exporter_version</strong></p>
 <a class="ansibleOptionLink" href="#parameter-main--node_exporter_version" title="Permalink to this option"></a><p class="ansible-option-type-line"><span class="ansible-option-type">string</span></p>
 </div></td>
@@ -292,7 +300,7 @@ To check whether it is installed, run <code class="code docutils literal notrans
 <p class="ansible-option-line"><strong class="ansible-option-default-bold">Default:</strong> <code class="ansible-option-default docutils literal notranslate"><span class="pre">&quot;1.8.2&quot;</span></code></p>
 </div></td>
 </tr>
-<tr class="row-even"><td><div class="ansible-option-cell">
+<tr class="row-odd"><td><div class="ansible-option-cell">
 <div class="ansibleOptionAnchor" id="parameter-main--node_exporter_web_disable_exporter_metrics"></div><p class="ansible-option-title" id="ansible-collections-prometheus-prometheus-node-exporter-role-parameter-main-node-exporter-web-disable-exporter-metrics"><strong>node_exporter_web_disable_exporter_metrics</strong></p>
 <a class="ansibleOptionLink" href="#parameter-main--node_exporter_web_disable_exporter_metrics" title="Permalink to this option"></a><p class="ansible-option-type-line"><span class="ansible-option-type">boolean</span></p>
 </div></td>
@@ -304,7 +312,7 @@ To check whether it is installed, run <code class="code docutils literal notrans
 </ul>
 </div></td>
 </tr>
-<tr class="row-odd"><td><div class="ansible-option-cell">
+<tr class="row-even"><td><div class="ansible-option-cell">
 <div class="ansibleOptionAnchor" id="parameter-main--node_exporter_web_listen_address"></div><p class="ansible-option-title" id="ansible-collections-prometheus-prometheus-node-exporter-role-parameter-main-node-exporter-web-listen-address"><strong>node_exporter_web_listen_address</strong></p>
 <a class="ansibleOptionLink" href="#parameter-main--node_exporter_web_listen_address" title="Permalink to this option"></a><p class="ansible-option-type-line"><span class="ansible-option-type">string</span></p>
 </div></td>
@@ -312,7 +320,7 @@ To check whether it is installed, run <code class="code docutils literal notrans
 <p class="ansible-option-line"><strong class="ansible-option-default-bold">Default:</strong> <code class="ansible-option-default docutils literal notranslate"><span class="pre">&quot;0.0.0.0:9100&quot;</span></code></p>
 </div></td>
 </tr>
-<tr class="row-even"><td><div class="ansible-option-cell">
+<tr class="row-odd"><td><div class="ansible-option-cell">
 <div class="ansibleOptionAnchor" id="parameter-main--node_exporter_web_telemetry_path"></div><p class="ansible-option-title" id="ansible-collections-prometheus-prometheus-node-exporter-role-parameter-main-node-exporter-web-telemetry-path"><strong>node_exporter_web_telemetry_path</strong></p>
 <a class="ansibleOptionLink" href="#parameter-main--node_exporter_web_telemetry_path" title="Permalink to this option"></a><p class="ansible-option-type-line"><span class="ansible-option-type">string</span></p>
 </div></td>

[gardar]

Thanks!
I think the _common_delegate_to_localhost variable name is a bit too generic, how about _common_remote_download and node_exporter_remote_download etc. instead?
Also I think we should implement this in all the roles at once rather than just for the node_exporter.

[travisdowns]

Also I think we should implement this in all the roles at once rather than just for the node_exporter.

Is there some efficient way to test this? I tested node_exporter (by hand, locally) but I don't think I'll be able to test all 20+ roles which rely on _common.

[travisdowns]

I think the _common_delegate_to_localhost variable name is a bit too generic, how about _common_remote_download and node_exporter_remote_download etc. instead?

Good call, I've applied your suggestion in push 19cb70e.

Subsequent pushes b793b2b and 5acb13c and f686f1b are only lint fixes (lol).

[zhan9san]

@travisdowns

Awesome. LGTM