[feat] hot load secret

[tchinmai7]

Today, the linode-api-token is injected into the environment by kubernetes when the CCM is installed via helm. This PR changes it to a mounted file, which allows for the secret to be updated without requiring a restart of the ccm pods. Also adds a 1 min cache, so we don't read the file on every request

General:

• Have you removed all sensitive information, including but not limited to access keys and passwords?
• Have you checked to ensure there aren't other open or closed Pull Requests for the same bug/feature/question?

Pull Request Guidelines:

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2. Have you added tests?
3. Are you addressing a single feature in this PR?
4. Are your commits atomic, addressing one change per commit?
5. Are you following the conventions of the language?
6. Have you saved your large formatting changes for a different PR, so we can focus on your work?
7. Have you explained your rationale for why this feature is needed?
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[codecov]

Codecov Report

❌ Patch coverage is 75.00000% with 20 lines in your changes missing coverage. Please review.
✅ Project coverage is 73.60%. Comparing base (67d4687) to head (19c469e).

Files with missing lines	Patch %	Lines
cloud/linode/client/client.go	37.50%	9 Missing and 1 partial ⚠️
cloud/linode/cloud.go	88.52%	4 Missing and 3 partials ⚠️
cloud/linode/route_controller.go	0.00%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #576      +/-   ##
==========================================
- Coverage   73.63%   73.60%   -0.03%     
==========================================
  Files          19       19              
  Lines        2958     3027      +69     
==========================================
+ Hits         2178     2228      +50     
- Misses        525      539      +14     
- Partials      255      260       +5     

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[Copilot]

Pull request overview

This PR updates the Linode Cloud Controller Manager to source the Linode API token from a Kubernetes Secret at runtime (with caching), enabling token rotation without restarting the CCM. It also updates deployment manifests/Helm chart to configure the Secret reference via new CLI flags instead of injecting LINODE_API_TOKEN as an environment variable.

Changes:

• Add CLI flags and options for token Secret name/key/namespace, and switch token loading to a Kubernetes Secret provider with caching.
• Update the Linode API client to support a dynamic token provider (per-request Authorization header).
• Update Helm chart and static manifest to pass the new flags and remove LINODE_API_TOKEN env var usage; add/adjust unit tests for the new behavior.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
main.go	Adds CLI flags for token Secret name/key/namespace configuration.
cloud/linode/options/options.go	Extends options struct with token Secret reference fields.
cloud/linode/cloud.go	Implements Secret-backed token provider with caching and wires it into Linode client creation.
cloud/linode/client/client.go	Adds a token-injecting transport and TokenProvider support to refresh tokens without restarting.
cloud/linode/cloud_test.go	Adds tests for token caching/TTL parsing and updates existing newCloud tests to use fake Secret.
deploy/chart/values.yaml	Documents optional Secret namespace in Helm values.
deploy/chart/templates/daemonset.yaml	Passes new token Secret flags and removes LINODE_API_TOKEN env var injection.
deploy/ccm-linode-template.yaml	Updates static manifest to pass new token Secret flags and removes LINODE_API_TOKEN env var injection.

[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.