* Support Multi-stage install with Add-Ons
* add upgrade tests for add-ons
* add multi stage upgrade unit tests
Signed-off-by: Tarun Pothulapati <tarunpothulapati@outlook.com>
* use downward API to mount labels to the proxy container as a volume
* add namespace as a label to the pod
* add a trace inject test
* add downwardAPi for controlplaneTracing
* add controlPlaneTracing condition to volumeMounts
* update add-ons to have workload-ns
* add workload-ns label to control-plane components
Signed-off-by: Tarun Pothulapati <tarunpothulapati@outlook.com>
Adds the SMI metrics API to the Linkerd install flow. This installs the SMI metrics controller deployment, the SMI metrics ApiService object, and supporting RBAC, and config resources.
This is the first step toward having Linkerd consume the SMI metrics API in the CLI and web dashboard.
Signed-off-by: Alex Leong <alex@buoyant.io>
* Moves Common templates needed to partials
As add-ons re-use the partials helm chart, all the templates needed by multiple charts should be present in partials
This commit also updates the helm tests
Signed-off-by: Tarun Pothulapati <tarunpothulapati@outlook.com>
* add tracing add-on helm chart
Tracing sub-chart includes open-census and jaeger components as a sub-chart which can be enabled as needed
* Updated Install path to also install add-ons
This includes new interface for add-ons to implement, with example tracing implementation
* Updates Linkerd install path to also install add-ons
Changes include:
- Adds an optional Linkerd Values configmap which stores add-on configuration when add-ons are present.
- Updates Linkerd install path to check for add-ons and render their sub-charts.
- Adds a install Option called config, which is used to pass confiugration for add-ons.
- Uses a fork of mergo, to over-write default Values with the Values struct generated from config.
* Updates the upgrade path about add-ons.
Upgrade path now checks for the linkerd-values cm, and overwrites the default values with it, if present.
It then checks the config option, for any further overwrites
* Refactor linkerd-values and re-update tests
also adds relevant nil checks
* Refactor code to fix linting issues
* Fixes an error with linkerd-config global values
Also refactors the linkerd-values cm to work the same with helm
* Fix a nil pointer issue for tests
* Updated Tracing add-on chart meta-data
Also introduced a defaultGetFiles method for add-ons
* Add add-on/charts to gitignore
* refactor gitignore for chart deps
* Moves sub-charts to /charts directly
* Refactor linkerd values cm
* Add comment in linkerd-values
* remove extra controlplanetracing flag
* Support Stages deployment for add-ons along with tests
* linting fix
* update tracing rbac
* Removes the need for add-on Interface
- Uses helm loading capabiltiies to get info about add-ons
- Uses reflection to not have to unnecessarily add checks for each add-on type
* disable tracing flag
* Remove dep on forked mergo
- Re-use merge from helm
* Re-use helm's merge
* Override the chartDir path during tests
* add error check
* Updated the dependency iteration code
Currently, the charts directory, will not have the deps in the repo. So, Code is updated to read the dependencies from requirements.yaml
and use that info to read templates from the relevant add-ons directory.
* Hard Code add-ons name
* Remove struct details for add-ons
- As we don't use fields of a add-on struct, we don't have them to be typed. Instead we can just use the `enabled` flag using reflection
- Users can just use map[string]interface{} as the add-on type.
* update unit tests
* linting fix
* Rename flag to addon-config
* Use Chart loading logic
- This code uses chart loading to read the files and keep in a vfs.
- Once we have those files read we will then use them for generation of sub-charts.
* Go fmt fix
* Update the linkerd-values cm to use second level field
* Add relevant unit tests for mergeRaw
* linting fix
* Move addon tests to a new file
* Fix golden files
* remove addon install unit test
* Refactor sub-chart load logic
* Add install tracing unit test
* golden file update for tracing install
* Update golden files to reflect another pr changes
* Move addon-config flag to recordFlagSet
* add relevant tracing enabled checks
* linting fix
Signed-off-by: Tarun Pothulapati <tarunpothulapati@outlook.com>
**Subject**
Fixes bug where override of Docker registry was not being applied to debug containers (#3851)
**Problem**
Overrides for Docker registry are not being applied to debug containers and provide no means to correct the image.
**Solution**
This update expands the `data.proxy` configuration section within the Linkerd `ConfigMap` to maintain the overridden image name for debug containers at _install_-time similar to handling of the `proxy` and `proxyInit` images.
This change also enables the further override option of the registry for debug containers at _inject_-time given utilization of the `--registry` CLI option.
**Validation**
Several new unit tests have been created to confirm functionality. In addition, the following workflows were run through:
### Standard Workflow with Custom Registry
This workflow installs Linkerd control plane based upon a custom registry, then injecting the debug sidecar into a service.
* Start with a k8s instance having no Linkerd installation
* Build all images locally using `bin/docker-build`
* Create custom tags (using same version) for generated images, e.g. `docker tag gcr.io/linkerd-io/debug:git-a4ebecb6 javaducky.com/linkerd-io/debug:git-a4ebecb6`
* Install Linkerd with registry override `bin/linkerd install --registry=javaducky.com/linkerd-io | kubectl apply -f -`
* Once Linkerd has been fully initialized, you should be able to confirm that the `linkerd-config` ConfigMap now contains the debug image name, pull policy, and version within the `data.proxy` section
* Request injection of the debug image into an available container. I used the Emojivoto voting service as described in https://linkerd.io/2/tasks/using-the-debug-container/ as `kubectl -n emojivoto get deploy/voting -o yaml | bin/linkerd inject --enable-debug-sidecar - | kubectl apply -f -`
* Once the deployment creates a new pod for the service, inspection should show that the container now includes the "linkerd-debug" container name based on the applicable override image seen previously within the ConfigMap
* Debugging can also be verified by viewing debug container logs as `kubectl -n emojivoto logs deploy/voting linkerd-debug -f`
* Modifying the `config.linkerd.io/enable-debug-sidecar` annotation, setting to “false”, should show that the pod will be recreated no longer running the debug container.
### Overriding the Custom Registry Override at Injection
This builds upon the “Standard Workflow with Custom Registry” by overriding the Docker registry utilized for the debug container at the time of injection.
* “Clean” the Emojivoto voting service by removing any Linkerd annotations from the deployment
* Request injection similar to before, except provide the `--registry` option as in `kubectl -n emojivoto get deploy/voting -o yaml | bin/linkerd inject --enable-debug-sidecar --registry=gcr.io/linkerd-io - | kubectl apply -f -`
* Inspection of the deployment config should now show the override annotation for `config.linkerd.io/debug-image` having the debug container from the new registry. Viewing the running pod should show that the `linkerd-debug` container was injected and running the correct image. Of note, the proxy and proxy-init images are still running the “original” override images.
* As before, modifying the `config.linkerd.io/enable-debug-sidecar` annotation setting to “false”, should show that the pod will be recreated no longer running the debug container.
### Standard Workflow with Default Registry
This workflow is the typical workflow which utilizes the standard Linkerd image registry.
* Uninstall the Linkerd control plane using `bin/linkerd install --ignore-cluster | kubectl delete -f -` as described at https://linkerd.io/2/tasks/uninstall/
* Clean the Emojivoto environment using `curl -sL https://run.linkerd.io/emojivoto.yml | kubectl delete -f -` then reinstall using `curl -sL https://run.linkerd.io/emojivoto.yml | kubectl apply -f -`
* Perform standard Linkerd installation as `bin/linkerd install | kubectl apply -f -`
* Once Linkerd has been fully initialized, you should be able to confirm that the `linkerd-config` ConfigMap references the default debug image of `gcr.io/linkerd-io/debug` within the `data.proxy` section
* Request injection of the debug image into an available container as `kubectl -n emojivoto get deploy/voting -o yaml | bin/linkerd inject --enable-debug-sidecar - | kubectl apply -f -`
* Debugging can also be verified by viewing debug container logs as `kubectl -n emojivoto logs deploy/voting linkerd-debug -f`
* Modifying the `config.linkerd.io/enable-debug-sidecar` annotation, setting to “false”, should show that the pod will be recreated no longer running the debug container.
### Overriding the Default Registry at Injection
This workflow builds upon the “Standard Workflow with Default Registry” by overriding the Docker registry utilized for the debug container at the time of injection.
* “Clean” the Emojivoto voting service by removing any Linkerd annotations from the deployment
* Request injection similar to before, except provide the `--registry` option as in `kubectl -n emojivoto get deploy/voting -o yaml | bin/linkerd inject --enable-debug-sidecar --registry=javaducky.com/linkerd-io - | kubectl apply -f -`
* Inspection of the deployment config should now show the override annotation for `config.linkerd.io/debug-image` having the debug container from the new registry. Viewing the running pod should show that the `linkerd-debug` container was injected and running the correct image. Of note, the proxy and proxy-init images are still running the “original” override images.
* As before, modifying the `config.linkerd.io/enable-debug-sidecar` annotation setting to “false”, should show that the pod will be recreated no longer running the debug container.
Fixes issue #3851
Signed-off-by: Paul Balogh javaducky@gmail.com
* update flags to smaller
* add tests for the same
* fix control plane trace flag
* add tests for controlplane tracing install
Signed-off-by: Tarun Pothulapati <tarunpothulapati@outlook.com>
* Enable mixed configuration of skip-[inbound|outbound]-ports using port numbers and ranges (#3752)
* included tests for generated output given proxy-ignore configuration options
* renamed "validate" method to "parseAndValidate" given mutation
* updated documentation to denote inclusiveness of ranges
* Updates for expansion of ignored inbound and outbound port ranges to be handled by the proxy-init rather than CLI (#3766)
This change maintains the configured ports and ranges as strings rather than unsigned integers, while still providing validation at the command layer.
* Bump versions for proxy-init to v1.3.0
Signed-off-by: Paul Balogh <javaducky@gmail.com>
This PR adds support for CronJobs and ReplicaSets to `linkerd inject`, the web
dashboard and CLI. It adds a new Grafana dashboard for each kind of resource.
Closes#3614Closes#3630Closes#3584Closes#3585
Signed-off-by: Sergio Castaño Arteaga tegioz@icloud.com
Signed-off-by: Cintia Sanchez Garcia cynthiasg@icloud.com
* No need for `processYAML()` in `install`
Since `install` uses helm to do its proxy injection, there's no need to
call `processYAML`. This also fixes an issue discovered in #3687 where
we started supporting injection of cronjobs, and even though `linkerd`'s
namespace is flagged to skip automatic injection it was being injected.
This replaces #3773 as it's a much more simpler approach.
* Replaced `uuid` with `uid` from linkerd-config resource
Fixes#3621
Removed the old `uuid` for identifying linkerd installations, and
replaced it with the `uid` property from the `linkerd-config` ConfigMap.
I tested that this `uid` remains the same by updating the config and
also upgrading linkerd, using both the CLI and Helm.
Note that this required granting `linkerd-web` RBAC access to the
`linkerd-config` Config.
I also added an integration test to verify the stability of the uid.
* Add support for --identity-issuer-mode flag to install cmd
* Change flag to be a bool
* Read correct data form identity when external issuer is used
* Add ability for identity service to dynamically reload certs
* Fix failing tests
* Minor refactor
* Load trust anchors from identity issuer secret
* Make identity service actually watch for issuer certs updates
* Add some testing around cmd line identity options validation
* Add tests ensuring that identity service loads issuer
* Take into account external-issuer flag during upgrade + tests
* Fix failing upgrade test
* Address initial review feedback
* Address further review feedback on cli and helm
* Do not persist --identity-external-issuer
* Some improvements to identitiy service
* Bring back persistane of external issuer flag
* Address more feedback
* Update dockerfiles shas
* Publishing k8s events on issuer certs rotation
* Ensure --ignore-cluster+external issuer is not supported
* Update go-deps shas
* Transition to identity issuer scheme based configuration
* Use k8s consts for secret file names
Signed-off-by: zaharidichev <zaharidichev@gmail.com>
This reverts commit edd3b1f6d4.
This is a temporary revert of #3461 while we sort out some details of how this should configured and how it should interact with configuring a trace collector on the Linkerd proxy. We will reintroduce this change once the config plan is straightened out.
Signed-off-by: Alex Leong <alex@buoyant.io>
If the namespace is controlled by an external tool or can't be installed
with Helm, disable its installation
Fixes#3412
Signed-off-by: Eugene Glotov <kivagant@gmail.com>
* Rename template-values.go
* Define new constructor of charts.Values type
* Move all Helm values related code to the pkg/charts package
* Bump dependency
* Use '/' in filepath to remain compatible with VFS requirement
* Add unit test to verify Helm YAML output
* Alejandro's feedback
* Add unit test for Helm YAML validation (HA)
Signed-off-by: Ivan Sim <ivan@buoyant.io>
* Delete symlink to old Helm chart
* Update 'install' code to use common Helm template structs
* Remove obsolete TLS assets functions.
These are now handle by Helm functions inside the templates
* Read defaults from values.yaml and values-ha.yaml
* Ensure that webhooks TLS assets are retained during upgrade
* Fix a few bugs in the Helm templates (see bullet points):
* Merge the way the 'install' ha and non-ha options are handled into one function
* Honor the 'NoInitContainer' option in the components templates
* Control plane mTLS will not be disabled if identity context in the
config map is empty. The data plane mTLS will still be automatically disabled
if the context is nil.
* Resolve test failures from rebase with master
* Fix linter issues
* Set service account mount path read-only field
* Add TLS variables of the webhooks and tap to values.yaml
During upgrade, these secrets are preserved to ensure they remain synced
wih the CA bundle in the webhook configurations. These Helm variables are used
to override the defaults in the templates.
* Remove obsolete 'chart' folder
* Fix bugs in templates
* Handle missing webhooks and tap TLS assets during upgrade
When upgrading from an older version that don't have these secrets, fallback to let Helm
create them by creating an empty charts.TLS struct.
* Revert the selector labels of webhooks to be compatible with that in 2.4
In 2.4, the proxy injector and profile validator webhooks already have their selector labels defined.
Since these attributes are immutable, the recent change to these selectors introduced by the Helm chart work will cause upgrade to fail.
* Alejandro's feedback
* Siggy's feedback
* Removed redundant unexported custom types
Signed-off-by: Ivan Sim <ivan@buoyant.io>
The web dashboard will be migrating to the new Tap APIService, which
requires RBAC privileges to access.
Introduce a new ClusterRole, `linkerd-linkerd-tap-admin`, which gives
cluster-wide tap privileges. Also introduce a new ClusterRoleBinding,
`linkerd-linkerd-web-admin` which binds the `linkerd-web` service
account to the new tap ClusterRole. This ClusterRoleBinding is enabled
by default, but may be disabled via a new `linkerd install` flag
`--restrict-dashboard-privileges`.
Fixes#3177
Signed-off-by: Andrew Seigner <siggy@buoyant.io>
The Tap Service enabled tapping of any meshed pod, regardless of user
privilege.
This change introduces a new Tap APIService. Kubernetes provides
authentication and authorization of Tap requests, and then forwards
requests to a new Tap APIServer, which implements a Kubernetes
aggregated APIServer. The Tap APIServer authenticates the client TLS
from Kubernetes, and authorizes the user via a SubjectAccessReview.
This change also modifies the `linkerd tap` command to make requests
against the new APIService.
The Tap APIService implements these Kubernetes-style endpoints:
POST /apis/tap.linkerd.io/v1alpha1/watch/namespaces/:ns/tap
POST /apis/tap.linkerd.io/v1alpha1/watch/namespaces/:ns/:res/:name/tap
GET /apis
GET /apis/tap.linkerd.io
GET /apis/tap.linkerd.io/v1alpha1
GET /healthz
GET /healthz/log
GET /healthz/ping
GET /metrics
GET /openapi/v2
GET /version
Users authorize to the new `tap.linkerd.io/v1alpha1` via RBAC. Only the
`watch` verb is supported. Access is also available via subresources
such as `deployments/tap` and `pods/tap`.
This change introduces the following resources into the default Linkerd
install:
- Global
- APIService/v1alpha1.tap.linkerd.io
- ClusterRoleBinding/linkerd-linkerd-tap-auth-delegator
- `linkerd` namespace:
- Secret/linkerd-tap-tls
- `kube-system` namespace:
- RoleBinding/linkerd-linkerd-tap-auth-reader
Tasks not covered by this PR:
- `linkerd top`
- `linkerd dashboard`
- `linkerd profile --tap`
- removal of the unauthenticated tap controller
Fixes#2725, #3162, #3172
Signed-off-by: Andrew Seigner <siggy@buoyant.io>
`linkerd check`, the web dashboard, and Grafana all perform version
checks to validate Linkerd is up to date. It's common for users to
seldom execute these codepaths. This makes it difficult to identify what
versions of Linkerd are currently in use and what environments it is
being run in, which helps prioritize testing and backports.
Introduce a `heartbeat` CronJob to the default Linkerd install. The
cronjob executes every 24 hours, starting from 5 minutes after
`linkerd install` is run.
Example check URL:
https://versioncheck.linkerd.io/version.json?
install-time=1562761177&
k8s-version=v1.15.0&
meshed-pods=8&
rps=3&
source=heartbeat&
uuid=cc4bb700-3314-426a-9f0f-ec588b9df020&
version=git-b97ee9f7
Fixes#2961
Signed-off-by: Andrew Seigner <siggy@buoyant.io>
* Allow custom cluster domain in destination watcher
The change relaxes the constrains of an authority requiring a
`svc.cluster.local` suffix to only require `svc` as third part.
A unit test could be added though the destination/server and endpoint
watcher already test this behaviour.
* Update proto to allow setting custom cluster domain
Update golden templates
* Allow setting custom domain in grpc, web server
* Remove cluster domain flags from web srv and public api
* Set defaultClusterDomain in validateAndBuild if none is set
Signed-off-by: Armin Buerkle <armin.buerkle@alfatraining.de>
Fixes#2927
Also moved `TestInstallSP` after `TestCheckPostInstall` so we're sure
the validating webhook is ready before installing a service profile.
Signed-off-by: Alejandro Pedraza Borrero <alejandro@buoyant.io>
* If HA, set the webhooks failure policy to 'Fail'
I'm adding to the linkerd namespace a new label
`linkerd.io/is-control-plane: true` that is used in the webhook configs'
selector to skip the proxy injector for this namespace. This avoids
running into the timing issues described in #2852.
Fixes#2852
Signed-off-by: Alejandro Pedraza <alejandro@buoyant.io>
* Update helm charts to include webhooks config and TLS secret
* Update the webhooks to read the secret cert and key
* Update webhooks to not recreate config on restart
* Ensure upgrade preserve existing secrets
* Revert the change to rename the webhook configs
The renaming change breaks upgrade, where the new webhook configs conflict with
the existing ones. The older resources aren't deleted during upgrade because
they are dynamically created.
* Make the secret volume read-only
* Remove unnecessary exported getter functions
* Remove obsolete mwc and vwc templates
Signed-off-by: Ivan Sim <ivan@buoyant.io>
* The 'linkerd-version' CLI flag is renamed to 'control-plane-version'
* Add version field to proxy config
* Add the control plane version to the global config
* Unit test for init image version
* Use more specific control plane and proxy versions in unit tests
Signed-off-by: Ivan Sim <ivan@buoyant.io>
The `install` command errors when the deploy target contains an existing
Linkerd deployment. The `upgrade` command is introduced to reinstall or
reconfigure the Linkerd control plane.
Upgrade works as follows:
1. The controller config is fetched from the Kubernetes API. The Public
API is not used, because we need to be able to reinstall the control
plane when the Public API is not available; and we are not concerned
about RBAC restrictions preventing the installer from reading the
config (as we are for inject).
2. The install configuration is read, particularly the flags used during
the last install/upgrade. If these flags were not set again during the
upgrade, the previous values are used as if they were passed this time.
The configuration is updated from the combination of these values,
including the install configuration itself.
Note that some flags, including the linkerd-version, are omitted
since they are stored elsewhere in the configurations and don't make
sense to track as overrides..
3. The issuer secrets are read from the Kubernetes API so that they can
be re-used. There is currently no way to reconfigure issuer
certificates. We will need to create _another_ workflow for
updating these credentials.
4. The install rendering is invoked with values and config fetched from
the cluster, synthesized with the new configuration.
When installing Linkerd, a user may override default settings, or may
explicitly configure defaults. Consider install options like `--ha
--controller-replicas=4` -- the `--ha` flag sets a new default value for
the controller-replicas, and then we override it.
When we later upgrade this cluster, how can we know how to configure the
cluster?
We could store EnableHA and ControllerReplicas configurations in the
config, but what if, in a later upgrade, the default value changes? How
can we know whether the user specified an override or just used the
default?
To solve this, we add an `Install` message into a new config.
This message includes (at least) the CLI flags used to invoke
install.
upgrade does not specify defaults for install/proxy-options fields and,
instead, uses the persisted install flags to populate default values,
before applying overrides from the upgrade invocation.
This change breaks the protobuf compatibility by altering the
`installation_uuid` field introduced in 9c442f6885.
Because this change was not yet released (even in an edge release), we
feel that it is safe to break.
Fixes https://github.com/linkerd/linkerd2/issues/2574
This change moves resource-templating logic into a dedicated template,
creates new values types to model kubernetes resource constraints, and
changes the `--ha` flag's behavior to create these resource templates
instead of hardcoding the resource constraints in the various templates.
Currently, the install UUID is regenerated each time `install` is run.
When implementing cluster upgrades, it seems most appropriate to reuse
the prior UUID, rather than generate a new one.
To this end, this change stores an "Installation UUID" in the global
linkerd config.
Because the linkerd-config resource is created after pods that require
it, they can be started before the files are mounted, causing the pods
to restart integration tests to fail.
If we extract the config into its own template file, it can be inserted
before pods are created.
The introduction of identity in 0626fa37 created new state in the
control plane's configuration that must be considered when re-installing
the control plane or when injecting pods.
This change alters `install` to fail if it would seem to conflict with
an existing installation. This behavior may be disabled with the
`--ignore-cluster` flag.
Furthermore, `inject` now _requires_ that it can fetch a configuration
from the control plane in order to operate. Otherwise the
`--ignore-cluster` and `--disable-identity` flags must be specified.
This change does not actually instrument pods to use identity yet---it
lays the framework for proxy identity without changing the test fixture
output (besides a change to how identity HA is configured).
Fixes#2531
https://github.com/linkerd/linkerd2/pull/2521 introduces an "Identity"
controller, but there is no way to include it in linkerd installation.
This change alters the `install` flow as follows:
- An Identity service is _always_ installed;
- Issuer credentials may be specified via the CLI;
- If no Issuer credentials are provided, they are generated each time `install` is called.
- Proxies are NOT configured to use the identity service.
- It's possible to override the credential generation logic---especially
for tests---via install options that can be configured via the CLI.
The proxy's TLS implementation has changed to use a new _Identity_ controller.
In preparation for this, the `--tls=optional` CLI flag has been removed
from install and inject; and the `ca` controller has been deleted. Metrics
and UI treatments for TLS have **not** been removed, as they will continue to
be valuable for the new Identity system.
With the removal of the old identity scheme, the Destination service's proxy
ID field is now set with an opaque string (e.g. `ns:emojivoto`) to enable
locality awareness.
linkerd/linkerd2#1721 introduced a `--single-namespace` install flag,
enabling the control-plane to function within a single namespace. With
the introduction of ServiceProfiles, and upcoming identity changes, this
single namespace mode of operation is becoming less viable.
This change removes the `--single-namespace` install flag, and all
underlying support. The control-plane must have cluster-wide access to
operate.
A few related changes:
- Remove `--single-namespace` from `linkerd check`, this motivates
combining some check categories, as we can always assume cluster-wide
requirements.
- Simplify the `k8s.ResourceAuthz` API, as callers no longer need to
make a decision based on cluster-wide vs. namespace-wide access.
Components either have access, or they error out.
- Modify the web dashboard to always assume ServiceProfiles are enabled.
Reverts #1721
Part of #2337
Signed-off-by: Andrew Seigner <siggy@buoyant.io>
* Changed the protobuf definition to take out destinationApiPort entirely
* Store destinationAPIPort as a constant in pkg/inject.go
Fixes#2351
Signed-off-by: Aditya Sharma <hello@adi.run>
- Created the pkg/inject package to hold the new injection shared lib.
- Extracted from `/cli/cmd/inject.go` and `/cli/cmd/inject_util.go`
the core methods doing the workload parsing and injection, and moved them into
`/pkg/inject/inject.go`. The CLI files should now deal only with
strictly CLI concerns, and applying the json patch returned by the new
lib.
- Proceeded analogously with `/cli/cmd/uninject.go` and
`/pkg/inject/uninject.go`.
- The `InjectReport` struct and helping methods were moved into
`/pkg/inject/report.go`
- Refactored webhook to use the new injection lib
- Removed linkerd-proxy-injector-sidecar-config ConfigMap
- Added the ability to add pod labels and annotations without having to
specify the already existing ones
Fixes#1748, #2289
Signed-off-by: Alejandro Pedraza <alejandro.pedraza@gmail.com>
goconst finds repeated strings that could be replaced by a constant:
https://github.com/jgautheron/goconst
Part of #217
Signed-off-by: Andrew Seigner <siggy@buoyant.io>