pulumi/pkg/resource/plugin/provider.go
Alex Clemmer a172f1a048 Implement partial Read
Some time ago, we introduced the concept of the initialization error to
Pulumi (i.e., an error where the resource was successfully created but
failed to fully initialize). This was originally implemented in `Create`
and `Update`  methods of the resource provider interface; when we
detected an initialization failure, we'd pack the live version of the
object into the error, and return that to the engine.

Omitted from this initial implementation was a similar semantics for
`Read`. There are many implications of this, but one of them is that a
`pulumi refresh` will erase any initialization errors that had
previously been observed, even if the initialization errors still exist
in the resource.

This commit will introduce the initialization error semantics to `Read`,
fixing this issue.
2018-08-10 15:10:14 -07:00

110 lines
6 KiB
Go

// Copyright 2016-2018, Pulumi Corporation.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package plugin
import (
"io"
"github.com/pulumi/pulumi/pkg/resource"
"github.com/pulumi/pulumi/pkg/tokens"
"github.com/pulumi/pulumi/pkg/workspace"
)
// Provider presents a simple interface for orchestrating resource create, reead, update, and delete operations. Each
// provider understands how to handle all of the resource types within a single package.
//
// This interface hides some of the messiness of the underlying machinery, since providers are behind an RPC boundary.
//
// It is important to note that provider operations are not transactional. (Some providers might decide to offer
// transactional semantics, but such a provider is a rare treat.) As a result, failures in the operations below can
// range from benign to catastrophic (possibly leaving behind a corrupt resource). It is up to the provider to make a
// best effort to ensure catastrophes do not occur. The errors returned from mutating operations indicate both the
// underlying error condition in addition to a bit indicating whether the operation was successfully rolled back.
type Provider interface {
// Closer closes any underlying OS resources associated with this provider (like processes, RPC channels, etc).
io.Closer
// Pkg fetches this provider's package.
Pkg() tokens.Package
// CheckConfig validates the configuration for this resource provider.
CheckConfig(olds, news resource.PropertyMap) (resource.PropertyMap, []CheckFailure, error)
// DiffConfig checks what impacts a hypothetical change to this provider's configuration will have on the provider.
DiffConfig(olds, news resource.PropertyMap) (DiffResult, error)
// Configure configures the resource provider with "globals" that control its behavior.
Configure(inputs resource.PropertyMap) error
// Check validates that the given property bag is valid for a resource of the given type and returns the inputs
// that should be passed to successive calls to Diff, Create, or Update for this resource.
Check(urn resource.URN, olds, news resource.PropertyMap,
allowUnknowns bool) (resource.PropertyMap, []CheckFailure, error)
// Diff checks what impacts a hypothetical update will have on the resource's properties.
Diff(urn resource.URN, id resource.ID, olds resource.PropertyMap, news resource.PropertyMap,
allowUnknowns bool) (DiffResult, error)
// Create allocates a new instance of the provided resource and returns its unique resource.ID.
Create(urn resource.URN, news resource.PropertyMap) (resource.ID, resource.PropertyMap, resource.Status, error)
// Read the current live state associated with a resource. Enough state must be include in the inputs to uniquely
// identify the resource; this is typically just the resource ID, but may also include some properties. If the
// resource is missing (for instance, because it has been deleted), the resulting property map will be nil.
Read(urn resource.URN, id resource.ID,
props resource.PropertyMap) (resource.PropertyMap, resource.Status, error)
// Update updates an existing resource with new values.
Update(urn resource.URN, id resource.ID,
olds resource.PropertyMap, news resource.PropertyMap) (resource.PropertyMap, resource.Status, error)
// Delete tears down an existing resource.
Delete(urn resource.URN, id resource.ID, props resource.PropertyMap) (resource.Status, error)
// Invoke dynamically executes a built-in function in the provider.
Invoke(tok tokens.ModuleMember, args resource.PropertyMap) (resource.PropertyMap, []CheckFailure, error)
// GetPluginInfo returns this plugin's information.
GetPluginInfo() (workspace.PluginInfo, error)
// SignalCancellation asks all resource providers to gracefully shut down and abort any ongoing
// operations. Operation aborted in this way will return an error (e.g., `Update` and `Create`
// will either a creation error or an initialization error. SignalCancellation is advisory and
// non-blocking; it is up to the host to decide how long to wait after SignalCancellation is
// called before (e.g.) hard-closing any gRPC connection.
SignalCancellation() error
}
// CheckFailure indicates that a call to check failed; it contains the property and reason for the failure.
type CheckFailure struct {
Property resource.PropertyKey // the property that failed checking.
Reason string // the reason the property failed to check.
}
// DiffChanges represents the kind of changes detected by a diff operation.
type DiffChanges int
const (
// DiffUnknown indicates the provider didn't offer information about the changes (legacy behavior).
DiffUnknown DiffChanges = 0
// DiffNone indicates the provider performed a diff and concluded that no update is needed.
DiffNone DiffChanges = 1
// DiffSome indicates the provider performed a diff and concluded that an update or replacement is needed.
DiffSome DiffChanges = 2
)
// DiffResult indicates whether an operation should replace or update an existing resource.
type DiffResult struct {
Changes DiffChanges // true if this diff represents a changed resource.
ReplaceKeys []resource.PropertyKey // an optional list of replacement keys.
StableKeys []resource.PropertyKey // an optional list of property keys that are stable.
DeleteBeforeReplace bool // if true, this resource must be deleted before recreating it.
}
// Replace returns true if this diff represents a replacement.
func (r DiffResult) Replace() bool {
return len(r.ReplaceKeys) > 0
}