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| 1 | +package software.amazon.lambda.powertools.parameters; |
| 2 | + |
| 3 | +import software.amazon.awssdk.auth.credentials.EnvironmentVariableCredentialsProvider; |
| 4 | +import software.amazon.awssdk.core.SdkSystemSetting; |
| 5 | +import software.amazon.awssdk.http.urlconnection.UrlConnectionHttpClient; |
| 6 | +import software.amazon.awssdk.regions.Region; |
| 7 | +import software.amazon.awssdk.services.dynamodb.DynamoDbClient; |
| 8 | +import software.amazon.awssdk.services.dynamodb.model.*; |
| 9 | +import software.amazon.lambda.powertools.parameters.cache.CacheManager; |
| 10 | +import software.amazon.lambda.powertools.parameters.exception.DynamoDbProviderSchemaException; |
| 11 | +import software.amazon.lambda.powertools.parameters.transform.TransformationManager; |
| 12 | + |
| 13 | +import java.util.Collections; |
| 14 | +import java.util.Map; |
| 15 | +import java.util.stream.Collectors; |
| 16 | + |
| 17 | +/** |
| 18 | + * Implements a {@link ParamProvider} on top of DynamoDB. The schema of the table |
| 19 | + * is described in the Powertools documentation. |
| 20 | + * |
| 21 | + * @see <a href="https://awslabs.github.io/aws-lambda-powertools-java/utilities/parameters">Parameters provider documentation</a> |
| 22 | + * |
| 23 | + */ |
| 24 | +public class DynamoDbProvider extends BaseProvider { |
| 25 | + |
| 26 | + private final DynamoDbClient client; |
| 27 | + private final String tableName; |
| 28 | + |
| 29 | + public DynamoDbProvider(CacheManager cacheManager, String tableName) { |
| 30 | + this(cacheManager, DynamoDbClient.builder() |
| 31 | + .httpClientBuilder(UrlConnectionHttpClient.builder()) |
| 32 | + .credentialsProvider(EnvironmentVariableCredentialsProvider.create()) |
| 33 | + .region(Region.of(System.getenv(SdkSystemSetting.AWS_REGION.environmentVariable()))) |
| 34 | + .build(), |
| 35 | + tableName |
| 36 | + ); |
| 37 | + |
| 38 | + } |
| 39 | + |
| 40 | + DynamoDbProvider(CacheManager cacheManager, DynamoDbClient client, String tableName) { |
| 41 | + super(cacheManager); |
| 42 | + this.client = client; |
| 43 | + this.tableName = tableName; |
| 44 | + } |
| 45 | + |
| 46 | + /** |
| 47 | + * Return a single value from the DynamoDB parameter provider. |
| 48 | + * |
| 49 | + * @param key key of the parameter |
| 50 | + * @return The value, if it exists, null if it doesn't. Throws if the row exists but doesn't match the schema. |
| 51 | + */ |
| 52 | + @Override |
| 53 | + protected String getValue(String key) { |
| 54 | + GetItemResponse resp = client.getItem(GetItemRequest.builder() |
| 55 | + .tableName(tableName) |
| 56 | + .key(Collections.singletonMap("id", AttributeValue.fromS(key))) |
| 57 | + .attributesToGet("value") |
| 58 | + .build()); |
| 59 | + |
| 60 | + // If we have an item at the key, we should be able to get a 'val' out of it. If not it's |
| 61 | + // exceptional. |
| 62 | + // If we don't have an item at the key, we should return null. |
| 63 | + if (resp.hasItem() && !resp.item().values().isEmpty()) { |
| 64 | + if (!resp.item().containsKey("value")) { |
| 65 | + throw new DynamoDbProviderSchemaException("Missing 'value': " + resp.item().toString()); |
| 66 | + } |
| 67 | + return resp.item().get("value").s(); |
| 68 | + } |
| 69 | + |
| 70 | + return null; |
| 71 | + } |
| 72 | + |
| 73 | + /** |
| 74 | + * Returns multiple values from the DynamoDB parameter provider. |
| 75 | + * |
| 76 | + * @param path Parameter store path |
| 77 | + * @return All values matching the given path, and an empty map if none do. Throws if any records exist that don't match the schema. |
| 78 | + */ |
| 79 | + @Override |
| 80 | + protected Map<String, String> getMultipleValues(String path) { |
| 81 | + |
| 82 | + QueryResponse resp = client.query(QueryRequest.builder() |
| 83 | + .tableName(tableName) |
| 84 | + .keyConditionExpression("id = :v_id") |
| 85 | + .expressionAttributeValues(Collections.singletonMap(":v_id", AttributeValue.fromS(path))) |
| 86 | + .build()); |
| 87 | + |
| 88 | + return resp |
| 89 | + .items() |
| 90 | + .stream() |
| 91 | + .peek((i) -> { |
| 92 | + if (!i.containsKey("sk")) { |
| 93 | + throw new DynamoDbProviderSchemaException("Missing 'sk': " + i.toString()); |
| 94 | + } |
| 95 | + if (!i.containsKey("value")) { |
| 96 | + throw new DynamoDbProviderSchemaException("Missing 'value': " + i.toString()); |
| 97 | + } |
| 98 | + }) |
| 99 | + .collect( |
| 100 | + Collectors.toMap( |
| 101 | + (i) -> i.get("sk").s(), |
| 102 | + (i) -> i.get("value").s())); |
| 103 | + |
| 104 | + |
| 105 | + } |
| 106 | + |
| 107 | + /** |
| 108 | + * Create a builder that can be used to configure and create a {@link DynamoDbProvider}. |
| 109 | + * |
| 110 | + * @return a new instance of {@link DynamoDbProvider.Builder} |
| 111 | + */ |
| 112 | + public static DynamoDbProvider.Builder builder() { |
| 113 | + return new DynamoDbProvider.Builder(); |
| 114 | + } |
| 115 | + |
| 116 | + static class Builder { |
| 117 | + private DynamoDbClient client; |
| 118 | + private String table; |
| 119 | + private CacheManager cacheManager; |
| 120 | + private TransformationManager transformationManager; |
| 121 | + |
| 122 | + /** |
| 123 | + * Create a {@link DynamoDbProvider} instance. |
| 124 | + * |
| 125 | + * @return a {@link DynamoDbProvider} |
| 126 | + */ |
| 127 | + public DynamoDbProvider build() { |
| 128 | + if (cacheManager == null) { |
| 129 | + throw new IllegalStateException("No CacheManager provided; please provide one"); |
| 130 | + } |
| 131 | + if (table == null) { |
| 132 | + throw new IllegalStateException("No DynamoDB table name provided; please provide one"); |
| 133 | + } |
| 134 | + DynamoDbProvider provider; |
| 135 | + if (client != null) { |
| 136 | + provider = new DynamoDbProvider(cacheManager, client, table); |
| 137 | + } else { |
| 138 | + provider = new DynamoDbProvider(cacheManager, table); |
| 139 | + } |
| 140 | + if (transformationManager != null) { |
| 141 | + provider.setTransformationManager(transformationManager); |
| 142 | + } |
| 143 | + return provider; |
| 144 | + } |
| 145 | + |
| 146 | + /** |
| 147 | + * Set custom {@link DynamoDbClient} to pass to the {@link DynamoDbClient}. <br/> |
| 148 | + * Use it if you want to customize the region or any other part of the client. |
| 149 | + * |
| 150 | + * @param client Custom client |
| 151 | + * @return the builder to chain calls (eg. <pre>builder.withClient().build()</pre>) |
| 152 | + */ |
| 153 | + public DynamoDbProvider.Builder withClient(DynamoDbClient client) { |
| 154 | + this.client = client; |
| 155 | + return this; |
| 156 | + } |
| 157 | + |
| 158 | + /** |
| 159 | + * <b>Mandatory</b>. Provide a CacheManager to the {@link DynamoDbProvider} |
| 160 | + * |
| 161 | + * @param cacheManager the manager that will handle the cache of parameters |
| 162 | + * @return the builder to chain calls (eg. <pre>builder.withCacheManager().build()</pre>) |
| 163 | + */ |
| 164 | + public DynamoDbProvider.Builder withCacheManager(CacheManager cacheManager) { |
| 165 | + this.cacheManager = cacheManager; |
| 166 | + return this; |
| 167 | + } |
| 168 | + |
| 169 | + /** |
| 170 | + * <b>Mandatory</b>. Provide a DynamoDB table to the {@link DynamoDbProvider} |
| 171 | + * |
| 172 | + * @param table the table that parameters will be retrieved from. |
| 173 | + * @return the builder to chain calls (eg. <pre>builder.withTable().build()</pre>) |
| 174 | + */ |
| 175 | + public DynamoDbProvider.Builder withTable(String table) { |
| 176 | + this.table = table; |
| 177 | + return this; |
| 178 | + } |
| 179 | + |
| 180 | + /** |
| 181 | + * Provide a transformationManager to the {@link DynamoDbProvider} |
| 182 | + * |
| 183 | + * @param transformationManager the manager that will handle transformation of parameters |
| 184 | + * @return the builder to chain calls (eg. <pre>builder.withTransformationManager().build()</pre>) |
| 185 | + */ |
| 186 | + public DynamoDbProvider.Builder withTransformationManager(TransformationManager transformationManager) { |
| 187 | + this.transformationManager = transformationManager; |
| 188 | + return this; |
| 189 | + } |
| 190 | + } |
| 191 | +} |
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